ABCMdb

ABCC7 p.Ala455Glu

Admin's notes:	Class II-III (maturation defect, gating defect) Veit et al.
ClinVar:	c.1364C>A , p.Ala455Glu D , Pathogenic c.1365G>A , p.Ala455= N , Likely benign c.1365G>T , p.Ala455= ? , Uncertain significance
CF databases:	c.1364C>A , p.Ala455Glu D , CF-causing ; CFTR1: The 2 CF chromosomes carrying this mutation are from patients of a French-Canadian origin and they belong to haplotype group Ib. The mutation is detectable by allele-specific oligonucleotide hybridization with PCR-amplified genomic DNA sequence.
Predicted by SNAP2:	C: D (85%), D: D (95%), E: N (66%), F: D (95%), G: D (75%), H: D (95%), I: D (95%), K: D (95%), L: D (95%), M: D (95%), N: D (95%), P: D (95%), Q: D (95%), R: D (95%), S: D (91%), T: D (91%), V: D (85%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	C: N, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: N, T: D, V: D, W: D, Y: D,

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II-III (maturation defect, gating defect) <a href="https://www.ncbi.nlm.nih.gov/pubmed/26823392">Veit et al.</a>
admin on 2016-08-19 15:16:22

Publications
[hide] Insight in eukaryotic ABC transporter function by ... FEBS Lett. 2006 Feb 13;580(4):1064-84. Epub 2006 Jan 19. Frelet A, Klein M
Insight in eukaryotic ABC transporter function by mutation analysis.
FEBS Lett. 2006 Feb 13;580(4):1064-84. Epub 2006 Jan 19., 2006-02-13 [PMID:16442101]

Abstract [show]
With regard to structure-function relations of ATP-binding cassette (ABC) transporters several intriguing questions are in the spotlight of active research: Why do functional ABC transporters possess two ATP binding and hydrolysis domains together with two ABC signatures and to what extent are the individual nucleotide-binding domains independent or interacting? Where is the substrate-binding site and how is ATP hydrolysis functionally coupled to the transport process itself? Although much progress has been made in the elucidation of the three-dimensional structures of ABC transporters in the last years by several crystallographic studies including novel models for the nucleotide hydrolysis and translocation catalysis, site-directed mutagenesis as well as the identification of natural mutations is still a major tool to evaluate effects of individual amino acids on the overall function of ABC transporters. Apart from alterations in characteristic sequence such as Walker A, Walker B and the ABC signature other parts of ABC proteins were subject to detailed mutagenesis studies including the substrate-binding site or the regulatory domain of CFTR. In this review, we will give a detailed overview of the mutation analysis reported for selected ABC transporters of the ABCB and ABCC subfamilies, namely HsCFTR/ABCC7, HsSUR/ABCC8,9, HsMRP1/ABCC1, HsMRP2/ABCC2, ScYCF1 and P-glycoprotein (Pgp)/MDR1/ABCB1 and their effects on the function of each protein.

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307 [138] A455E, P574H cAMP-stimulated apical membrane Cl-currents but current magnitudes were reduced compared to wild-type Electrophysiology of epithelial cells [139] C491S, C1344S, C1355S C491S channels opened almost exclusively to a 3-pS subconductance. Login to comment

[hide] Novel pharmacologic therapies for cystic fibrosis. J Clin Invest. 1999 Feb;103(4):447-52. Zeitlin PL
Novel pharmacologic therapies for cystic fibrosis.
J Clin Invest. 1999 Feb;103(4):447-52., [PMID:10021451]

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33 Examples of Class V mutations include 3849 + 10kb C→T, A455E, and 5T. Login to comment
133 Class IV mutations such as R117H, R334W, R347P, A455E, and P574H are associated with a pancreatic sufficient phenotype or late onset pancreatic insufficiency. Login to comment

[hide] The complex relationships between cystic fibrosis ... Hum Reprod. 1999 Feb;14(2):371-4. Dohle GR, Veeze HJ, Overbeek SE, van den Ouweland AM, Halley DJ, Weber RF, Niermeijer MF
The complex relationships between cystic fibrosis and congenital bilateral absence of the vas deferens: clinical, electrophysiological and genetic data.
Hum Reprod. 1999 Feb;14(2):371-4., [PMID:10099982]

Abstract [show]
Congenital bilateral absence of the vas deferens (CBAVD) is found in 1-2% of infertile males and in most male cystic fibrosis (CF) patients. CF and some of the CBAVD cases were found to share the same genetic background. In this study, 21 males with CBAVD had extensive physical and laboratory testing for symptoms of CF. Possible defective cellular chloride transport was measured by interstitial current measurement of rectal suction biopsies. Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation analysis was performed for 10 common CFTR mutations. CF-related symptoms were found in six men. On laboratory testing slightly abnormal liver and pancreatic function was found in seven patients. The sweat test was found to be abnormal in four patients; interstitial current measurement showed defective chloride excretion in 11 patients. CFTR gene mutations were found in 66% of the patients: eight were compound heterozygotes; in six, only one common mutation could be detected. The 5T allele in one copy of intron 8 was found in four men. CBAVD appears to be a heterogeneous clinical and genetic condition. A CFTR gene mutation was found in both copies of the allele or interstitial current measurement showed defective chloride excretion in 14/21 cases. Genetic counselling is clearly indicated for couples seeking pregnancy through epididymal or testicular sperm aspiration and intracytoplasmic sperm injection.

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58 CFTR mutation analysis was performed for 10 mutations: we analysed for the mutations R117H, A455E, ∆F508, 1717-1G→A, G542X, R553X, R1162X, S1251N, W1282X, and N1303K. Login to comment
81 Chymotr.Ͻ 23/22 CF response (I) ∆F508/R117H 9/7 CF in family 3 33 CARA/oily stools GgtϾ,Chymotr.Ͻ 23/36 CF response (I) ∆F508/- 9/7 4 31 Pelvic re kidney NA 10/22 CF response (I) -/- 7/7 5 32 Sinusitis/nasal Chymotr.Ͻ 50/52 CF low residual (II) A455E/- 9/5 Partner ∆dF508 polyps 6 38 NA NA 40/43 CF high residual (III) A445E/R117H 9/7 7 27 NA GgtϾ,Chymotr.Ͻ 28/44 CF high residual (III) R117H/R553X 7/7 Partner R117H 8 38 Nasal polyps NA 34/51 CF high residual (III) ∆F508/R117H 9/7 Pertussis 9 36 NA NA 58/70 CF high residual (III) ∆F508/- 9/5 10 31 NA GgtϾ 54/70 CF high residual (III) ∆F508/- 9/5 Partner R117H 11 32 Maldescended GgtϾ 16/34 CF high residual (III) -/- 9/7 Single kidney in family testis 12 35 NA NA 14/21 Inconclusive ∆F508/- 9/7 13 29 NA NA 43/70 Normal response (IV) A455E/R117H 9/7 14 38 NA NA 32/55 Normal response (IV) R117H/1717-1→G→A 7/7 15 29 NA GgtϾ 44/66 Normal response (IV) ∆F508/R117H 9/7 16 28 NA NA 42/48 Normal response (IV) R117H/- 7/7 17 36 NA NA 22/44 Normal response (IV) -/- 7/5 Non-Caucasian 18 34 NA NA 57/30 Normal response (IV) -/- 7/7 Non-Caucasian 19 39 NA NA 36/52 Normal response (IV) -/- 7/7 Non-Caucasian 20 31 NA NA 16/30 Normal response (IV) -/- 7/7 Non-Caucasian 21 34 NA NA 20/41 Normal response (IV) -/- 7/7 NA ϭ no abnormalities, GgT ϭ gamma glutamyl transpeptidase, Chymotr. Login to comment

[hide] Clinical presentation of exclusive cystic fibrosis... Thorax. 1999 Mar;54(3):278-81. Bronsveld I, Bijman J, Mekus F, Ballmann M, Veeze HJ, Tummler B
Clinical presentation of exclusive cystic fibrosis lung disease.
Thorax. 1999 Mar;54(3):278-81., [PMID:10325907]

Abstract [show]
The diagnosis of cystic fibrosis (CF) is based on the occurrence of two mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and on assays that measure the basic defect of abnormal chloride transport in the affected organs. However, in cases of atypical CF not all diagnostic tests may be positive. We present a patient with an atypical CF phenotype in whom the only presenting symptom was severe CF-like lung disease substantiated by an abnormal nasal potential difference. Genetic analysis showed that the patient was a symptomatic heterozygote, which suggests that one lesion in the CFTR gene may be sufficient to cause CF-like lung disease.

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68 Other cases of CF with normal sweat test results and pulmonary disease, as described for patients carrying the A455E or 3849+10 kb C->T mutation,7 8 22 23 can clearly be diagnosed by an abnormal ICM even when there are few or no clinical signs of gastrointestinal involvement.10 The CFTR gene was screened for disease causing lesions in all exons and flanking intron sequences and on one chromosome a sequence alteration in a donor splice site was found Figure 2 Nasal potential diVerence (PD) measurements of the patient (x) and mean (SD) PD values of 25 controls (L) and 23 patients with CF ( ) following superfusion with saline solution, amiloride (10-4 M) in saline solution, Cl-free solution with amiloride, isoprenaline (10-4 M) in Cl-free solution with amiloride, and ATP (10-3 M) in Cl-free solution with amiloride and isoprenaline. Login to comment

[hide] Processing of CFTR bearing the P574H mutation diff... J Cell Sci. 1999 Jul;112 ( Pt 13):2091-8. Ostedgaard LS, Zeiher B, Welsh MJ
Processing of CFTR bearing the P574H mutation differs from wild-type and deltaF508-CFTR.
J Cell Sci. 1999 Jul;112 ( Pt 13):2091-8., [PMID:10362539]

Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR) containing the deltaF508 mutation is retained in the endoplasmic reticulum (ER). This defect can be partially overcome by a reduction in temperature which allows some of the deltaF508 protein to exit the ER and move to the cell surface. Earlier studies showed that the CF-associated mutants, P574H and A455E, were also misprocessed. In this study, we found that processing of P574H and A455E was also temperature-sensitive; at 26 degrees C, some of the protein matured. In contrast to other CFTR mutants, P574H accumulated in punctate cytoplasmic bodies that colocalized with endoplasmic reticulum (ER) markers. At 26 degrees C, these bodies were no longer present. P574H showed a prolonged association with Hsp70 and also colocalized with Hsp70. We used brefeldin A (BFA) to determine which processing step(s) was altered by reduced temperature. Unlike wild-type CFTR, which was converted into an intermediate that was stable in the presence of BFA at 37 degrees C, deltaF508 and P574H produced the intermediate only when the temperature was reduced to 26 degrees C. Furthermore the wild-type intermediate was not associated with Hsp70. These data suggest that formation of the stable intermediate is a key temperature-sensitive step and appears to be coincident with release of the wild-type protein from Hsp70.

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18 Earlier studies showed that the CF-associated mutants, P574H and A455E, were also misprocessed. Login to comment
19 In this study, we found that processing of P574H and A455E was also temperature-sensitive; at 26°C, some of the protein matured. Login to comment
27 We earlier studied two other CF-associated mutations located in NBD1, A455E and P574H (Sheppard et al., 1995). Login to comment
29 However, A455E and P574H generate reduced net epithelial current because the proteins are misprocessed and few functional channels reach the plasma membrane (Sheppard et al., 1995; Champigny et al., 1995). Login to comment
30 Nevertheless, the processing defect of A455E and P574H is less pronounced than that of ∆F508 and the resulting clinical phenotype is less severe (Kristidis et al., 1992; Kerem et al., 1990a; Veeze et al., 1994; Gan et al., 1995). Login to comment
32 In this study, we compared the processing of P574H and A455E mutants to that of ∆F508. Login to comment
37 Using the pcDNA3-6His-CFTR as a backbone, we made the constructs A455E, P574H and ∆F508 (Kunkel, 1985) and confirmed the mutations by DNA sequencing in both directions. Login to comment
65 RESULTS Because earlier studies suggested that lowering the temperature allowed ∆F508 to fold correctly and exit the ER (Denning et al., 1992a; Lukacs et al., 1993; Sato et al., 1996), we first examined the temperature-sensitivity of A455E and P574H processing. Login to comment
70 For the NBD1 mutants, ∆F508 (B), A455E (C) and P574H (D), band B was the primary form detected at 37°C. Login to comment
74 For ∆F508 (B) and A455E (C), the relative amount of band C was minimal at each time at 37°C. Although the relative amount of band C in P574H (D) was also low, it increased slowly with time at 37°C. Login to comment
75 When the temperature was reduced to 26°C, the relative amount of band C for ∆F508 and A455E increased modestly, while the amount of P574H band C relative to total P574H increased. Login to comment
77 These results indicate that, like ∆F508, both A455E and P574H are temperature-sensitive processing mutants. Login to comment
78 Moreover, P574H makes relatively more band C at both 37°C and 26°C than either ∆F508 or A455E. Login to comment
82 P574H and A455E are temperature-sensitive mutants. Login to comment
83 COS-7 cells were electroporated with pcDNA3 vectors encoding wild-type CFTR (A), ∆F508 (B), A455E (C), and P574H (D). Login to comment
111 We used immunocytochemistry to determine if the cellular distribution of ∆F508, A455E and P574H was consistent with the quantitative biochemical differences we had observed. Login to comment
114 The fluorescence pattern of ∆F508 (C) and A455E (E) at 37°C resembles the reticular pattern characteristic of ER with an absence of plasma membrane staining. Login to comment
115 When the cells were incubated at 26°C, cytoplasmic staining became more diffuse and the outline of the cell membrane was occasionally detectable in ∆F508 (D) and A455E (F). Login to comment
118 Immunofluorescence in COS-7 cells electroporated with wild-type-CFTR (A,B); ∆F508 (C,D); A455E (E,F); and P574H (G,H). Login to comment
165 DISCUSSION Earlier work showed that CFTR containing the CF-associated mutations ∆F508, A455E, or P574H decreases cell membrane Cl- current primarily because the mutant proteins fail to fold correctly and therefore do not traffic out of the ER (Cheng et al., 1990; Lukacs et al., 1994; Ward and Kopito, 1994; Sheppard et al., 1995; Qu and Thomas, 1996; Qu et al., 1997; Yang et al., 1993; Zhang et al., 1998). Login to comment
185 We found that, like ∆F508, the processing of P574H and A455E is temperature-sensitive. Login to comment
186 Moreover, unlike ∆F508 and A455E, P574H formed some mature protein at 37°C, and at 26°C, P574H generated relatively more mature protein than ∆F508. Login to comment
189 This is consistent with the clinical phenotype in CF patients: P574H and A455E are associated with a milder, pancreatic-sufficient phenotype and ∆F508 is associated with a severe, pancreatic-insufficient clinical phenotype (Kerem et al., 1990a,b; Kristidis et al., 1992; Veeze et al., 1994; Gan et al., 1995). Login to comment
197 These inclusions were not present in wild-type, ∆F508, A455E or any other mutant we have studied. Login to comment

[hide] Proportion of cystic fibrosis gene mutations not d... JAMA. 1999 Jun 16;281(23):2217-24. Mak V, Zielenski J, Tsui LC, Durie P, Zini A, Martin S, Longley TB, Jarvi KA
Proportion of cystic fibrosis gene mutations not detected by routine testing in men with obstructive azoospermia.
JAMA. 1999 Jun 16;281(23):2217-24., 1999-06-16 [PMID:10376575]

Abstract [show]
CONTEXT: Infertile men with obstructive azoospermia may have mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, many of which are rare in classic cystic fibrosis and not evaluated in most routine mutation screening. OBJECTIVE: To assess how often CFTR mutations or sequence alterations undetected by routine screening are detected with more extensive screening in obstructive azoospermia. DESIGN: Routine screening for the 31 most common CFTR mutations associated with the CF phenotype in white populations, testing for the 5-thymidine variant of the polythymidine tract of intron 8 (IVS8-5T) by allele-specific oligonucleotide hybridization, and screening of all exons through multiplex heteroduplex shift analysis followed by direct DNA sequencing. SETTING: Male infertility clinic of a Canadian university-affiliated hospital. SUBJECTS: Of 198 men with obstructive (n = 149) or nonobstructive (n = 49; control group) azoospermia, 64 had congenital bilateral absence of the vas deferens (CBAVD), 10 had congenital unilateral absence of the vas deferens (CUAVD), and 75 had epididymal obstruction (56/75 were idiopathic). MAIN OUTCOME MEASURE: Frequency of mutations found by routine and nonroutine tests in men with obstructive vs nonobstructive azoospermia. RESULTS: Frequency of mutations and the IVS8-5T variant in the nonobstructive azoospermia group (controls) (2% and 5.1% allele frequency, respectively) did not differ significantly from that in the general population (2% and 5.2%, respectively). In the CBAVD group, 72 mutations were found by DNA sequencing and IVS8-5T testing (47 and 25, respectively; P<.001 and P = .002 vs controls) vs 39 by the routine panel (P<.001 vs controls). In the idiopathic epididymal obstruction group, 24 mutations were found by DNA sequencing and IVS8-5T testing (12 each; P=.01 and P=.14 vs controls) vs 5 by the routine panel (P=.33 vs controls). In the CUAVD group, 2 mutations were found by routine testing (P=.07 vs controls) vs 4 (2 each, respectively; P=.07 and P=.40 vs controls) by DNA sequencing and IVS8-5T testing. The routine panel did not identify 33 (46%) of 72, 2 (50%) of 4, and 19 (79%) of 24 detectable CFTR mutations and IVS8-5T in the CBAVD, CUAVD, and idiopathic epididymal obstruction groups, respectively. CONCLUSIONS: Routine testing for CFTR mutations may miss mild or rare gene alterations. The barrier to conception for men with obstructive infertility has been overcome by assisted reproductive technologies, thus raising the concern of iatrogenically transmitting pathogenic CFTR mutations to the progeny.

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28 Analysis for 31 of the most common CFTR mutations found within the white CF population,60 consisting of ⌬F508, W1282X, G542X, G551D, N1303K, R553X, G85E, R117H, S549N, V520F, R334W, A455E, R347P, R1162X, Y122X, S549R, 621+1G→T, ⌬I507, R560T, R347H, 3659delC, Q493X, 1898+1G→T, 711+1G→T, 3849+10C→T, 1717-1G→A, 3849+4A→G, 3905insT, 1078delT, 2183AA→G, and 2789+5G→A. Briefly, the technique involved amplification by polymerase chain reaction61 of the relevant exons, followed by digestion with appropriate restriction endonucleases and acrylamide gel electrophoresis with ethidium bromide staining. Login to comment

[hide] Two buffer PAGE system-based SSCP/HD analysis: a g... Eur J Hum Genet. 1999 Jul;7(5):590-8. Liechti-Gallati S, Schneider V, Neeser D, Kraemer R
Two buffer PAGE system-based SSCP/HD analysis: a general protocol for rapid and sensitive mutation screening in cystic fibrosis and any other human genetic disease.
Eur J Hum Genet. 1999 Jul;7(5):590-8., [PMID:10439967]

Abstract [show]
The large size of many disease genes and the multiplicity of mutations complicate the design of an adequate assay for the identification of disease-causing variants. One of the most successful methods for mutation detection is the single strand conformation polymorphism (SSCP) technique. By varying temperature, gel composition, ionic strength and additives, we optimised the sensitivity of SSCP for all 27 exons of the CFTR gene. Using simultaneously SSCP and heteroduplex (HD) analysis, a total of 80 known CF mutations (28 missense, 22 frameshift, 17 nonsense, 13 splicesite) and 20 polymorphisms was analysed resulting in a detection rate of 97.5% including the 24 most common mutations worldwide. The ability of this technique to detect mutations independent of their nature, frequency, and population specificity was confirmed by the identification of five novel mutations (420del9, 1199delG, R560S, A613T, T1299I) in Swiss CF patients, as well as by the detection of 41 different mutations in 198 patients experimentally analysed. We present a three-stage screening strategy allowing analysis of seven exons within 5 hours and analysis of the entire coding region within 1 week, including sequence analysis of the variants. Additionally, our protocol represents a general model for point mutation analysis in other genetic disorders and has already been successfully established for OTC deficiency, collagene deficiency, X-linked myotubular myopathy (XLMTM), Duchenne and Becker muscular dystrophy (DMD, BMD), Wilson disease (WD), Neurofibromatosis I and II, Charcot-Marie-Tooth disease, hereditary neuropathy with liability to pressure palsies, and defects in mitochondrial DNA. No other protocol published so far presents standard SSCP/HD conditions for mutation screening in different disease genes.

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20 The distribution of analysed known mutations is similar to that of the total number of mutations in the entire CFTR gene: missense mutations account for 35% (G27E, G85E, R117H, A120T, I148T, H199Y, R334W, T338I, R347P, R347H, A455E, M718K, S5449N, S5449I, G551D, R560T, R560S, S945L, S977P, I1005R, R1066C, R1070Q, M1101K, D1152H, S1235R, R1283M, N1303K, N1303H), followed by 28% of frameshift mutations (175delC, 394delTT, 457TAT- > G, 905delG, 1078delT, I507, F508, 1609delCA, 1677delTA, 2143delT, 2176insC, 218delA, 2184insA, 2869insG, 3659delC, 3732delA, 3821delT, 3905insT, 4016insT, 4172delGC, 4382delA), 21% of nonsense mutations (Q30X, Q39X, Q220X, W401X, Q525X, G542X, Q552X, R553X, V569X, E585X, K710X, R792X, Y1092X, R1162X, S1255X, W1282X, E1371X), and 16% of splice site mutations (621 + 1G- > T, 711 + 1G- > T, 711 + 5G- > A, 1717-1G- > A, 1898 + 1G- > A, 1898 + 5G- > T, 2789 + 5G- > A, 3271 + 1G- > A, 3272-26A- > G, 3601-17T- > C, 3849 + 4A- > G, 3849 + 10kbC- > T, 4374 + 1G- > T). Login to comment
34 Intron 19, all 27 exons and their exon-intron boundaries, including the 24 most common mutations worldwide (G85E, R117H, 621 + 1G- > T, 711 + 1G- > T, 1078delT, R334W, R347P, A455E, I507, F508, 1717-1G- > A, G542X, S549N, G551D, R553X, R560T, 1898 + 1G- > A, 2184delA, 2789 + 5G- > A, R1162X, 3659delC, 3849 + 10kbC- > T, W1282X, N1303K) (Cystic Fibrosis Genetic Analysis Consortium 1994), and the 15 most common mutations in our population (I148T, 1078delT, R334W, R347P, F508, 1717-1G- > A, G542X, R553X, 2347delG, D1152H, R1162X, 3849 + 10kbC- > T, 3905insT, W1282X, N1303K), were considered in this study. Login to comment

[hide] Analysis of 31 CFTR mutations by polymerase chain ... J Med Screen. 1999;6(2):67-9. Gasparini P, Arbustini E, Restagno G, Zelante L, Stanziale P, Gatta L, Sbaiz L, Sedita AM, Banchieri N, Sapone L, Fiorucci GC, Brinson E, Shulse E, Rappaport E, Fortina P
Analysis of 31 CFTR mutations by polymerase chain reaction/oligonucleotide ligation assay in a pilot screening of 4476 newborns for cystic fibrosis.
J Med Screen. 1999;6(2):67-9., [PMID:10444722]

Abstract [show]
OBJECTIVES: Molecular biological testing for genetic diseases has grown rapidly, but speed, accuracy, specificity, sensitivity, throughput, and cost become more important as large scale screening is considered. This is a pilot study of an assay for the simultaneous detection of up to 31 cystic fibrosis mutations in a multicentre population based screening of 4476 Italian newborns. METHODS: The assay is a polymerase chain reaction, followed by an oligonucleotide ligation assay (PCR/OLA) and finally a sequence coded separation. It allows the detection of up to 31 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Guthrie spots were used as a source of template DNA. RESULTS: 144 carriers were detected during the analysis of 4476 samples, which translates into a carrier frequency of 1/31.1. Forty two carriers were detected from 1341 samples in Pavia (1/31.9), 53 from 1574 in Turin (1/29.7), and 49 from 1561 in San Giovanni Rotondo (1/31.8). Fifteen different mutations were detected, the most common being delta F508 (0.625). Other common mutations included G542X (16 of 144), which was particularly common in southern Italy (14 of 49), N1303K (8 of 144), and R117H (8 of 144), detected only in the northern centres. CONCLUSIONS: PCR/OLA is a robust, accurate, user friendly method for cystic fibrosis screening of newborns using blood spots in a semiautomated way at a low cost per mutation (0.8 Euro).

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46 Table 1 Mutations analysed in the CFTR gene using polymerase chain reaction/oligonucleotide litigation assay/sequence coded separation Mutation Location Nucleotide Result F508 Exon 10 3 bp deletion Deletion of Phe-508 I507 Exon 10 3 bp deletion Deletion of Ile-507 (or -506) Q493X Exon 10 C-1609 →→ T Gln-493 → Stop V520F Exon 10 G-1690 → T Val-520 → Phe 1717-1G → A Intron 10 G-1717-1 → A 3`-splice site mutation G542X Exon 11 G-1756 → T Gly-542 → Stop G551D Exon 11 G-1784 → A Gly-551 → Asp R553X Exon 11 C-1789 → T Arg-553 → Stop R560T Exon 11 G-1811 → C Arg-560 → Thr S549R Exon 11 T-1779 → G Ser-549 → Arg S549N Exon 11 G-1778 → A Ser-549 → Asn 3849+10 kb C → T Intron 19 C-3849+10 kb → T Splice mutation 3849+4A → G Intron 19 A-3849+4 → G Splice mutation R1162X Exon 19 C-3616 → T Arg-1162 → Stop 3659delC Exon 19 1 bp deletion Frameshift W1282X Exon 20 G-3978 → A Trp-1282 → Stop 3905insT Exon 20 1 bp insertion Frameshift N1303K Exon 21 C-4041 → G Asn-1303 → Lys G85E Exon 3 G-386 → A Gly-85 → Glu 621+1G → T Intron 4 G-621+1 → T 5`-splice site mutation R117H Exon 4 G-482 → A Arg-117 → His Y122X Exon 4 T-498 → A Tyr-122 → Stop 711+1G → T Intron 5 G-711+1 → T 5`-splice site mutation 1078delT Exon 7 1 bp deletion Frameshift R347P Exon 7 G-1172 → C Arg-347 → Pro R347H Exon 7 G-1172 → A Arg-347 → His R334W Exon 7 C-1132 → T Arg-334 → Trp A455E Exon 9 C-1496 → A Ala-455 → Glu 1898+1G → A Intron 12 G-1898+1 → A 5`-splice site mutation 2184delA Exon 13 Deletion A-2184; A-2183 → G Frameshift 2789+5G → A Intron 14B G-2789+5 → A Splice mutation Table 2 Summary of cystic fibrosis screening results No of samples analysed Normal subjects Carriers Carrier frequency Turin 1574 1521 53 1/29.7 Pavia 1341 1299 42 1/31.9 San Giovanni Rotondo 1561 1512 49 1/31.8 Total 4476 4332 144 1/31.1 Table 3 Detailed list of mutations detected in the Italian population Centre F508 G542X R347P 2183-AG N1303K 711+1GT 1717-1A R347H R117H 1898+1G 2789+5G W1282X R1162X I507 Other TO 33 2 1 1 5 1 1 2 3 2 2 - - - PV 27 - - 1 2 - 1 - 5 - 1 2 1 1 SGR 30 14 2 1 1 1 - - - - - - - - TO, Dipartimento di Patologia Clinica, Ospedale Infantile "Regina Margherita, Torino; PV, Istituto di Anatomia Patologica, Sezione di Anatomia Patologica, Università di Pavia, Pavia; SGR, Servizio di Genetica Medica and Divisione di Neonatologia, IRCCS Casa Sollievo della SoVerenza, San Giovanni Rotondo, Foggia. Login to comment

[hide] [Respiratory disease in cystic fibrosis: from phys... Rev Mal Respir. 1999 Sep;16(4):495-509. Reynaud-Gaubert M
[Respiratory disease in cystic fibrosis: from physiopathology to therapy. Kinesitherapy and pulmonary transplantation excluded].
Rev Mal Respir. 1999 Sep;16(4):495-509., [PMID:10549060]

Abstract [show]
Respiratory disease is the major cause of morbidity and mortality in cystic fibrosis. Cystic fibrosis was long treated in the pediatric setting, but improved survival has led to the implication of adult pneumology in therapeutic management. Since the gene causing cystic fibrosis has been clone, our knowledge of the pathophysiology of the disease has literally exploded, particularly concerning the deleterious consequences of defective expression and distribution of CFTR (cystic fibrosis transmembrane conductance regulator) protein in chronic lung inflammation and infection. This knowledge has led to an optimization of existing therapeutic strategies and to the formulation of hypotheses for the development of new pharmaceutical reagents, allowing an assessment of disease outcome not only in terms of survival but also in terms of quality of life. Early in vivo clinical trials have been encouraging although the efficacy of gene transfer and expression remain modest and the optimal vector remains to be determined. Different potential pharmacological approaches are being studied in order to correct for defective CFTR function at different levels of gene mutation, and to modulate the disorder in transepithelial ionic transfer. One could expect in the near future to see combinations of complementary genotype-specific drugs used for the treatment of cystic fibrosis after patient genotyping to categorize the type of mutation.

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70 - Une 5e classe, plus récemment individualisée, cor- respondrait à une insuffisance quantitative de l`expression membranaire de la protéine par ailleurs normale (ex A455E). Login to comment

[hide] Cystic fibrosis mutations lead to carboxyl-termina... J Biol Chem. 2000 Jun 30;275(26):19577-84. Van Oene M, Lukacs GL, Rommens JM
Cystic fibrosis mutations lead to carboxyl-terminal fragments that highlight an early biogenesis step of the cystic fibrosis transmembrane conductance regulator.
J Biol Chem. 2000 Jun 30;275(26):19577-84., 2000-06-30 [PMID:10764788]

Abstract [show]
Inefficient delivery of the cystic fibrosis transmembrane conductance regulator (CFTR) to the surface of cells contributes to disease in the majority of cystic fibrosis patients. Analysis of cystic fibrosis-associated missense mutations in the first nucleotide binding domain (NBD1), including A455E, S549R, Y563N, and P574H, revealed reduced levels of mature CFTR with elevated levels of carboxyl-terminal polypeptide fragments of 105 and 90 kDa. These fragments appear early in biogenesis and degrade rapidly in four distinct cell types tested including the bronchial epithelial IB3-1 cell line. They were detected at highest levels with CFTRA455E where the 105-kDa fragment accounted for 40% of newly synthesized polypeptide but for only 20 and 7% of nascent wild type and mutant DeltaF508 proteins, respectively. The bands represent core- and unglycosylated forms of the same CFTR fragment supporting that precursor forms are correctly inserted into the membrane of the endoplasmic reticulum. Proteolytic cleavage would be predicted to occur on the cytosolic face of the endoplasmic reticulum within the NBD1-R domain segment, but pharmacological testing did not support involvement of the 26 S proteasome. The examined missense mutations in NBD1 manifest differently than the major mutant, DeltaF508, and highlight a critical conformational aspect of biogenesis of CFTR.

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1 Analysis of cystic fibrosis-associated missense mutations in the first nucleotide binding domain (NBD1), including A455E, S549R, Y563N, and P574H, revealed reduced levels of mature CFTR with elevated levels of carboxyl-terminal polypeptide fragments of 105 and 90 kDa. Login to comment
41 EXPERIMENTAL PROCEDURES Construction of CFTR Expression Plasmids-The CFTR mutants A455E, S549R, P574H, and Y563N were generated from pBQ6.2 (34) as described previously (35). Login to comment
84 Analysis of the S549R mutant showed measurable but intermediate levels of band C, whereas A455E, Y563N, and P574H mutants showed markedly reduced levels using both tagged and untagged CFTR. Login to comment
88 Predominant levels of CHA-CFTRwt appear at the cell surface, in contrast to CHA-⌬F508 and CHA-A455E, as described in alternate reports with untagged versions (18, 44). Login to comment
92 Identification of Carboxyl CFTR Derivatives-In addition to full-length CFTR forms, both the M3A7 and the anti-HA antibodies revealed products with relative molecular masses of 105 and 90 kDa that were most prominent in detergent extracts of HEK293 cells expressing the A455E and S549R mutants (Fig. 1, B and C, lanes 4 and 5). Login to comment
97 The first involved an analysis of the extract preparation to examine the compartmentalization of CFTR, the second involved analysis of the intermediates at reduced expression levels with the A455E mutant, and the third involved expression in alternate cell types. Login to comment
100 Immunoblot analysis indicated that less than 10% of total immunoreactive band B or carboxyl-terminal polypeptides were present in the original CHA-A455E pellet (Fig. 3A). Login to comment
102 The occurrence of the 90-kDa band, most prominent with the A455E mutant, does suggest that it is relatively less soluble. Login to comment
105 Representative COS-7 cells transfected with (A) CHA-CFTRwt, (B) CHA-⌬F508, (C) CHA-A455E, and (D) CHA-S549R are shown. Login to comment
106 Indirect immunofluorescence revealed a uniform cell surface staining with the monoclonal anti-HA antibody for the wt protein in contrast to the perinuclear staining of the ⌬F508 and A455E mutants. Login to comment
119 1/20 the amount of the CHA-A455E expression plasmid (Fig. 3C). Login to comment
122 Transient transfections were carried out with CHA-tagged CFTRwt, ⌬F508, and A455E in COS-7, CHO-duk- , and CF bronchial epithelium IB3-1 cell lines. Login to comment
123 Immunoblot analysis of detergent extracts indicated that although the levels varied between the cell types, CHA-A455E consistently revealed the most prominent accumulation of the 105-and 90-kDa bands (Fig. 4, A-C). Login to comment
127 The increased sensitivity clearly shows the accumulation of the 105-kDa intermediate in both the wt and A455E extracts. Login to comment
136 In contrast, no mature forms were detected for the A455E mutation (right panel) or with prolonged pulse and/or chase periods (data not shown). Login to comment
137 The 105-and 90-kDa carboxyl-terminal fragments were evident for both CFTRwt and A455E as early as the completion of the pulse (15 min) and rapidly disappeared during the chase. Login to comment
138 These untagged proteins were detectable with a CFTR antibody mixture (M3A7 and L12B4) and were consistently most prominent for the A455E mutant. Login to comment
146 HEK293 cells were transfected with pCMV (vector alone), CHA-A455E, or with mixtures of pCMV and CHA-A455E to maintain constant plasmid-lipid ratios for transfection. Login to comment
155 The half-life of the 105-kDa intermediate of both CFTRwt and A455E was determined to be very similar to that of band B (t1/2 ϳ30-40 min) (16, 17) emphasizing that this fragment is susceptible to proteolysis. Login to comment
161 Epitope-tagged versions of wt and the A455E mutant gave consistent results, as did radioactively labeled and immunoprecipitated untagged CFTR polypeptides (data not shown). Login to comment
172 RIPA soluble CFTR peptides were immunoprecipitated demonstrating that the inhibitors had no effect on the prevalence of the 105-and 90-kDa polypeptides formed during A455E biosynthesis (Fig. 7B). Login to comment
181 It is imposed on the wt protein but is more prominent in the presence of missense mutations such as A455E or S549R. Login to comment
188 The relative levels of the 105-kDa band with CFTRwt, A455E, and ⌬F508 were determined by phosphorimage analysis. Login to comment
196 Further, it is evident that for enhanced proteolytic activity, the mutated amino acid need not be present in the resulting carboxyl fragments as size estimation would preclude this for at least the A455E mutant. Login to comment
209 It would therefore be interesting to closely examine its interaction with the S549R and A455E CFTR mutants. Login to comment
228 The proximity of the amino acid deletion to a proteolytic site may account for this; however, analysis of cells expressing CFTR versions with both the ⌬F508 mutation and either S549R or A455E mutations retain the formation of prominent levels of the carboxyl-terminal fragments (data not shown). Login to comment
237 This is consistent with the findings of the wt protein but less discernible for some mutations such as A455E. Login to comment
238 The A455E, Y563N, and P574H mutations do appear to be able to achieve at least nominal levels of chloride conduction at the cell surface based both on the presenting phenotype in CF patients (54) and on single channel and whole cell current measurements (55) in heterologous expression systems. Login to comment
239 In contrast to the Y563N and P574H mutations, where low levels of mature band C forms were detectable with long exposure and/or long label incorporation times in HEK293 cells (data not shown), fully glycosylated protein could not be detected for A455E using our assay systems. Login to comment
240 Of the NBD1 missense mutations surveyed, A455E degradation products appeared at the highest levels relative to full-length nascent CFTR such that immature band B may be too low to lead to detectable levels of band C. Login to comment

[hide] Genotype and phenotype in cystic fibrosis. Respiration. 2000;67(2):117-33. Zielenski J
Genotype and phenotype in cystic fibrosis.
Respiration. 2000;67(2):117-33., [PMID:10773783]

Abstract [show]
Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene which encodes a protein expressed in the apical membrane of exocrine epithelial cells. CFTR functions principally as a cAMP-induced chloride channel and appears capable of regulating other ion channels. Besides the most common mutation, DeltaF508, accounting for about 70% of CF chromosomes worldwide, more than 850 mutant alleles have been reported to the CF Genetic Analysis Consortium. These mutations affect CFTR through a variety of molecular mechanisms which can produce little or no functional CFTR at the apical membrane. This genotypic variation provides a rationale for phenotypic effects of the specific mutations. The extent to which various CFTR alleles contribute to clinical variation in CF is evaluated by genotype-phenotype studies. These demonstrated that the degree of correlation between CFTR genotype and CF phenotype varies between its clinical components and is highest for the pancreatic status and lowest for pulmonary disease. The poor correlation between CFTR genotype and severity of lung disease strongly suggests an influence of environmental and secondary genetic factors (CF modifiers). Several candidate genes related to innate and adaptive immune response have been implicated as pulmonary CF modifiers. In addition, the presence of a genetic CF modifier for meconium ileus has been demonstrated on human chromosome 19q13.2. The phenotypic spectrum associated with mutations in the CFTR gene extends beyond the classically defined CF. Besides patients with atypical CF, there are large numbers of so-called monosymptomatic diseases such as various forms of obstructive azoospermia, idiopathic pancreatitis or disseminated bronchiectasis associated with CFTR mutations uncharacteristic for CF. The composition, frequency and type of CFTR mutations/variants parallel the spectrum of CFTR-associated phenotypes, from classic CF to mild monosymptomatic presentations. Expansion of the spectrum of disease associated with the CFTR mutant genes creates a need for revision of the diagnostic criteria for CF and a dilemma for setting nosologic boundaries between CF and other diseases with CFTR etiology.

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94 Various mutations may be associated with reduced biosynthesis of fully active CFTR due to partially aberrant splicing (3849+10kbC→T) [25], promoter mutations or inefficient trafficking (A455E) [26, 27]. Login to comment
147 Thus far, the strongest association between mild pulmonary disease and a specific CFTR mutation was found for the missense allele A455E [57, 60, 62]. Login to comment
165 Both studies showed that certain mild alleles (R117H; A455E; 3849+10kbC→T) from class IV or V tend to be associated with significantly lower Cl sweat levels than those for severe alleles ('F508; 621+1G→T; G542X; R553X, etc.). Login to comment

[hide] A novel mutation in the CFTR gene correlates with ... J Med Genet. 2000 Mar;37(3):215-8. Wang J, Bowman MC, Hsu E, Wertz K, Wong LJ
A novel mutation in the CFTR gene correlates with severe clinical phenotype in seven Hispanic patients.
J Med Genet. 2000 Mar;37(3):215-8., [PMID:10777364]

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552 The proportion of patients homozygous for F508 remains quite constant between the three age groups, whereas there is a decline in that of the patients carrying the 621+1G→T/ F508 genotype and an increase of those having a F508/A455E or 621+1G→T/A455E genotype. Login to comment
554 The A455E mutation group contains all the patients with that mutation, independently of the second mutation composing their genotype. Login to comment
555 The CF patients carrying the 621+1G→T mutation, but not A455E, were included in a unique group. Login to comment
556 Patients homozygous or compound heterozygous for the F508 mutation, without the 621+1G→T or the A455E mutation, were grouped together. Login to comment
557 We observed an increase of A455E and a depletion of 621+1G→T at older age groups, whereas the frequency of the F508 mutation stayed constant (table 1B). Login to comment
559 The Kaplan-Meier survival analysis could not be performed considering the three mutations because there were no dead patients in the A455E group. Login to comment
564 The F508 and 621+1G→T alleles are known to be severe mutations conferring pancreatic insuYciency when they are combined with another severe mutation.4 8 9 The A455E allele is a mild mutation associated with pancreatic suYciency and exerts a dominant eVect on the severe mutations. Login to comment
565 Compound heterozygotes for the A455E mutation have a milder pulmonary disease, no meconium ileus, and no late complications, such as diabetes and liver cirrhosis.2 Therefore, since pulmonary insuYciency is the major cause of mortality in cystic fibrosis, it is not unexpected that no CF patients carrying the A455E mutation have died unlike the 13% of those with two severe mutations. Login to comment
570 SYLVAIN R RIVARD* CHRISTIAN ALLARD† JEAN-PIERRE LEBLANC† MARCEL MILOT† GERVAIS AUBIN† FERNAND SIMARD† CLAUDE FÉREC‡ MARC DE BRAEKELEER†§¶ *Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Canada Table 1 Distribution of cystic fibrosis patients diagnosed before the age of 5 by age groups in Saguenay-Lac-Saint-Jean, (A) by genotype, (B) by mutation 0-10 years 10.1-20 years Over 20 years All ages No % No % No % No % (A) Genotype F508/ F508 15 (1) 40.5 21 (2) 36.2 18 (3) 42.9 54 (6) 39.4 F508/621+1G→T 12 (1) 32.4 16 (1) 27.6 10 (1*) 23.8 38 (3*) 27.7 F508/A455E 1 2.7 6 10.3 5 11.9 12 8.8 F508/I148T 1 2.7 1 1.7 2 1.5 F508/Y1092X 3 (1) 5.2 1 2.4 4 (1) 2.9 F508/Q890X 1 2.4 1 0.7 F508/R1158X 1 2.4 1 0.7 621+1G→T/621+1G→T 2 (1) 5.4 4 6.9 1 2.4 7 (1) 5.1 621+1G→T/A455E 1 2.7 4 6.9 3 7.1 8 5.8 621+1G→T/711+1G→T 2 (1) 5.4 2 (1) 3.4 4 (2) 2.9 621+1G→T/Y1092X 1 2.7 1 0.7 621+1G→T/S489X 1 2.7 1 0.7 621+1G→T/G85E 1 (1) 1.7 1 (1) 2.4 2 (2) 1.5 A455E/R117C 1 2.7 1 0.7 N1303K/I148T 1 2.4 1 0.7 Total 37 58 42 137 Death (4) 10.8 (6) 10.3 (5*) 11.9 (15*) 10.9 (B) Mutation F508 16 (1) 43.2 25 (3) 43.1 21 (3) 51.2 62 (7) 45.6 621+1G→T 18 (3) 48.6 23 (3) 39.7 12 (2*) 29.3 53 (8*) 39.0 A455E 3 8.1 10 17.2 8 19.5 21 15.4 Total 37 58 41 136 Death (4) 10.8 (6) 10.3 (5*) (12.2) (15*) (11.0) ( ): Number of deaths. Login to comment
573 1 0.8 0.6 0.4 0.2 0 50 Age (y) A455E mutation ∆F508 mutation 621 + 1G T mutation Cumulativesurvival 0 40302010 Letters †Clinique de Fibrose Kystique, Complexe Hospitalier de la Sagamie, Chicoutimi, Canada ‡Établissement de Transfusion Sanguine de Bretagne Occidentale (ETSBO), Brest, France §Institut National d`Etudes Démographiques, Paris, France ¶Laboratoire d`Anthropologie et de Démographie Génétiques, Faculté des Sciences de l`Homme, Université Victor Segalen Bordeaux 2, 3ter Place de la Victoire, F-33076 Bordeaux Cedex, France 1 Boat TF, Welsh MJ, Beaudet AL. Cystic fibrosis. Login to comment
576 New York: McGraw-Hill, 1989:2649-80. 2 De Braekeleer M, Allard C, Leblanc JP, Simard F, Aubin G. Genotype-phenotype correlation in cystic fibrosis patients compound heterozygous for the A455E mutation. Login to comment

[hide] Correlation between mutations and age in cystic fi... J Med Genet. 2000 Mar;37(3):225-7. Rivard SR, Allard C, Leblanc JP, Milot M, Aubin G, Simard F, Ferec C, de Braekeleer M
Correlation between mutations and age in cystic fibrosis in a French Canadian population.
J Med Genet. 2000 Mar;37(3):225-7., [PMID:10777368]

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552 The proportion of patients homozygous for F508 remains quite constant between the three age groups, whereas there is a decline in that of the patients carrying the 621+1G→T/ F508 genotype and an increase of those having a F508/A455E or 621+1G→T/A455E genotype. Login to comment
554 The A455E mutation group contains all the patients with that mutation, independently of the second mutation composing their genotype. Login to comment
555 The CF patients carrying the 621+1G→T mutation, but not A455E, were included in a unique group. Login to comment
556 Patients homozygous or compound heterozygous for the F508 mutation, without the 621+1G→T or the A455E mutation, were grouped together. Login to comment
557 We observed an increase of A455E and a depletion of 621+1G→T at older age groups, whereas the frequency of the F508 mutation stayed constant (table 1B). Login to comment
559 The Kaplan-Meier survival analysis could not be performed considering the three mutations because there were no dead patients in the A455E group. Login to comment
564 The F508 and 621+1G→T alleles are known to be severe mutations conferring pancreatic insuYciency when they are combined with another severe mutation.4 8 9 The A455E allele is a mild mutation associated with pancreatic suYciency and exerts a dominant eVect on the severe mutations. Login to comment
565 Compound heterozygotes for the A455E mutation have a milder pulmonary disease, no meconium ileus, and no late complications, such as diabetes and liver cirrhosis.2 Therefore, since pulmonary insuYciency is the major cause of mortality in cystic fibrosis, it is not unexpected that no CF patients carrying the A455E mutation have died unlike the 13% of those with two severe mutations. Login to comment
570 SYLVAIN R RIVARD* CHRISTIAN ALLARD† JEAN-PIERRE LEBLANC† MARCEL MILOT† GERVAIS AUBIN† FERNAND SIMARD† CLAUDE FÉREC‡ MARC DE BRAEKELEER†§¶ *Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Canada Table 1 Distribution of cystic fibrosis patients diagnosed before the age of 5 by age groups in Saguenay-Lac-Saint-Jean, (A) by genotype, (B) by mutation 0-10 years 10.1-20 years Over 20 years All ages No % No % No % No % (A) Genotype F508/ F508 15 (1) 40.5 21 (2) 36.2 18 (3) 42.9 54 (6) 39.4 F508/621+1G→T 12 (1) 32.4 16 (1) 27.6 10 (1*) 23.8 38 (3*) 27.7 F508/A455E 1 2.7 6 10.3 5 11.9 12 8.8 F508/I148T 1 2.7 1 1.7 2 1.5 F508/Y1092X 3 (1) 5.2 1 2.4 4 (1) 2.9 F508/Q890X 1 2.4 1 0.7 F508/R1158X 1 2.4 1 0.7 621+1G→T/621+1G→T 2 (1) 5.4 4 6.9 1 2.4 7 (1) 5.1 621+1G→T/A455E 1 2.7 4 6.9 3 7.1 8 5.8 621+1G→T/711+1G→T 2 (1) 5.4 2 (1) 3.4 4 (2) 2.9 621+1G→T/Y1092X 1 2.7 1 0.7 621+1G→T/S489X 1 2.7 1 0.7 621+1G→T/G85E 1 (1) 1.7 1 (1) 2.4 2 (2) 1.5 A455E/R117C 1 2.7 1 0.7 N1303K/I148T 1 2.4 1 0.7 Total 37 58 42 137 Death (4) 10.8 (6) 10.3 (5*) 11.9 (15*) 10.9 (B) Mutation F508 16 (1) 43.2 25 (3) 43.1 21 (3) 51.2 62 (7) 45.6 621+1G→T 18 (3) 48.6 23 (3) 39.7 12 (2*) 29.3 53 (8*) 39.0 A455E 3 8.1 10 17.2 8 19.5 21 15.4 Total 37 58 41 136 Death (4) 10.8 (6) 10.3 (5*) (12.2) (15*) (11.0) ( ): Number of deaths. Login to comment
573 1 0.8 0.6 0.4 0.2 0 50 Age (y) A455E mutation ∆F508 mutation 621 + 1G T mutation Cumulativesurvival 0 40302010 Letters †Clinique de Fibrose Kystique, Complexe Hospitalier de la Sagamie, Chicoutimi, Canada ‡Établissement de Transfusion Sanguine de Bretagne Occidentale (ETSBO), Brest, France §Institut National d`Etudes Démographiques, Paris, France ¶Laboratoire d`Anthropologie et de Démographie Génétiques, Faculté des Sciences de l`Homme, Université Victor Segalen Bordeaux 2, 3ter Place de la Victoire, F-33076 Bordeaux Cedex, France 1 Boat TF, Welsh MJ, Beaudet AL. Cystic fibrosis. Login to comment
576 New York: McGraw-Hill, 1989:2649-80. 2 De Braekeleer M, Allard C, Leblanc JP, Simard F, Aubin G. Genotype-phenotype correlation in cystic fibrosis patients compound heterozygous for the A455E mutation. Login to comment

[hide] Future pharmacological treatment of cystic fibrosi... Respiration. 2000;67(4):351-7. Zeitlin PL
Future pharmacological treatment of cystic fibrosis.
Respiration. 2000;67(4):351-7., [PMID:10940786]

Abstract [show]
Cystic fibrosis (CF) is an autosomal recessive disorder that is caused by over 850 different mutations in the CF gene. It is useful to group these mutations according to the defect that results in the CFTR mRNA or protein. New pharmacological treatments targeted towards specific mutations that are relatively common are being developed. Class I mutations do not produce CFTR protein because of a premature stop signal in the CFTR DNA. These null mutations can be corrected by certain aminoglycosides which cause the aberrant stop signal to be skipped. Mutations leading to a CFTR protein that attains an unstable structure shortly after translation in the endoplasmic reticulum form class II. Class II mutations can be restored to the protein trafficking pathway by manipulation of chaperone protein/CFTR interactions with chemical chaperones or drugs that affect gene regulation such as the butyrates. Production of a CFTR with reduced Cl(-) transport on the basis of abnormal regulation of the chloride channel is the basis of class III. Genistein can overcome this block in regulation. Mutations that partially reduce chloride conductance through CFTR (class IV) can be stimulated with milrinone, which is a phosphodiesterase inhibitor. Finally, mutations that lead to a severe reduction in normal CFTR protein form class V. Increased levels of CFTR could be generated with the butyrates or supplemented with gene therapy. Although most of the reported mutations in CFTR are rare and unclassified, it may be possible to use genotype-phenotype correlations to determine the best approach.

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22 Examples of CFTR mutations organized by classification of the defect in CFTR biosynthesis Type Genotype Phenotype Defect Cell diagram Drugs that may improve phenotype G542X 621+1 G → T 3905insT W1282X R553X 1717-1 G → A PI no CFTR protein no cell surface chloride transport gentamicin G418 Class II [64] 'F508 N1303K (P574H)a (A455E)a PI defective CFTR processing defective CFTR trafficking no cell surface chloride transport chemical chaperones CPX phenylbutyrate deoxyspergualin Class III [64] G551D G551S PI defective chloride channel regulation reduced or absent cell surface chloride transport genistein pyrophosphate Class IV [64, 66] R117H R334W G314E R347P ('F508)a P574H PS reduced chloride conductance reduced levels of cell surface chloride transport genistein milrinone phenylbutyrate Class V [64] 3849+10 kb C → T 2789+5 G → A 3272-26 A → G A455E 3120+1 G → A 1811+1.6 kb A → G 5Tb PS normal CFTR channels reduced numbers of normal CFTR reduced cell surface chloride transport genistein milrinone phenylbutyrate a Some mutants have features of more than one class of defect. Login to comment

[hide] Mutations of the cystic fibrosis gene, but not cat... Am J Gastroenterol. 2000 Aug;95(8):2061-7. Ockenga J, Stuhrmann M, Ballmann M, Teich N, Keim V, Dork T, Manns MP
Mutations of the cystic fibrosis gene, but not cationic trypsinogen gene, are associated with recurrent or chronic idiopathic pancreatitis.
Am J Gastroenterol. 2000 Aug;95(8):2061-7., [PMID:10950058]

Abstract [show]
OBJECTIVE: We investigated whether mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene and cationic trypsinogen gene are associated with recurrent acute, or chronic idiopathic pancreatitis. METHODS: Twenty patients with idiopathic pancreatitis (11 women, nine men; mean age, 30 yr) were studied for the presence of a CFTR mutation by screening the genomic DNA for more than 30 mutations and variants in the CFTR gene. Selected mutations of the cationic trypsinogen gene were screened by Afl III restriction digestion or by a mutation-specific polymerase chain reaction (PCR). In each patient exons 1, 2, and 3 of the cationic trypsinogen gene were sequenced. Patients with a CFTR mutation underwent evaluation of further functional electrophysiological test (intestinal current measurement). RESULTS: No mutation of the cationic trypsinogen gene was detected. A CFTR mutation was detected in 6/20 (30.0%) patients. Three patients (15.0%) had a cystic fibrosis (CF) mutation on one chromosome (deltaF508, I336K, Y1092X), which is known to cause phenotypical severe cystic fibrosis. One patient was heterozygous for the 5T allele. In addition, two possibly predisposing CFTR variants (R75Q, 1716G-->A) were detected on four patients, one of these being a compound heterozygous for the missense mutation I336K and R75Q. No other family member (maternal I336K; paternal R75Q; sister I1336K) developed pancreatitis. An intestinal current measurement in rectum samples of patients with a CFTR mutation revealed no CF-typical constellations. CONCLUSIONS: CFTR mutations are associated with recurrent acute, or chronic idiopathic pancreatitis, whereas mutations of the cationic trypsinogen mutation do not appear to be a frequent pathogenetic factor.

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53 Using the ARMS technology (elucigene CF20, Zeneca Diagnostics, Oxfordshire, UK) all samples were tested additionally for the mutations E60X, R347P, A455E, 1078delT, 2183AA3G, G542X, G551D, N1303K, W1282X, 1717-1G3A, R553X, 621ϩ1G3T, R117H, R1162X, 3849ϩ10kbC3T, R334W, S1251N, and 3659delC. Login to comment

[hide] Prenatal detection by real-time quantitative PCR a... Clin Chem. 2000 Sep;46(9):1417-20. Costes B, Girodon E, Vidaud D, Flori E, Ardalan A, Conteville P, Fanen P, Niel F, Vidaud M, Goossens M
Prenatal detection by real-time quantitative PCR and characterization of a new CFTR deletion, 3600+15kbdel5.3kb (or CFTRdele19).
Clin Chem. 2000 Sep;46(9):1417-20., [PMID:10973878]

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51 The mutations tested were S549N, S549R, R553X, G551D, V520F, ⌬I507, ⌬F508, Q493X, 1717-1G3A, G542X, R560T, R347P, R347H, 3849ϩ4A3G, W1282X, R334W, 1078delT, 3849ϩ10kbC3T, R1162X, N1303K, 3659delC, 3905insT, A455E, R117H, Y122X, 2183AA3G, 2789ϩ5G3A, 1898ϩ1G3A, 621ϩ1G3T, 711ϩ1G3T, and G85E. Login to comment

[hide] Mutation in the gene responsible for cystic fibros... JAMA. 2000 Oct 11;284(14):1814-9. Wang X, Moylan B, Leopold DA, Kim J, Rubenstein RC, Togias A, Proud D, Zeitlin PL, Cutting GR
Mutation in the gene responsible for cystic fibrosis and predisposition to chronic rhinosinusitis in the general population.
JAMA. 2000 Oct 11;284(14):1814-9., 2000-10-11 [PMID:11025834]

Abstract [show]
CONTEXT: Chronic rhinosinusitis (CRS) is a common condition in the US general population, yet little is known about its underlying molecular cause. Chronic rhinosinusitis is a consistent feature of the autosomal recessive disorder cystic fibrosis (CF). OBJECTIVE: To determine whether mutations in the cystic fibrosis transmembrane regulator (CFTR) gene, which is responsible for CF, predispose to CRS. DESIGN: Case-control study conducted from 1996 to 1999 in which the DNA of CRS patients and controls was typed for 16 mutations that account for 85% of CF alleles in the general population. Chronic rhinosinusitis patients with 1 CF mutation were evaluated for a CF diagnosis by sweat chloride testing, nasal potential difference measurement, and DNA analysis for additional mutations. SETTING: Otolaryngology-head and neck clinic of a US teaching hospital. PARTICIPANTS: One hundred forty-seven consecutive adult white patients who met stringent diagnostic criteria for CRS and 123 CRS-free white control volunteers of similar age range, geographic region, and socioeconomic status. MAIN OUTCOME MEASURES: Presence of CF mutations by DNA analysis among CRS patients vs controls. RESULTS: Eleven CRS patients were found to have a CF mutation (DeltaF508, n = 9; G542X, n = 1; and N1303K, n = 1). Diagnostic testing excluded CF in 10 of these patients and led to CF diagnosis in 1. Excluding this patient from the analyses, the proportion of CRS patients who were found to have a CF mutation (7%) was significantly higher than in the control group (n = 2 [2%]; P =.04, both having DeltaF508 mutations). Furthermore, 9 of the 10 CF carriers had the polymorphism M470V, and M470V homozygotes were overrepresented in the remaining 136 CRS patients (P =.03). CONCLUSION: These data indicate that mutations in the gene responsible for CF may be associated with the development of CRS in the general population. JAMA. 2000;284:1814-1819.

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30 Analysis of CFTR Genes Genomic DNA samples extracted from the blood of participants were screened for 16 mutations (R117H, 621+1G→T, R334W, R347P, A455E, ⌬I507, ⌬F508, 1717-1 G→A, G542X, S549N, G551D, R553X, R560T, 3849+10 Kb C→T, W1282X, and N1303K) that account for 85% of CF alleles in the white population using the multiplex reverse dot hybridization system (Roche Molecular Systems, Alameda, Calif).16,17 This test also identified the 5T, 7T, and 9T variants of the splice acceptor site in intron 8 and F508C, I507V, and I506V (exon 10) polymorphisms of the CFTR gene. Login to comment

[hide] Type I, II, III, IV, and V cystic fibrosis transme... Curr Opin Pulm Med. 2000 Nov;6(6):521-9. Choo-Kang LR, Zeitlin PL
Type I, II, III, IV, and V cystic fibrosis transmembrane conductance regulator defects and opportunities for therapy.
Curr Opin Pulm Med. 2000 Nov;6(6):521-9., [PMID:11100963]

Abstract [show]
Recent advances in cellular and molecular biology have furthered the understanding of several genetic diseases, including cystic fibrosis. Mutations that cause cystic fibrosis are now understood in terms of the specific molecular consequences to the cystic fibrosis transmembrane conductance regulator (CFTR) protein expression and function. This knowledge has spawned interest in the development of therapies aimed directly at correcting the defective CFTR itself. In this article, we review the molecular defect underlying each recognized class of CFTR mutation and the potential therapies currently under investigation. Opportunities for protein-repair therapy appear to be vast and range from naturally occurring compounds, such as isoflavonoids, to pharmaceuticals already in clinical use, including aminoglycoside antibiotics, butyrate analogues, phosphodiesterase inhibitors, and adenosine nucleotides. Future therapies may resemble designer compounds like benzo[c]quinoliziniums or take the form of small peptide replacements. Given the heterogeneity and progressive nature of cystic fibrosis, however, optimal benefit from protein-repair therapy will most likely require the initiation of combined therapies early in the course of disease to avoid irreparable organ damage.

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37 Molecular fate of CFTR protein Type of genetic defect and example Class-specific potential therapeutic approach Specific clinical examples I No synthesis Nonsense G542X Frameshift 394delTT Splice junction 1717-1G→A Aminoglycoside readthrough of premature termination site Gentamicin II Trafficking block AA deletion ∆F508 Missense N1303K Manipulation of intracellular folding environment (chemical or molecular chaperones) Phenylbutyrate, CPX III Block in regulation Missense G551D Stimulation of membrane localized mutant channel Genistein, MPB- compounds IV Altered conductance Missense R117H Augmentation of mutant channel conductance Milrinone, adenosine nucleotides V Reduced synthesis of normal protein Missense A455E Alternative splicing 3849+10kbC→T Maximal activation of decreased but functionally normal channels Stimulation of mRNA and protein synthesis ? Login to comment
116 Through this mechanism, adenosine indirectly activates wild-type as well as several surface-localized mutant CFTR channels including R117H, A455E, and G1349D. Login to comment
124 Missense mutations that belong to this class include P574H and A455E. Login to comment

[hide] Improved detection of cystic fibrosis mutations in... Genet Med. 2001 May-Jun;3(3):168-76. Heim RA, Sugarman EA, Allitto BA
Improved detection of cystic fibrosis mutations in the heterogeneous U.S. population using an expanded, pan-ethnic mutation panel.
Genet Med. 2001 May-Jun;3(3):168-76., [PMID:11388756]

Abstract [show]
PURPOSE: To determine the comparative frequency of 93 CFTR mutations in U.S. individuals with a clinical diagnosis of cystic fibrosis (CF). METHODS: A total of 5,840 CF chromosomes from Caucasians, Ashkenazi Jews, Hispanics, African Americans, Native Americans, Asians, and individuals of mixed race were analyzed using a pooled ASO hybridization strategy. RESULTS: Sixty-four mutations provided a sensitivity of 70% to 95% in all ethnic groups except Asians, and at least 81% when the U.S. population was considered as a whole. CONCLUSIONS: For population-based carrier screening for CF in the heterogeneous U.S. population, which is characterized by increasing admixture, a pan-ethnic mutation panel of 50 to 70 CFTR mutations may provide a practical test that maximizes sensitivity.

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110 This difference is unlikely to be due to ascertainment, since the observed frequency of ⌬F508 (29%) is equivalent to the frequency of 30% reported by Abeliovich et al.16 In this study, the detection of an additional three mutations was required to bring the overall detection rate to 95.4% (A455E, R553X, and D1152H). Login to comment

[hide] Evidence that systemic gentamicin suppresses prema... Am J Respir Crit Care Med. 2001 Jun;163(7):1683-92. Clancy JP, Bebok Z, Ruiz F, King C, Jones J, Walker L, Greer H, Hong J, Wing L, Macaluso M, Lyrene R, Sorscher EJ, Bedwell DM
Evidence that systemic gentamicin suppresses premature stop mutations in patients with cystic fibrosis.
Am J Respir Crit Care Med. 2001 Jun;163(7):1683-92., [PMID:11401894]

Abstract [show]
Here we report the effects of gentamicin treatment on cystic fibrosis transmembrane regulator (CFTR) production and function in CF airway cells and patients with CF with premature stop mutations. Using immunocytochemical and functional [6-methoxy-N- (3-sulfopropyl) quinolinium (SPQ)-based] techniques, ex vivo exposure of airway cells from stop mutation CF patients led to the identification of surface-localized CFTR in a dose-dependent fashion. Next, five patients with CF with stop mutations and five CF control subjects were treated with parenteral gentamicin for 1 wk, and underwent repeated in vivo measures of CFTR function (nasal potential difference [PD] measurements and sweat chloride [Cl(-)] testing). During the treatment period, the number of nasal PD readings in the direction of Cl(-) secretion was increased approximately 3-fold in the stop mutation patient group compared with controls (p < 0.001), and four of five stop mutation patients with CF had at least one reading during gentamicin treatment with a Cl(-) secretory response of more than -5 mV (hyperpolarized). A response of this magnitude was not seen in any of the CF control subjects (p < 0.05). In an independent series of experiments designed to test the ability of repeat nasal PDs to detect wild-type CFTR function, evidence of Cl(-) secretion was seen in 88% of control (non-CF) nasal PDs, and 71% were more than -5 mV hyperpolarized. Together, these results suggest that gentamicin treatment can suppress premature stop mutations in airway cells from patients with CF, and produce small increases in CFTR Cl(-) conductance (as measured by the nasal PD) in vivo.

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196 Reports indicate that some CF patients with uncommon alleles (i.e., conduction mutants such as R117H or R334W, or the uncommon A455E allele) may have abnormally elevated sweat [Cl- ] values diagnostic of CF but lower than those of the general CF population (9, 25-27). Login to comment

[hide] Aerosol and lobar administration of a recombinant ... Hum Gene Ther. 2001 Jul 20;12(11):1369-82. Joseph PM, O'Sullivan BP, Lapey A, Dorkin H, Oren J, Balfour R, Perricone MA, Rosenberg M, Wadsworth SC, Smith AE, St George JA, Meeker DP
Aerosol and lobar administration of a recombinant adenovirus to individuals with cystic fibrosis. I. Methods, safety, and clinical implications.
Hum Gene Ther. 2001 Jul 20;12(11):1369-82., 2001-07-20 [PMID:11485629]

Abstract [show]
Cystic fibrosis (CF), an autosomal recessive disorder resulting from mutations in the cystic fibrosis trans-membrane conductance regulator (CFTR) gene, is the most common lethal genetic illness in the Caucasian population. Gene transfer to airway epithelium, using adenoviruses containing normal CFTR cDNA, leads to transient production of CFTR mRNA and, in some studies, to correction of the airway epithelial ion transport defect caused by dysfunctional CFTR. Inflammatory responses to the adenoviral vector have been reported, particularly at high viral titers. We evaluated the effects of adenovirus-mediated CFTR gene transfer to airway epithelium in 36 subjects with CF (34 individuals, 2 of whom received two separate doses of vector), 20 by lobar instillation and 16 by aerosol administration. Doses ranged from 8 x 10(6) to 2.5 x 10(10) infective units (IU), in 0.5-log increments. After lobar administration of low doses there were occasional reports of cough, low-grade temperature, and myalgias. At the highest lobar dose (2.5 x 10(9) IU) two of three patients had transient myalgias, fever, and increased sputum production with obvious infiltrates on CT scan. After aerosol administration there were no significant systemic symptoms until the 2.5 x 10(10) IU dose, when both patients experienced myalgias and fever that resolved within 24 hr. There were no infiltrates seen on chest CT scans in any of the patients in the aerosol administration group. There were no consistent changes in pulmonary function tests or any significant rise in serum IgG or neutralizing antibodies in patients from either group. Serum, sputum, and nasal cytokines, measured before and after vector administration, showed no correlation with adenoviral dose. Gene transfer to lung cells was inefficient and expression was transient. Cells infected with the vector included mononuclear inflammatory cells as well as cuboidal and columnar epithelial cells. In summary, we found no consistent immune response, no evidence of viral shedding, and no consistent change in pulmonary function in response to adenovirus-mediated CFTR gene transfer. At higher doses there was a mild, nonspecific inflammatory response, as evidenced by fevers and myalgias. Overall, vector administration was tolerated but transfer of CFTR cDNA was inefficient and transgene expression was transient for the doses and method of administration used here.

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338 Further supporting the idea that only a small percentage of cells need be corrected to overcome the life-threatening pulmonary consequencesof CF is the fact that the A455E mutation, which is associated with approximately 5% normal CFTR function, appears to confer a mild pulmonary phenotype (Gan et al., 1995; Davies et al., 1998). Login to comment

[hide] Intron-8 polythymidine sequence in Australasian in... Eur Respir J. 2001 Jun;17(6):1195-200. Massie RJ, Poplawski N, Wilcken B, Goldblatt J, Byrnes C, Robertson C
Intron-8 polythymidine sequence in Australasian individuals with CF mutations R117H and R117C.
Eur Respir J. 2001 Jun;17(6):1195-200., [PMID:11491164]

Abstract [show]
Compound heterozygotes for a severe cystic fibrosis transmembrane conductance regulator (CFTR) mutation and the R117H or R117C mutation (R117H/C) have clinical presentations that vary from classic cystic fibrosis (CF) to an incidental genetic finding. The aim of this study was to assess the influence of the intron-8 polythvmidine sequence (IVS8) on the relationship between genotype and phenotype of individuals with R117H/C. All individuals with R117H/C known to CF clinics in Australia and New Zealand were retrospectively studied by collecting information on genotype, age, pancreatic status, sweat electrolytes, sputum microbiology and pulmonary function. Forty-one individuals (39 with R117H and two with R117C), 16 on an IVS8-5T background and 25 on an IVS8-7T background were identified. Twelve individuals presented clinically, four were siblings of known R117H/C compound heterozygotes and 25 were detected by newborn screening. Eleven of 14 of the IVS8-5T group (78%) with sweat chloride results available had sweat CI > 60 mmol x L(-1) compared to 5 (20%) of the R117H/7T group (Chi-squared=10.4, p=0.001). Two were pancreatic insufficient, both IVS8-5T. Two IVS8-5T individuals have recently died (aged 43 and 19) and of the 14 surviving IVS8-5T group, 11 (79%) are symptomatic compared to eight (32%) of the IVS8-7T individuals (Chi-squared=6.1, p=0.01). In conclusion, most individuals with R117H/C on a IVS8-5T background have an elevated sweat chloride and clinical cystic fibrosis, which in some cases is severe. Most individuals with R117H/C on an IVS8-7T background do not have clinical cystic fibrosis but should be followed for the development of clinical disease.

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41 Infants with a positive (w60 mmol?L-1 ) or borderline (40 - 60 mmol?L-1 ) sweat chloride and in whom there is an unidentified mutation are referred for an extended mutation analysis which includes: DF508, R117H, G551D, A455E, G542X, N1303K, W1282X, 1717-1, R560T, R347P, R334W, R1162X, S549N, 621z1, 3849z10CwT, and the IVS8 polythymidine sequence. Login to comment

[hide] A combined analysis of the cystic fibrosis transme... Mol Biol Evol. 2001 Sep;18(9):1771-88. Chen JM, Cutler C, Jacques C, Boeuf G, Denamur E, Lecointre G, Mercier B, Cramb G, Ferec C
A combined analysis of the cystic fibrosis transmembrane conductance regulator: implications for structure and disease models.
Mol Biol Evol. 2001 Sep;18(9):1771-88., [PMID:11504857]

Abstract [show]
Over the past decade, nearly 1,000 variants have been identified in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in classic and atypical cystic fibrosis (CF) patients worldwide, and an enormous wealth of information concerning the structure and function of the protein has also been accumulated. These data, if evaluated together in a sequence comparison of all currently available CFTR homologs, are likely to refine the global structure-function relationship of the protein, which will, in turn, facilitate interpretation of the identified mutations in the gene. Based on such a combined analysis, we had recently defined a "functional R domain" of the CFTR protein. First, presenting two full-length cDNA sequences (termed sCFTR-I and sCFTR-II) from the Atlantic salmon (Salmo salar) and an additional partial coding sequence from the eastern gray kangaroo (Macropus giganteus), this study went further to refine the boundaries of the two nucleotide-binding domains (NBDs) and the COOH-terminal tail (C-tail), wherein NBD1 was defined as going from P439 to G646, NBD2 as going from A1225 to E1417, and the C-tail as going from E1418 to L1480. This approach also provided further insights into the differential roles of the two halves of CFTR and highlighted several well-conserved motifs that may be involved in inter- or intramolecular interactions. Moreover, a serious concern that a certain fraction of missense mutations identified in the CFTR gene may not have functional consequences was raised. Finally, phylogenetic analysis of all the full-length CFTR amino acid sequences and an extended set of exon 13--coding nucleotide sequences reinforced the idea that the rabbit may represent a better CF model than the mouse and strengthened the assertion that a long-branch attraction artifact separates the murine rodents from the rabbit and the guinea pig, the other Glires.

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100 Moreover, all of the 11 most common missense mutations or single-amino-acid deletions (i.e., F508del, G551D, N1303K, R117H, R347P, I507del, G85E, R560T, A455E, R334W, and S549N) identified in classic and atypical CF patients worldwide (http://www.genet.sickkids.on.ca/cftr) occur in stringently conserved residues across the 15 CFTR sequences. Login to comment

[hide] [Cystic fibrosis and normal sweat chloride values:... Rev Mal Respir. 2001 Sep;18(4 Pt 1):443-5. Lebecque P, Leal T, Godding V
[Cystic fibrosis and normal sweat chloride values: a case-report].
Rev Mal Respir. 2001 Sep;18(4 Pt 1):443-5., [PMID:11547256]

Abstract [show]
In a suggestive context, normal sweat chloride values (<60 mmol/L) do not always suffice to exclude the diagnosis of CF.CASE-REPORT: A 19-year-old female presented with a diagnosis of bronchiectasis. Her past medical history was noteworthy for the onset of respiratory symptoms in the infancy, colonization of the respiratory tract by Pseudomonas aeruginosa for three years and previous treatment for allergic bronchopulmonary aspergillosis. She was heterozygote for the DeltaF 508 mutation of the CFTR gene. Sweat chloride values were repeatedly normal, ranging from 25 to 46 mmol/L. The diagnosis of CF was confirmed by the identification of a second CFTR mutation (D1152H) and the demonstration of typical nasal potential.CONCLUSION: It is now estimated that approximately 2% of CF patients will present an "atypical" phenotype with sweat chloride values<60 mmol/L. For these patients, the diagnosis can be confirmed by the identification of a CF-causing mutation in each CFTR allele or in vivo demonstration of CFTR dysfunction by nasal potential difference study.

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73 Dans des situations d`hétérozygotie composite, la présence de certaines d`entre elles a pu être associée de manière occasionnelle ou parfois plus consistante avec un taux de chlorure dans la sueur inférieur à 60 voire même (dans de très rares cas) 30 mmol/L. Dans ce singulier petit groupe, figurent notamment les mutations 3 849 + 10kb C→T, A455E, R117H, , R347H, G551S, D1152H. Login to comment

[hide] Mutations of the cystic fibrosis gene in patients ... Am J Gastroenterol. 2001 Sep;96(9):2657-61. Truninger K, Malik N, Ammann RW, Muellhaupt B, Seifert B, Muller HJ, Blum HE
Mutations of the cystic fibrosis gene in patients with chronic pancreatitis.
Am J Gastroenterol. 2001 Sep;96(9):2657-61., [PMID:11569691]

Abstract [show]
OBJECTIVE: Several studies have reported an increased frequency of cystic fibrosis gene mutations in idiopathic but not in alcoholic chronic pancreatitis. The impact of cystic fibrosis gene mutations on the long-term course of chronic pancreatitis has not been analyzed. The aim of our study was to determine the frequency of cystic fibrosis gene mutations in patients with chronic pancreatitis with long-term follow-up and to see whether patients with mutations have a clinically different natural course compared to those without mutations. METHODS: Eighty two patients with chronic pancreatitis and 11 patients with recurrent acute pancreatitis of our well defined pancreatitis cohort were screened for the 31 most common cystic fibrosis gene mutations. The impact of cystic fibrosis gene mutations on the long-term course of chronic pancreatitis was assessed. RESULTS: A cystic fibrosis gene mutation was detected in five of 49 patients with alcoholic chronic pancreatitis (10.2%; 2.3 times the expected frequency) and in three of 14 patients with idiopathic-juvenile chronic pancreatitis (21.4%; 4.8 times the expected frequency). No mutations were found in the remaining patients with chronic pancreatitis of rare causes, hereditary pancreatitis, and recurrent acute pancreatitis. The frequency of pancreatic calcifications was significantly higher in patients with alcoholic chronic pancreatitis without mutations. This result was not confirmed in patients with idiopathic-juvenile chronic pancreatitis. The duration of pain and the frequency of exocrine and endocrine insufficiency was comparable in both subgroups irrespective of the mutation status. CONCLUSION: Our data indicate a significantly increased frequency of cystic fibrosis gene mutations both in patients with alcoholic and idiopathic-juvenile chronic pancreatitis. The natural course was similar in patients with mutations compared to those without mutations.

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56 Using multiplex PCR, 15 genomic fragments were amplified which contain the following mutations: ⌬F508, ⌬I507, Q493X, V520F, 1717-1G3A, G542X, G551D, R553X, R560T, S549R, S549N, 3849 ϩ 10kbC3T, 3849 ϩ 4A3G, R1162X, 3659delC, W1282X, 3905insT, N1303K, G85E, 621 ϩ 1G3T, R117H, Y122X, 711 ϩ 1G3T; 1078delT, R347P, R347H, R334W, A455E, 1898 ϩ 1G3A, 2183AA3G, 2789 ϩ 5G3A. Login to comment

[hide] Perspectives on gene therapy for cystic fibrosis a... BioDrugs. 2001;15(9):615-34. Bigger B, Coutelle C
Perspectives on gene therapy for cystic fibrosis airway disease.
BioDrugs. 2001;15(9):615-34., [PMID:11580305]

Abstract [show]
Since the discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene nearly 12 years ago, cystic fibrosis (CF) has become one of the most intensively investigated monogenetic disorders considered approachable by gene therapy. This has resulted in over 20 clinical trials currently under way, concluded or awaiting approval. Despite the initial promise of gene therapy for CF, and the demonstration of successful gene transfer to the nose and airways of individuals, it has not so far been as effective as initially projected. Here we discuss the rationale behind CF gene therapy and dissect the vast array of literature representing the work that ultimately brought about the current phase I/II clinical trials. In the context of human trials, we review the limitations of current vector systems for CF gene therapy. We come to the conclusion that at present none of the application methods and vector systems are able to achieve the level and persistence of CFTR gene expression in the affected epithelia of CF patients that is required for therapeutic success. We also outline the challenges that must be overcome and describe some of the novel approaches to be taken in order to attain the curative therapy that was originally envisaged for this disease.

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1262 However, human CFTR mutations such as A455E are associated with ~5% CFTR function and confer only a mild pulmonary phenotype. Login to comment

[hide] Analysis of exocrine pancreatic function in cystic... Eur J Clin Invest. 2001 Sep;31(9):796-801. Walkowiak J, Herzig KH, Witt M, Pogorzelski A, Piotrowski R, Barra E, Sobczynska-Tomaszewska A, Trawinska-Bartnicka M, Strzykala K, Cichy W, Sands D, Rutkiewicz E, Krawczynski M
Analysis of exocrine pancreatic function in cystic fibrosis: one mild CFTR mutation does not exclude pancreatic insufficiency.
Eur J Clin Invest. 2001 Sep;31(9):796-801., [PMID:11589722]

Abstract [show]
BACKGROUND: Cystic fibrosis (CF) is the most common cause of exocrine pancreatic insufficiency in childhood. The aim of the present study is to evaluate the correlation between genotype and exocrine pancreatic insufficiency in CF patients. The special emphasis was put on the analysis of mild CFTR mutations. DESIGN: The study comprised 394 CF patients and 105 healthy subjects (HS). Elastase-1 concentrations were measured in all subjects. RESULTS: Severe pancreatic insufficiency was associated with the presence of two CFTR gene mutations (DeltaF508, N1303K, CFTR dele 2,3 (21kb), G542X, 1717-1G-A, R533X, W1282X, 621GT, 2183AAG, R560T, 2184insA and DeltaI507, G551D, 895T) and mild insufficiency with the presence of at least one mutation (R117H, 3171insC, A155P2, 138insL, 296 + 1G-A, E92GK, E217G, 2789 + 5G-A. 3849 + 1kbC-T/3849 + 1kbC-T) genotype resulted in high elastase-1-values. However, in case of patients with genotype DeltaF508/3849 + 10kbC-T, 1717-1GA/3849 + 10kbC-T as well as with DeltaF508/R334W, both high and low elastase-1 concentrations were found. Low E1 values were found in a patient with DeltaF508/R347P genotype. CONCLUSION: Patients who carry two 'severe' mutations develop pancreatic insufficiency, whereas those who carry at least one 'mild' usually remain pancreatic sufficient. However, the presence of one mild mutation does not exclude pancreatic insufficiency.

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86 Kristidis et al. [10] reported that pancreatic insufficiency strongly correlates also with two alleles of DI507, Q493X, G542X, R553X, W1282X, 621 1 1G-T, 1717±1G-A, 556delA, 3659delC, I148T, G480C, V520F and R560T while one or two mutations such as R117H, R334W, A455E, and P574H were correlated with a pancreatic sufficient phenotype. Login to comment

[hide] Gene therapy for cystic fibrosis. J Gene Med. 2001 Sep-Oct;3(5):409-17. Davies JC, Geddes DM, Alton EW
Gene therapy for cystic fibrosis.
J Gene Med. 2001 Sep-Oct;3(5):409-17., [PMID:11601754]

Abstract [show]
Cystic fibrosis (CF) is associated with significant morbidity and mortality, despite significant advances in conventional treatment. The field of gene therapy has progressed rapidly since the cystic fibrosis transmembrane conductance regulator (CFTR) gene was cloned. In this review we discuss current knowledge on the underlying molecular defect in CF, and the progress in gene transfer studies from the early in vitro work through to clinical trials, including the development of endpoints to assess efficacy. We highlight the problems encountered, and likely future directions of the field.

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92 Encouragingly, certain mutations such as A455E, associated with approximately 5% CFTR function, appear to confer a mild pulmonary phenotype [53]. Login to comment
94 However, when considering this issue, it is important to bear in mind that in both the interbred mice and the humans with the A455E genotype, each cell would express low levels of CFTR (5-10%). Login to comment

[hide] Human genetics: lessons from Quebec populations. Annu Rev Genomics Hum Genet. 2001;2:69-101. Scriver CR
Human genetics: lessons from Quebec populations.
Annu Rev Genomics Hum Genet. 2001;2:69-101., [PMID:11701644]

Abstract [show]
The population of Quebec, Canada (7.3 million) contains approximately 6 million French Canadians; they are the descendants of approximately 8500 permanent French settlers who colonized Nouvelle France between 1608 and 1759. Their well-documented settlements, internal migrations, and natural increase over four centuries in relative isolation (geographic, linguistic, etc.) contain important evidence of social transmission of demographic behavior that contributed to effective family size and population structure. This history is reflected in at least 22 Mendelian diseases, occurring at unusually high prevalence in its subpopulations. Immigration of non-French persons during the past 250 years has given the Quebec population further inhomogeneity, which is apparent in allelic diversity at various loci. The histories of Quebec's subpopulations are, to a great extent, the histories of their alleles. Rare pathogenic alleles with high penetrance and associated haplotypes at 10 loci (CFTR, FAH, HBB, HEXA, LDLR, LPL, PAH, PABP2, PDDR, and SACS) are expressed in probands with cystic fibrosis, tyrosinemia, beta-thalassemia, Tay-Sachs, familial hypercholesterolemia, hyperchylomicronemia, PKU, oculopharyngeal muscular dystrophy, pseudo vitamin D deficiency rickets, and spastic ataxia of Charlevoix-Saguenay, respectively) reveal the interpopulation and intrapopulation genetic diversity of Quebec. Inbreeding does not explain the clustering and prevalence of these genetic diseases; genealogical reconstructions buttressed by molecular evidence point to founder effects and genetic drift in multiple instances. Genealogical estimates of historical meioses and analysis of linkage disequilibrium show that sectors of this young population are suitable for linkage disequilibrium mapping of rare alleles. How the population benefits from what is being learned about its structure and how its uniqueness could facilitate construction of a genomic map of linkage disequilibrium are discussed.

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242 Three mutations ( F508, 60%; 621 + 1, 25.5%; A455E, 8.5%) account for 94% of CF chromosomes in the SLSJ population, with 42% of probands being homoallelic (50). Login to comment
245 The A455E allele, prominent in SLSJ, has a mild effect and confers pancreatic sufficiency (138). Login to comment
246 Estimates of inbreeding and kinship coefficients in the SLSJ families harboring F508, 621 + 1, and A455E alleles are somewhat higher than in the general population, and a putative common ancestor for carriers of the A455E allele is claimed (40). Login to comment

[hide] Genetic and clinical features of false-negative in... Acta Paediatr. 2002;91(1):82-7. Padoan R, Genoni S, Moretti E, Seia M, Giunta A, Corbetta C
Genetic and clinical features of false-negative infants in a neonatal screening programme for cystic fibrosis.
Acta Paediatr. 2002;91(1):82-7., [PMID:11883825]

Abstract [show]
A study was performed on the delayed diagnosis of cystic fibrosis (CF) in infants who had false-negative results in a neonatal screening programme. The genetic and clinical features of false-negative infants in this screening programme were assessed together with the efficiency of the screening procedure in the Lombardia region. In total, 774,687 newborns were screened using a two-step immunoreactive trypsinogen (IRT) (in the years 1990-1992), IRT/IRT + delF508 (1993-1998) or IRT/IRT + polymerase chain reaction (PCR) and oligonucleotide ligation assay (OLA) protocol (1998-1999). Out of 196 CF children born in the 10 y period 15 were false negative on screening (7.6%) and molecular analysis showed a high variability in the genotypes. The cystic fibrosis transmembrane regulator (CFTR) gene mutations identified were delF508, D1152H, R1066C, R334W, G542X, N1303K, F1052V, A120T, 3849 + 10kbC --> T, 2789 + 5G --> A, 5T-12TG and the novel mutation D110E. In three patients no mutation was identified after denaturing gradient gel electrophoresis of the majority of CFTR gene exons. Conclusion: The clinical phenotypes of CF children diagnosed by their symptoms at different ages were very mild. None of them presented with a severe lung disease. The majority of them did not seem to have been damaged by the delayed diagnosis. The combination of IRT assay plus genotype analysis (1998-1999) appears to be a more reliable method of detecting CF than IRT measurement alone or combined with only the delF508 mutation.

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34 It was initially performed by polyacrylamide gel electrophoretic (PAGE) analysis for the delF508 mutation, and later by polymerase chain reaction (PCR) and oligonucleotide ligation assay (OLA) (31 mutations: G85E, 621 ‡ 1G ® T, R117H, Y122X, 711 ‡ 1G ® T, 1078delT, R347P, R347H, R334W, A455E, 1898 ‡ 1G ® A, 2183-AA ® G, 2789 ‡ 5G ® A, DelF508, I507del, Q493X, V520F, 1717-1G ® A, G542X, G551D, R553X, R560T, S549R, S549N, 3849 ‡ 10kbC ® T, 3849 ‡ 4A ® G, R1162X, 3659delC, W1282X, 3905insT, N1303K) (14). Login to comment

[hide] Mutations of the cystic fibrosis gene and intermed... Am J Respir Crit Care Med. 2002 Mar 15;165(6):757-61. Lebecque P, Leal T, De Boeck C, Jaspers M, Cuppens H, Cassiman JJ
Mutations of the cystic fibrosis gene and intermediate sweat chloride levels in children.
Am J Respir Crit Care Med. 2002 Mar 15;165(6):757-61., 2002-03-15 [PMID:11897640]

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The incidence of mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in children with intermediate sweat chloride levels is unknown. The results of 2,349 sweat tests performed at two Belgian university hospitals were reviewed. Intermediate chloride concentrations were observed in 98 subjects (4.2%), 68 being younger than 18 years of age. Forty-three children could be traced and their parents agreed to take part in the study. Exhaustive analysis of the CFTR gene disclosed a total of 24 putative mutations (27.9%). Three subjects were found to carry only one CFTR mutation, whereas 10 harbored one mutation on both CFTR genes. These 10 children were investigated in detail. At the time of writing, the mean age (+/-SD) of this group is 8.9 years (+/-4.2 years). Nine children are pancreatic sufficient. Three have been asymptomatic for more than two years, whereas the others display, to different degrees, clinical features suggestive of CF. The sweat chloride concentration is slightly higher in this group (39.4 +/- 5.4 mM) than in subjects without CFTR mutation (35.2 +/- 4.4 mM, p < 0.05). The nasal potential difference was abnormal in five of the nine subjects tested. In this study, 23% of children displaying intermediate sweat chloride levels were found to carry a putative mutation on both CFTR genes.

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69 In the latter study, however, data are likely influenced by the frequency of the A455E mutation in the Dutch population. Login to comment

[hide] Towards the pharmacogenomics of cystic fibrosis. Pharmacogenomics. 2002 Jan;3(1):75-87. Sangiuolo F, D'Apice MR, Bruscia E, Lucidi V, Novelli G
Towards the pharmacogenomics of cystic fibrosis.
Pharmacogenomics. 2002 Jan;3(1):75-87., [PMID:11966405]

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Cystic fibrosis (CF) is the most common lethal recessive genetic disease affecting children in Europe and the US. CF is a multiorgan disease and may present a variety of clinical symptoms, like chronic obstructive lung disease, exocrine pancreatic insufficiency (PI) and elevated sweat chloride concentration. CF mutations have also been found in other related clinical diseases such as congenital bilateral absence of the vas deferens (CBAVD), disseminated bronchiectasis and chronic pancreatitis. These clinical overlaps pose etiopathogenetic, diagnostic and therapeutic questions. Despite stunning advances in genomic technologies and drug discovery, drug therapy often improves disease symptoms but does not cure the disease. One of the main causes of this failure in CF cure may be attributable to genetic variability and to the scarce knowledge of CF biochemistry. Therefore, knowing the genotype of a patient might help improve drug efficacy, reduce toxicity and suggests innovative genomic-based therapy approaches.

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111 Gentamicin Neomicin (G418) Class II Mutations that fail to be properly processed to a matureglycosylatedform and transported to the apical membrane ∆F508 N1303K P574H A455E PI Defective CFTR processing and trafficking. Login to comment
115 3849 + 10 kb C→→→→T 2789 + 5 G→→→→A 3272-26 A→→→→G A455E 3120 +1 G→→→→A 1811 + 1.6 kb A→→→→G 5T PS Normal CFTR channnels Reduced numbers of normal CFTR Reduced cell surface chloride transport Genistein Milrinone Phenylbutyrate Class VI Nonsense or frameshift mutations causing a 70-100 bp truncation of the C-terminus of the CFTR mutations that impair regulation of other types of ion channels. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... Clin Exp Allergy. 2002 May;32(5):756-61. Eaton TE, Weiner Miller P, Garrett JE, Cutting GR
Cystic fibrosis transmembrane conductance regulator gene mutations: do they play a role in the aetiology of allergic bronchopulmonary aspergillosis?
Clin Exp Allergy. 2002 May;32(5):756-61., [PMID:11994102]

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BACKGROUND: Previous work suggests that cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations may be implicated in the aetiology of allergic bronchopulmonary aspergilosis (ABPA). OBJECTIVE: To compare the frequency of CF gene mutations in asthmatics with ABPA of varying severity with asthmatics who were skin prick test (SPT)-positive to Aspergillus fumigatus (Af) without evidence of ABPA and asthmatics SPT-negative to Af. METHODS: Thirty-one Caucasian patients with ABPA were identified, together with asthmatics SPT positive to Af without evidence of ABPA (n = 23) and SPT negative to Af (n = 28). Genomic DNA was tested for 16 CF mutations accounting for approximately 85% of CF alleles in Caucasian New Zealanders. RESULTS: Four (12.9%) ABPA patients were found to be carriers of a CF mutation (DeltaF508 n = 3, R117H n = 1), one (4.3%) asthmatic SPT positive to Af without ABPA (DeltaF508), and one (3.6%) asthmatic SPT negative to Af (R117H). All patients with a CF mutation had normal sweat chloride (< 40 mM). There was no significant difference between the frequency of CF mutations in the ABPA patients and asthmatics without ABPA. However, the frequency of CF mutations in the ABPA patients was significantly different (P = 0.0125) to the expected carrier rate in the general population. CONCLUSION: These results lend further support to a possible link between CF mutations and ABPA.

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53 Cystic ®brosis mutation analysis Genomic DNA samples were screened for 16 CF mutations utilizing allelic-speci®c oligonucleotide (ASO) hybridization; ÁF508, ÁI507, R117H, W1282X, 621 IG3T, R334W, R347P, A455E, 1717-IG3A, G542X, 5549N, G551D, R553X, R560T, N1303K and 3849 10KC3T. Login to comment

[hide] Predictors of deterioration of lung function in cy... Pediatr Pulmonol. 2002 Jun;33(6):483-91. Schaedel C, de Monestrol I, Hjelte L, Johannesson M, Kornfalt R, Lindblad A, Strandvik B, Wahlgren L, Holmberg L
Predictors of deterioration of lung function in cystic fibrosis.
Pediatr Pulmonol. 2002 Jun;33(6):483-91., [PMID:12001283]

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The severity of lung disease in cystic fibrosis (CF) may be related to the type of mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and to environmental and immunological factors. Since pulmonary disease is the main determinant of morbidity and mortality in CF, it is important to identify factors that can explain and predict this variation. The aim of this longitudinal study of the whole Swedish CF population over age 7 years was to correlate genetic and clinical data with the rate of decline in pulmonary function. The statistical analysis was performed using the mixed model regression method, supplemented with calculation of relative risks for severe lung disease in age cohorts.The severity of pulmonary disease was to some extent predicted by CFTR genotype. Furthermore, the present investigation is the first long-term study showing a significantly more rapid deterioration of lung function in patients with concomitant diabetes mellitus. Besides diabetes mellitus, pancreatic insufficiency and chronic Pseudomonas colonization were found to be negative predictors of pulmonary function. In contrast to several other reports, we found no significant differences in lung function between genders. Patients with pancreatic sufficiency have no or only a slight decline of lung function with age once treatment is started, but an early diagnosis in this group is desirable.

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121 TABLE 3CFTR Mutations Associated With Pancreatic Sufficiency in Swedish CF Population Y109C S549I/S549I Y109N S945L R117C N1088D À R75Q R117H G1244E L206W 711 þ 3A !G T338I 1249 À 5A !G A455E 2789 þ 5G ! Login to comment

[hide] Cystic fibrosis: a worldwide analysis of CFTR muta... Hum Mutat. 2002 Jun;19(6):575-606. Bobadilla JL, Macek M Jr, Fine JP, Farrell PM
Cystic fibrosis: a worldwide analysis of CFTR mutations--correlation with incidence data and application to screening.
Hum Mutat. 2002 Jun;19(6):575-606., [PMID:12007216]

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Although there have been numerous reports from around the world of mutations in the gene of chromosome 7 known as CFTR (cystic fibrosis transmembrane conductance regulator), little attention has been given to integrating these mutant alleles into a global understanding of the population molecular genetics associated with cystic fibrosis (CF). We determined the distribution of CFTR mutations in as many regions throughout the world as possible in an effort designed to: 1) increase our understanding of ancestry-genotype relationships, 2) compare mutational arrays with disease incidence, and 3) gain insight for decisions regarding screening program enhancement through CFTR multi-mutational analyses. Information on all mutations that have been published since the identification and cloning of the CFTR gene's most common allele, DeltaF508 (or F508del), was reviewed and integrated into a centralized database. The data were then sorted and regional CFTR arrays were determined using mutations that appeared in a given region with a frequency of 0.5% or greater. Final analyses were based on 72,431 CF chromosomes, using data compiled from over 100 original papers, and over 80 regions from around the world, including all nations where CF has been studied using analytical molecular genetics. Initial results confirmed wide mutational heterogeneity throughout the world; however, characterization of the most common mutations across most populations was possible. We also examined CF incidence, DeltaF508 frequency, and regional mutational heterogeneity in a subset of populations. Data for these analyses were filtered for reliability and methodological strength before being incorporated into the final analysis. Statistical assessment of these variables revealed that there is a significant positive correlation between DeltaF508 frequency and the CF incidence levels of regional populations. Regional analyses were also performed to search for trends in the distribution of CFTR mutations across migrant and related populations; this led to clarification of ancestry-genotype patterns that can be used to design CFTR multi-mutation panels for CF screening programs. From comprehensive assessment of these data, we offer recommendations that multiple CFTR alleles should eventually be included to increase the sensitivity of newborn screening programs employing two-tier testing with trypsinogen and DNA analysis.

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109 Mutational Arrays, Detection Rates and Methods by Region* Estimated Projected detection of Number of Number of Country/ allele two CFTR mutations chromosomes Region Mutation array detectiona mutationsb includedc (max/min)d Reference Europe Albania ∆F508 (72.4%) C276X (0.7%) 74.5 55.5 4 270/146 CFGAC [1994]; Macek et al. G85E (0.7%) R1070Q (0.7%) [2002] Austria ∆F508 (62.9%) 457TAT→G (1.2%) 76.6 58.7 11 1516/580 Estiville et al. [1997]; Dörk et al. (total) G542X (3.3%) 2183AA→G (0.7%) [2000]; Macek et al. [2002] CFTRdele2,3 (2.1%) N1303K (0.6%) R1162X (1.9%) I148T (0.5%) R553X (1.7%) R117H (0.5%) G551D (1.2%) Austria ∆F508 (74.6%) 2183AA→G (2.4%) 95.3 90.8 8 126 Stuhrmann et al. [1997] (tyrol) R1162X (8.7%) G551D (1.6%) G542X (2.4%) R347P (1.6%) 2789+5G→A (2.4%) Q39X (1.6%) Belarus ∆F508 (61.2%) R553X (0.5%) 75.2 56.6 9 278/188 Dörk et al. [2000]; Macek et al. G542X (4.5%) R334W (0.5%) [2002] CFTRdele2,3 (3.3%) R347P (0.5%) N1303K (3.2%) S549N (0.5%) W1282X (1.0%) Belgium ∆F508 (75.1%) 622-1A→C (0.5%) 100.0 100.0 27 1504/522 Cuppens et al. [1993]; Mercier et G542X (3.5%) G458V (0.5%) al. [1993]; CFGAC [1994]; N1303K (2.7%) 1898+G→C (0.5%) Estivill et al.[1997] R553X (1.7%) G970R (0.5%) 1717-1G→A (1.6%) 4218insT (0.5%) E60X (1.6%) 394delTT (0.5%) W1282X (1.4%) K830X (0.5%) 2183A→G+2184delA (1.2%) E822K (0.5%) W401X (1.0%) 3272-1G→A (0.5%) A455E (1.0%) S1161R (0.5%) 3272-26A→G (1.0%) R1162X (0.5%) S1251N (1.0%) 3750delAG (0.5%) S1235R (0.8%) S1255P (0.5%) ∆I507 (0.6%) Bulgaria ∆F508 (63.6%) R75Q (1.0%) 93.0 86.5 21 948/432 Angelicheva et al. [1997]; (total) N1303K (5.6%) 2183AA→G (0.9%) Estivill et al. [1997]; Macek G542X (3.9%) G1244V+S912L (0.9%) et al. [2002] R347P (2.2%) G85E (0.9%) 1677delTA (2.1%) 2184insA (0.9%) R1070Q (1.8%) L88X+G1069R (0.8%) Q220X (1.2%) 2789+5G→A (0.8%) 3849+10KbC→T (1.1%) G1244E (0.8%) W1282X (1.0%) 1717-1G→A (0.8%) 2176insC (1.0%) Y919C (0.7%) G1069R (1.0%) WORLDWIDEANALYSISOFCFTRMUTATIONS581 Bulgaria 1) DF508 4) 1677delTA - - 6 13 Angelicheva et al. [1997] (ethnic 2) R347P 5) Q493R Turks) 3) G542X 6) L571S - - 1 30 Angelicheva et al. [1997] Bulgaria 1) DF508 (100.0%) (Gypsy) Croatia ∆F508 (64.5%) G551D (1.1%) 72.5 52.6 5 276 Macek et al. [2002] G542X (3.3%) 3849+10KbC→T (0.7%) N1303K (2.9%) Czech ∆F508 (70.0%) 1898+1G→T (2.0%) 89.6 80.3 10 2196/628 CFGAC [1994]; Estiville et al. Republic CFTRdele2,3 (5.5%) 2143delT (1.2%) [1997]; Dörk et al. [2000]; G551D (3.8%) R347P (0.8%) Macek et al. [2002] N1303K (2.9%) 3849+10KbC→T (0.6%) G542X (2.2%) W1282X (0.6%) Denmark ∆F508 (87.5%) G542X (0.7%) 92.3 85.2 6 1888/678 CFGAC [1994]; Schwartz et al. (excluding 394delTT (1.8%) 621+1G→T (0.6%) [1994]; Estiville et al. [1997] Faroe) N1303K (1.1%) 3659delC (0.6%) Estonia ∆F508 (51.7%) R117C (1.7%) 80.2 64.3 10 165/80 Estivill et al. [1997]; Klaassen et 394delTT (13.3%) E217G (1.7%) al. [1998]; Macek et al. S1235R (3.3%) R1066H (1.7%) [2002] 359insT (1.7%) 3659delC (1.7%) I1005R (1.7%) S1169X (1.7%) Finland ∆F508 (46.2%) G542X (1.9%) 78.8 62.1 4 132/52 CFGAC [1994]; Kere et al. 394delTT (28.8%) 3372delA (1.9%) [1994]; Estivill et al. [1997] France ∆F508 (67.7%) 2789+5G→T (0.79%) 79.7 63.6 12 17854/7420 Chevalier-Porst et al. [1994]; (total) G542X (2.94%) 2184delA+2183A→G (0.77%) Estivill et al. [1997]; Claustres et al. [2000]; Guilloud-Bataille N1303K (1.83%) G551D (0.74%) et al. [2000] 1717-1G→A (1.35%) 1078delT (0.63%) W1282X (0.91%) ∆I507 (0.62%) R553X (0.86%) Y122K (0.59%) France ∆F508 (75.8%) R297Q (0.8%) 98.7 97.4 18 599/365 Férec et al. [1992]; Scotet et al. (Brittany) 1078delT (4.0%) R347H (0.8%) [2000] G551D (3.6%) I1234V (0.8%) N1303K (3.0%) R553X (0.8%) R117H (1.7%) 2789+5G→A (0.8%) 3272-26A→G (1.3%) 4005+1G→A (0.7%) G542X (1.1%) 621+1G→T (0.6%) 1717-1G→A (1.0%) ∆I507 (0.6%) G1249R (0.8%) W846X (0.5%) France ∆F508 (70.0%) N1303K (0.8%) 90.4 81.7 16 250 Claustres et al. [1993] (southern) G542X (6.4%) 3737delA (0.8%) 1717-1G→A (1.6%) R1162X (0.8%) L206W (1.2%) Y1092X (0.8%) R334W (1.2%) S945L (0.8%) ∆I507 (1.2%) K710X (0.8%) 2184delA (1.2%) 1078delT (0.8%) R1158X (1.2%) Y122X (0.8%) (Continued) BOBADILLAETAL. Login to comment
110 Germany ∆F508 (71.8%) 1789+5G→A (0.9%) 87.6 76.7 17 5662/1316 Dörk et al. [1992]; Dörk et al. R553X (2.0%) 3272-26A→G (0.9%) [1994]; Tümmler et al. [1996]; N1303K (1.8%) W1282X (0.7%) Estivill et al. [1997]; Dörk et G542X (1.2%) 2143delT (0.7%) al. [2000] R347P (1.2%) 1078delT (0.6%) CFTRdele2,3 (1.2%) 2183AA→G (0.6%) 3849+10KbC→T (1.0%) 2184insA (0.6%) G551D (0.9% 3659delC (0.6%) 1717-1G→A (0.9%) Greece ∆F508 (52.9%) 3272-26A→G (0.8%) 82.2 67.6 22 2097/718 Kanavakis et al. [1995]; Estivill 621+1G→T (5.0%) R1070Q (0.8%) et al. [1997]; Tzetis et al. G542X (4.1%) W496X (0.7%) [1997]; Macek et al. [2002] N1303K (3.3%) 621+3A→G (0.7%) 2183AA→G (1.8%) ∆I507 (0.7%) 2789+5G→A (1.7%) W1282X (0.7%) E822X (1.6%) 574delA (0.7%) R117H (1.2%) 1677delTA (0.7%) R334W (1.1%) A46D (0.6%) R1158X (1.0%) 3120+1G→A (0.6%) G85E (1.0%) G551D (0.5%) Hungary ∆F508 (54.9%) W1282X (1.8%) 68.3 46.6 9 1133/976 CFGAC [1994]; Estivill et al. 1717-1G→A (1.9%) G542X (1.7%) [1997]; Macek et al. [2002] R553X (2.1%) N1303K (1.3%) Y1092X (1.8%) G551D (1.0%) S1196X (1.8%) Ireland ∆F508 (70.4%) G542X (1.0%) 82.1 67.4 7 801/509 CFGAC [1994]; Estivill et al. G551D (5.7%) 621+1G→T (0.8%) [1994] R117H (2.4%) 1717-1G→A (0.6%) R560T (1.2%) Italy ∆F508 (50.9%) ∆I507 (0.65%) 60.3 36.4 9 3524 Estivill et al. [1997] (total) G542X (3.1%) W1282X (0.62%) 1717-1G→A (1.6%) Y122K (0.59%) N1303K (1.4%) G551D (0.53%) R553X (0.94%) Italy ∆F508 (47.6%) R553X (1.3%) 87.1 75.9 15 225 Bonizzato et al. [1995] (Northeast) R1162X (9.8%) 2789+G→A (1.3%) 2183AA→G (9.3%) Q552X (1.3%) N1303K (4.0%) 621+1G→T (0.9%) G542X (2.7%) W1282X (0.9%) 711+5G→A (2.7%) 3132delTG (0.9%) 1717-1G→A (2.2%) 2790-2A→G (0.9%) G85E (1.3%) TABLE 1. Continued. Estimated Projected detection of Number of Number of Country/ allele two CFTR mutations chromosomes Region Mutation array detectiona mutationsb includedc (max/min)d Reference WORLDWIDEANALYSISOFCFTRMUTATIONS583 Italy ∆F508 (56.4%) 711+1G→T (1.3%) 85.7 73.4 13 660/396 Castaldo et al. [1996]; Castaldo (southern) N1303K (6.8%) G1244E (1.3%) et al. [1999] G542X (5.7%) R1185X (1.3%) W1282X (3.8%) L1065P (1.3%) 1717-1G→A (2.3%) R553X (1.1%) 2183AA→G (1.9%) I148T (0.7%) 4016insT (1.8%) Latvia 1) DF508 (58.3%) 4) CFTRdele2,3 (2.8%) - - 6 36 Dörk et al. [2000]; Macek et al. 2) 3849+10KbC®T (8.3%) 5) W1282X (2.8%) [2002] 3) N1303K (5.6%) 6) 394delTT (2.8%) Lithuania ∆F508 (31.0%) N1303K (2.0%) 39.0 15.2 4 94 Dörk et al. [2000]; Macek et al. R553X (4.0%) CFTRdele2,3 (2.0%) [2002] Macedonia ∆F508 (54.3%) 711+3A→G (1.0%) 69.2 47.9 12 559/226 Petreska et al. [1998]; Dörk et G542X (4.2%) 3849G→A (1.0%) al. [2000]; Macek et al. N1303K (2.0%) 2184insA (0.9%) [2002] CFTRdele2,3 (1.3%) 457TAT→G (0.7%) 621+1G→T (1.3%) V139E (0.7%) 611-1G→T (1.2%) 1811+1G→C (0.6%) Netherlands ∆F508 (74.2%) R1162X (0.9%) 86.8 75.3 9 3167/1442 Gan et al. [1995]; Estiville et al. A455E (4.7%) S1251N (0.9%) [1997]; Collee et al. [1998] G542X (1.8%) N1303K (0.9%) 1717-1G→A (1.5%) W1282X (0.7%) R553X (1.2%) Norway ∆F508 (60.2%) G551D (1.2%) 69.8 48.7 6 410/242 Schwartz et al. [1994]; Estivill 394delTT (4.2%) G542X (0.6%) et al. [1997] R117H (3.0%) N1303K (0.6%) Poland ∆F508 (57.1%) CFTRdele2,3 (1.8%) 73.5 54.0 11 4046/1726 CFGAC [1994]; Estivill et al. 3849+10Kb C→T (2.7%) R560T (1.5%) [1997]; Dörk et al [2000]; G542X (2.6%) W1282X (0.7%) Macek et al. [2002] 1717-1G→A (2.4%) ∆I507 (0.5%) R553X (1.9%) G551D (0.5%) N1303K (1.8%) Portugal ∆F508 (44.7%) R334W (0.7%) 49.7 24.7 5 739/454 CFGAC [1994]; Estivill et al. G542X (1.6%) N1303K (0.7%) [1997] R1066C (2.0%) Romania ∆F508 (36.6%) G542X (1.4%) 51.5 26.5 11 224/74 CFGAC [1994]; Estivill et al. 2043delG (2.0%) R553X (1.4%) [1997]; Popa et al. [1997]; W1282X (1.7%) G576X (1.4%) Macek et al. [2002] 1717-2A→G (1.4%) 1898+1G→A (1.4%) I148T (1.4%) 2183AA→G (1.4%) 621+1G→T (1.4%) Russia ∆F508 (54.4%) 552insA (0.9%) 70.7 50.0 12 5073/2562 CFGAC [1994]; Estivill et al. CFTRdele2,3 (5.0%) G542X (0.9%) [1997]; Dörk et al. [2000]; R553X (3.5%) R334W (0.9%) Macek et al. [2002] 2183AA→G (1.3%) 1677delTA (0.8%) W1282X (1.0%) Y122X (0.5%) 394delTT (1.0%) 1367del5 (0.5%) (Continued) BOBADILLAETAL. Login to comment
112 Jewish 1) 405+1G®A (48.0%) 3) W1282X (17.0%) - - 4 23 Kerem et al. [1995] (Tunisia) 2) DF508 (31.0%) 4) 3849+10KbC®T (4.0%) Jewish 1) G85E 4) G542X - - 6 10 Kerem et al. [1995] (Turkey) 2) DF508 5) 3849+10KbC®T 3) W1282X 6) W1089X Jewish (Yemen) None - - 0 5 Kerem et al. [1995] Lebanon 1) DF508 (35.0%) 6) 4096-28G®A (2.5%) - - 9 40 Desgeorges et al. [1997] 2) W1282X (20.0%) 7) 2789+5G®A (2.5%) 3) 4010del4 (10.0%) 8) M952I (2.5%) 4) N1303K (10.0%) 9) E672del (2.5%) 5) S4X (5.0%) Reunion ∆F508 (52.0%) 1717-1G→A (0.7%) 90.4 81.7 9 138 Cartault et al. [1996] Island Y122X (24.0%) G542X (0.7%) 3120+1G→A (8.0%) A309G (0.7%) A455E (2.2%) 2789+5G→A (0.7%) G551D (1.4%) Saudi North: 3) H139L - - North 1 49 families El-Harith et al. [1997]; Arabia 1) 1548delG 4) L1177X Central 3 Kambouris et al. [1997]; Central: 5) DF508 South 4 Banjar et al. [1999] 1)I1234V 6) 3120+1G®A West 9 2)1548delG 7) 425del42 East 6 3)DF508 8) R553X South: 9) N1303K 1) I1234V East: 2) 1548delG 1) 3120+1G®A 3) 711+1G®T 2) H139L 4) 3120+1G®A 3) 1548delG West: 4) DF508 1) I1234V 5) S549R 2) G115X 6) N1303K Tunisia ∆F508 (17.6%) G85E (2.6%) 58.7 34.5 11 78 Messaoud et al. [1996] G542X (8.9%) W1282X (2.6%) 711+1G→T (7.7%) Y122X (1.3%) N1303K (6.4%) T665S (1.3%) 2766del8NT (6.4%) R47W+D1270N (1.3%) R1066C (2.6%) Turkeye ∆F508 (24.5%) 1066L (1.3%) 80.6 65.0 36 1067/670 Yilmaz et al. [1995]; Estivill et al. 1677delTA (4.1%) E822X (1.3%) [1997]; Onay et al. [1998]; 2789+5G→A (3.9%) 2183+5G→A+2184insA (1.3%) Macek et al. [2002] 2181delA (3.8%) D110H (0.8%) R347H (3.6%) P1013L (0.8%) N1303K (2.9%) 3172delAC (0.8%) 621+1G→T (2.6%) 1259insA (0.8%) G542X (2.6%) M1028I (0.8%) TABLE 1. Continued. Estimated Projected detection of Number of Number of Country/ allele two CFTR mutations chromosomes Region Mutation array detectiona mutationsb includedc (max/min)d Reference WORLDWIDEANALYSISOFCFTRMUTATIONS587 E92K (2.6%) 4005+1G→A (0.7%) A96E (2.6%) W1282X (0.7%) M152V (2.6%) I148T (0.6%) 2183AA→G (2.5%) R1162X (0.6%) 296+9A→T (1.6%) D1152H (0.6%) 2043delG (1.4%) W1098X (0.6%) E92X (1.4%) E831X (0.6%) K68N (1.4%) W496X (0.6%) G85E (1.3%) F1052V (0.5%) R1158X (1.3%) L571S (0.5%) United Arab S549R (61.5%) ∆F508 (26.9%) 88.4 78.1 2 86/52 Frossard et al. [1988]; Emirates Frossard et al. [1999] North/Central/South Americas Argentina ∆F508 (58.6%) N1303K (1.8%) 69.1 47.7 5 326/228 CFGAC [1994]; Chertkoff et al. W1282X (3.9%) 1717-1G→A (0.9%) [1997] G542X (3.9%) Brazilf ∆F508 (47.7%) W1282X (1.3%) 66.8 44.6 10 820/500 CFGAC [1994]; Cabello et al. (total) G542X (7.2%) G85E (1.3%) [1999]; Raskin et al. [1999]; R1162X (2.5%) R553X (0.7%) Bernardino et al. [2000] R334W (2.5%) L206W (0.6%) N1303K (2.4%) 2347delG (0.6%) South East: >∆F508, G542X South: >N1303K Brazil ∆F508 (31.7%) N1303K (2.5%) 42.5 18.1 3 120 Parizotto and Bertuzzo [1997] (Sao Paulo) G542X (8.3%) Canada ∆F508 (59.0%) G542X (0.5%) 98.5 97.0 13 381/200 Rozen et al. [1992]; (Lac St. Jean) 621+1G→T (24.3%) N1303K (0.5%) De Braekeleer et al. [1998] A445E (8.2%) Q890X (0.5%) Y1092X (1.2%) S489X (0.5) 711+1G→T (1.0%) R117C (0.5%) I148T (1.0%) R1158 (0.5%) G85E (0.8%) Canada ∆F508 (71.4%) ∆I507 (1.3%) 90.9 82.6 7 77 Rozen et al. [1992] (Quebec City) 711+1G→T (9.1%) Y1092X (1.3%) 621+1G→T (5.2%) N1303K (1.3%) A455E (1.3%) Canada ∆F508 (70.9%) W1282X (0.9%) 82.0 67.2 10 632 Kristidis et al. [1992] (Toronto) G551D (3.1%) R117H (0.9%) G542X (2.2%) 1717-1G→A (0.6%) 621+1G→T (1.3%) R560T (0.6%) N1303K (0.9%) ∆I507 (0.6%) Chile ∆F508 (29.2%) R553X (4.2%) 33.4 11.2 2 72 Rios et al. [1994] Columbia 1) DF508 (35.4%) 3) N1303K (2.1%) - - 4 48 Restrepo et al. [2000] 2) G542X (6.3%) 4) W1282X (2.1%) Ecuador 1) DF508 (25%) - - 1 20 Paz-y-Mino et al. [1999] (Continued) BOBADILLAETAL. Login to comment
113 Mexico ∆F508 (41.6%) G551S (0.5%) 75.5 57.0 35 374/194 Orozco et al.[1993]; Villalobos- G542X (5.6%) 1078delT (0.5%) Torres et al. [1997]; Liang et al. ∆I507 (2.5%) Y1092X (0.5%) [1998]; Orozco et al. [2000] S549N (1.9%) R117H (0.5%) N1303K (1.7%) G85E (0.5%) R75X (1.5%) 1716G→A (0.5%) 406-1G→A (1.5%) W1204X (0.5%) I148T (1.5%) W1098C (0.5%) 3849+10KbC→T (1.5%) 846delT (0.5%) 621+1G→T (1.2%) P750L (0.5%) 2055del9→A (1.0%) V754M (0.5%) 935delA (1.0%) R75Q (0.5%) I506T (1.0) W1096X (0.5%) 3199del6 (1.0%) L558S (0.5%) 2183AA→G (1.0%) 4160insGGGG (0.5%) G551D (0.5%) 297-1G→A (0.5%) R553X (0.5%) H199Y (0.5%) 1924del7 (0.5%) United States ∆F508 (68.6%) R553X (0.9%) 79.7 63.5 10 25048 Cystic Fibrosis Foundation (total) G542X (2.4%) 621+1G→T (0.9%) [1998] G551D (2.1%) 1717-1G→A (0.7%) W1282X (1.4%) 3849+10KbC→T (0.7%) N1303K (1.3%) R117H (0.7%) United States ∆F508 (48.0%) S1255X (1.4%) 77.3 59.8 16 160/148 Carles et al. [1996]; Macek et al. (African 3120+1G→A (12.2%) 444delA (0.7%) [1997]; Dörk et al. [1998]; American) 2307insA (2.0%) R334W (0.7%) Friedman et al. [1998] A559T (2.0%) ∆I507 (0.7%) R553X (2.0%) 1717-1G→A (0.7%) ∆F311 (2.0%) G542X (0.7%) G480C (1.4%) S549N (0.7%) 405+3A→C (1.4%) G551D (0.7%) United States 1) L1093P - - 1 2 Yee et al. [2000] (Cherokee) United States Non-French: French: Non- Non- Non- Non- Bayleran et al. [1996] (Maine) ∆F508 (82.0%) ∆F508 (58%) French: French: French: French: G542X (2.6%) 711+1G→T (8.3%) 95.3 90.8 11 191 G551D (2.6%) I148T (4.2%) French: French: French: French: N1303K (2.1%) A455E (4.2%) 80.3 64.5 8 72 R560T (1.0%) 1717-1G→A (1.4%) Total: 621+1G→T (1.0%) G85E (1.4%) 263 711+1G→T (1.0%) 621+1G→T (1.4%) R117H (1.0%) Y1092X (1.4%) 1717-1G→A (1.0%) G85E (0.5%) W1282X (0.5%) TABLE 1. Continued. Estimated Projected detection of Number of Number of Country/ allele two CFTR mutations chromosomes Region Mutation array detectiona mutationsb includedc (max/min)d Reference WORLDWIDEANALYSISOFCFTRMUTATIONS589 United States ∆F508 (46.0%) R334W (1.6%) 58.5 34.2 7 129 Grebe et al. [1994] (SW Hispanic) G542X (5.4%) W1282X (0.8%) 3849+10KbC→T (2.3%) R553X (0.8%) R1162X (1.6%) United States 1) R1162X - - 3 17 Mercier et al. [1992] (SW Native 2) D648V American) 3) G542X United States 1) R1162X 3) G542X - - 4 16 Mercier et al. [1994] (Zuni Pueblo) 2) 3849+10KbC®T 4) D648V Venezuela ∆F508 (29.6%) G542X (3.7%) 33.3 11.1 2 54 Restrepo et al. [2000] Other Regions Australia ∆F508 (76.9%) 621+1G→T (1.1%) 88.7 78.7 8 761/464 CFGAC [1994] G551D (4.5%) N1303K (0.9%) G542X (2.8%) W1282X (0.6%) R553X (1.3%) R117H (0.6%) East Asia 1) 1898+1G®T 2) 1898+5G®T - - 2 28 Suwanjutha et al. [1998] Hutterite 1) M1101K (69.0%) 2) DF508 (31.0%) - - 2 32 Zielenski et al. [1993] Brethren New Zealand ∆F508 (78.0%) N1303K (1.9%) 87.4 76.4 5 636 CFGAC [1994] G551D (4.4%) 621+1G→T (1.1%) G542X (2.0%) *This table presents the mutation panels for all regions investigated in this study. Login to comment
213 Ideal Recommended CFTR Mutation Screening Panel for 2001 Neonatal Screening in the USA* Location Estimated Mutation in CFTRa percentageb Reason for inclusion DF508 Exon 10 68.6% CFF registry, >1%, Pan-European G542X Exon 11 2.4% CFF registry, >1%, Mediterranean G551D Exon 11 2.1% CFF registry, >1%, Celtic W1282X Exon 20 1.4% CFF registry, >1%, Ashkenazi Jew N1303K Exon 21 1.3% CFF registry, >1%, Mediterranean R553X Exon 11 0.9% CFF registry, >0.5%, Hispanic 621+1G®T Intron 4 0.9% CFF registry, >0.5%, multi-ethnic 1717-1G®A Intron 10 0.7% CFF registry, >0.5%, Italian 3849+10KbC®T Intron 19 0.7% CFF registry, >0.5%, Hispanic R117Hc Exon 4 0.7% CFF registry, >0.5% 1898+1G→T Intron 12 0.4% CFF registry, >0.1%, East Asian DI507 Exon 10 0.3% CFF registry, >0.1%, Hispanic 2789+5G®A Intron 14b 0.3% CFF registry, >0.1% G85E Exon 3 0.3% CFF registry, >0.1% R347P Exon 7 0.2% CFF registry, >0.1% R334W Exon 7 0.2% CFF registry, >0.1%, multi-ethnic R1162X Exon 19 0.2% CFF registry, >0.1%, multi-ethnic R560T Exon 11 0.2% CFF registry, >0.1% 3659delC Exon 19 0.2% CFF registry, >0.1% A455E Exon 9 0.2% CFF registry, >0.1% 2184delA Exon 13 0.1% CFF registry, >0.1% S549N Exon 11 0.1% CFF registry, >0.1%, multi-ethnic 711+1G®T Intron 5 0.1% CFF registry, >0.1% R75X Exon 3 0.2% Hispanic 406-1G→A Intron 3 0.2% Hispanic I148T Exon 4 0.2% Hispanic, French 2055del9→A Exon 13 0.1% Hispanic 935delA Exon 6b 0.1% Hispanic I506T Exon 10 0.1% Hispanic 3199del6 Exon 17a 0.1% Hispanic 2183AA→G Exon 13 0.1% Hispanic 3120+1G®A Intron 16 1.5% African American, Arabian 2307insA Exon 13 0.2% African American A559T Exon 11 0.2% African American ∆F311 Exon 7 0.2% African American G480C Exon 10 0.2% African American 405+3A→C Intron 3 0.2% African American S1255X Exon 20 0.2% African American L1093P Exon 17b Undetermined Native American D648V Exon 13 Undetermined Native American I1234V Exon 19 Undetermined Arabian linkage S549R Exon 11 Undetermined Arabian linkage 1898+5G→T Intron 12 Undetermined East Asian linkage CFTRdele2,3 Exons 2,3 Undetermined Eastern European linkage (Slavic) Y1092X Exon 17b Undetermined French linkage 394delTT Exon 3 Undetermined Nordic linkage Y569D Exon 12 Undetermined Pakistani linkage 3905insT Exon 20 Undetermined Swiss linkage (also: Amish, Acadian, Mennonite) 1898+1G®A Intron 12 Undetermined Welsh linkage M1101k Exon 17b Undetermined Hutterite ancestry *This table presents the top 50 mutations in the USA based on the Cystic Fibrosis Foundation CF Registry data from 1997 [Cystic Fibrosis Foundation, 1998], and data generated during our investigation. Login to comment

[hide] Negative sweat test in hypertrypsinaemic infants w... Eur J Pediatr. 2002 Apr;161(4):212-5. Padoan R, Bassotti A, Seia M, Corbetta C
Negative sweat test in hypertrypsinaemic infants with cystic fibrosis carrying rare CFTR mutations.
Eur J Pediatr. 2002 Apr;161(4):212-5., [PMID:12014388]

Abstract [show]
Persistent hypertrypsinaemia in newborn screening for cystic fibrosis (CF) recognises subjects at high risk to be affected. Diagnosis is confirmed by a positive sweat test and/or by the presence of two mutations in the cystic fibrosis transmembrane regulator gene. The aim of the present study was to evaluate the occurrence of a negative sweat test (chloride < 60 mmol/l) during the first months of life, in hypertrypsinaemic infants, which would lead to a delayed diagnosis. We reviewed clinical charts of CF patients born between January 1993 and September 1998, when the neonatal screening programme consisted of an immunoreactive trypsinogen (IRT)/DNA (F508del) + IRT strategy. Laboratory and clinical data were collected for patients diagnosed after 12 months of life. Out of 446,492 newborns, 104 CF patients were diagnosed giving an overall incidence of 1:4293. Of these, six had a blood IRT level above the cut off value (99th percentile) and a negative sweat test in the first trimester of life. At a mean age of 3.5years, the patients were again referred to our CF Centre for re-evaluation in order to confirm or exclude the disorder. Molecular analysis identified the following genotypes: F508del/A309D, F508del/3849 + 10kbC-->T, F508del/R117H (in two patients), R117H/ L997F, and F508del/R117L. CONCLUSION: Infants with cystic fibrosis bearing a spectrum of mild cystic fibrosis transmembrane regulator gene mutations may present as hypertrypsinaemic newborns with a sweat chloride within the normal range. Reference values for normal sweat test during the first months of life should be revised. A wide molecular genetic analysis is recommended for newborns presenting persistent hypertrypsinaemia and a sweat test result > 30 mmol/l in order to diagnose atypical forms of the disease.

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14 Diagnostic delay has been reported for patients bearing specific CFTR gene mutations such as R117H, D1152H, 3849+10kbCfiT, A455E and 2789+5GfiA, which were associated with a non-pathological sweat chloride level [3, 6, 9,13]. Login to comment

[hide] Development and evaluation of a PCR-based, line pr... Clin Chem. 2002 Jul;48(7):1121-3. Wang X, Myers A, Saiki RK, Cutting GR
Development and evaluation of a PCR-based, line probe assay for the detection of 58 alleles in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.
Clin Chem. 2002 Jul;48(7):1121-3., [PMID:12089190]

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68 Amplicon Size, bp Mutations (polymorphisms) Exon 13 598 2307 insA Intron 8, exon 09 548 A455E, 5T (7/9 T polymorphism) Exon 10 482 G480C, ⌬I507, ⌬F508 (F508C, I507V, I506V polymorphisms) Intron 10, exon 11 433 1717-1G3A, G542X, G551D, R553X, A559T, R560T Exon 19 420 R1162X, 3659delC Exon 21 397 N1303K Exon 20 359 S1255X, W1282X Exon 07 328 1078delT, R334W, R347P Exon 04, intron 4 288 R117H, 621ϩ1G3T Intron 14b 248 2789ϩ5G3A Intron 19 237 3849ϩ10kbC3T Exon 03 210 G85E, 405ϩ3A3C Intron 5 166 711ϩ1G3T Intron 16 139 3120ϩ1G3A Clinical Chemistry 48, No. Login to comment
80 The signal intensities of the wild-type alleles for A455E, G480C, I507/F508, and 2307insA probes were decreased when 12.5 ng of DNA was used, but could still be distinguished from background even at 6.25 ng of DNA. Login to comment
88 The genotypes of each sample are as follows: lane 1, ϩ/ϩ (ϩ is the wild type); lane 2, 5T, R117H/3659delC; lane 3, G542X/ϩ; lane 4, I506V/ϩ; lane 5, I507V/ϩ; lane 6, F508C/⌬F508; lane 7, G85E/⌬F508; lane 8, 405ϩ3A3C/3120ϩ1G3C; lane 9, R117H/ϩ; lane 10, 621ϩ1G3T/⌬F508; lane 11, 711ϩ1G3T/⌬F508; lane 12, 1078delT/ϩ; lane 13, R334W/⌬F508; lane 14, R347P/⌬F508; lane 15, A455E/ϩ; lane 16, G480C/⌬F508; lane 17, ⌬I507/ϩ; lane 18, ⌬F508/ϩ; lane 19, 1717-1G3A/ϩ; lane 20, G542X/ϩ; lane 21, G551D/⌬F508; lane 22, R553X/ϩ; lane 23, R560T/⌬F508; lane 24, G551D/A559T; lane 25, 2307insA/ϩ; lane 26, 2789ϩ5G3A/⌬F508; lane 27, 3120ϩ1G3A/⌬F508; lane 28, R1162X/R1162X; lane 29, 3659delC/⌬F508; lane 30, 3849ϩ10kbC3T/⌬F508; lane 31, S1255X/⌬F508; lane 32, W1282X/G542X; lane 33, N1303K/ϩ. Login to comment

[hide] Predicting the risk of cystic fibrosis with abnorm... Am J Med Genet. 2002 Jun 15;110(2):109-15. Muller F, Simon-Bouy B, Girodon E, Monnier N, Malinge MC, Serre JL
Predicting the risk of cystic fibrosis with abnormal ultrasound signs of fetal bowel: results of a French molecular collaborative study based on 641 prospective cases.
Am J Med Genet. 2002 Jun 15;110(2):109-15., 2002-06-15 [PMID:12116247]

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Hyperechogenic fetal bowel is prenatally detected by ultrasound during the second trimester of pregnancy in 0.1-1.8% of fetuses. It has been described as a normal variant but has often been associated with severe diseases, notably cystic fibrosis (CF). The aim of our study was to determine the risk of CF in a prospective study of 641 fetuses with ultrasonographically abnormal fetal bowel and the residual risk when only one mutation is detected in the fetus. Fetal cells and/or parental blood cells were screened for CFTR mutations. Two screening steps were used, the first covering the mutations most frequently observed in French CF patients (mutation detection rate of 70-90%) and, when a CF mutation was detected, a DGGE-sequencing strategy. We observed a 3.1% risk of CF when a digestive tract anomaly was prenatally observed at routine ultrasound examination. The risk was higher when hyperechogenicity was associated with bowel dilatation (5/29; 17%) or with the absence of gall bladder (2/8; 25%). The residual risk of CF was 11% when only one CF mutation was detected by the first screening step, thereby justifying in-depth screening. Mutations associated with severe CF (DeltaF508 mutation) were more frequently observed in these ultrasonographically and prenatally detected CF cases. However, the frequency of heterozygous cases was that observed in the normal population, which demonstrates that heterozygous carriers of CF mutations are not at increased risk for hyperechogenic bowel. In conclusion, fetal bowel anomalies indicate a risk of severe cystic fibrosis and justify careful CFTR molecular analysis.

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52 T, 1078delT, R347P, R347H, R334W, A455E, 1898 þ 1G ! Login to comment

[hide] Genotype-phenotype correlation in cystic fibrosis:... Am J Med Genet. 2002 Jul 22;111(1):88-95. Salvatore F, Scudiero O, Castaldo G
Genotype-phenotype correlation in cystic fibrosis: the role of modifier genes.
Am J Med Genet. 2002 Jul 22;111(1):88-95., 2002-07-22 [PMID:12124743]

Abstract [show]
More than 1,000 mutations have been identified in the cystic fibrosis (CF) transmembrane regulator (CFTR) disease gene. The impact of these mutations on the protein and the wide spectrum of CF phenotypes prompted a series of Genotype-Phenotype correlation studies. The CFTR genotype is invariably correlated with pancreatic status-in about 85% of cases with pancreatic insufficiency and in about 15% of cases with pancreatic sufficiency. The correlations between the CFTR genotype and pulmonary, liver, and gastrointestinal expression are debatable. The heterogeneous phenotype in CF patients bearing the same genotype or homozygotes for nonsense mutations implicated environmental and/or genetic factors in the disease. However, the discordant phenotype observed in CF siblings argued against a major role of environmental factors and suggested that genes other than CFTR modulate the CF phenotype. A locus that modulates gastrointestinal expression was identified in mice and subsequently in humans. By analyzing nine CF patients discordant for meconium ileus we were able to show that this locus had a dominant effect. Moreover, in a collaborative study we found a higher rate of polymorphisms in beta-defensin genes 1 and 2 in CF patients and in controls. In another multicenter study mutations in alpha-1 antitrypsin (A1AT) and mannose binding lectin genes were found to be independent risk factors for liver disease in CF patients. The body of evidence available suggests that the variegated CF phenotype results from complex interactions between numerous gene products.

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46 A series of mutations usually associated with pancreatic sufficiency have been identified and defined as ''mild`` with reference to pancreatic status [Kerem et al., 1989c]: G85E, G91R, R117H, E193K, P205S, R334W, T338I, R347H, R347L, R347P, R352Q, A455E, S492F, S549N, P574H, D579G, 711 þ 5 G > A, C866Y, F1052V, H1054D, R1066H, R1068H, H1085R, D1152H, S1159P, S1251N, F1286S, G1349D, 2789 þ 5 G > A, and 3849 þ 10kb C > T [Dean et al., 1990; Cutting et al., 1990a; Cremonesi et al., 1992; Highsmith et al., 1994]. Login to comment
59 Several findings suggest that the pulmonary phenotype is directly related to the CFTR genotype: 1) missense mutations (e.g., R117H and A455E) give rise to a milder pulmonary expression [Gan et al., 1995; De Braekeleer et al., 1997]; 2) CF patient homozygotes for DF508 and compound heterozygotes for DF508 and a nonsense mutation at the level of the nucleotide binding folder (NBF) encoding region of the CFTR gene are more susceptible to P. aeruginosa infections [Kubesch et al., 1993; Davidson et al., 1995]; and 3) CF patient homozygotes for DF508 invariably have a severe pulmonary phenotype [Johansen et al., 1991]. Login to comment

[hide] Screening for cystic fibrosis in newborn infants: ... J Med Screen. 2002;9(2):60-3. Corbetta C, Seia M, Bassotti A, Ambrosioni A, Giunta A, Padoan R
Screening for cystic fibrosis in newborn infants: results of a pilot programme based on a two tier protocol (IRT/DNA/IRT) in the Italian population.
J Med Screen. 2002;9(2):60-3., [PMID:12133923]

Abstract [show]
OBJECTIVE: To assess the performance of a two tier neonatal screening programme (IRT/DNA/IRT) for cystic fibrosis, based on immunoreactive trypsinogen (IRT) followed by direct cystic fibrosis transmembrane conductance regulator (CFTR) gene analysis (based on a panel of up to 31 mutations) in hypertrypsinaemic newborn infants and to compare it with a previous screening protocol. SETTING: The study comprised all the newborn infants in the period 1 October 1998 to 31 December 1999 in the Lombardia region, north western Italy. METHODS: The screening strategy consisted of an immunoreactive trypsinogen assay from dried blood spots, a polymerase chain reaction (PCR) followed by an oligonucleotide ligation assay (PCR-OLA), and a sequence code separation. RESULTS: 104 609 newborn infants were screened. 1457 hypertrypsinaemic infants (1.39%) were analysed with the PCR-OLA assay. 18 newborn homozygotes or compound heterozygotes for CFTR mutations were identified and referred to the cystic fibrosis (CF) centre at a mean age of 3 weeks. 125 infants presenting only one mutation were recalled for a sweat test: a diagnosis of CF was made in 13 infants, and parents of 112 neonates identified as carriers (1:13) received genetic counselling. The remaining 1314 hypertrypsinaemic newborn infants were recalled for IRT retesting and 177 were referred for a sweat test because the second IRT measurement was above the cut off value. Among this group a further two infants were diagnosed with CF (1.1%) leading to a CF prevalence of 1:3170. CONCLUSIONS: This strategy resulted in an early and accurate diagnosis of CF. The IRT/DNA/IRT protocol with an OLA assay was shown to be useful in an Italian population with a genetic heterogeneity, leading to the identification of 94% of infants with CF.

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266 Mutations identified by the assay are G85E, 621+1G→T, R117H, Y122X, 711+1G→T, 1078delT, R347P, R347H, R334W, A455E, 1898+1G→A, 2183-AA→G, 2789+5G→A, delF508, I507del, Q493X, V520F, 1717-1G→A, G542X, G551D, R553X, R560T, S549R, S549N, 3849+10kbC→T, 3849+4A→G, R1162X, 3659delC, W1282X, 3905insT, and N1303K. Login to comment

[hide] Analysis by mass spectrometry of 100 cystic fibros... Hum Reprod. 2002 Aug;17(8):2066-72. Wang Z, Milunsky J, Yamin M, Maher T, Oates R, Milunsky A
Analysis by mass spectrometry of 100 cystic fibrosis gene mutations in 92 patients with congenital bilateral absence of the vas deferens.
Hum Reprod. 2002 Aug;17(8):2066-72., [PMID:12151438]

Abstract [show]
BACKGROUND: Limited mutation analysis for congenital bilateral absence of the vas deferens (CBAVD) has revealed only a minority of men in whom two distinct mutations were detected. We aimed to determine whether a more extensive mutation analysis would be of benefit in genetic counselling and prenatal diagnosis. METHODS: We studied a cohort of 92 men with CBAVD using mass spectrometry and primer oligonucleotide base extension to analyse an approximately hierarchical set of the most common 100 CF mutations. RESULTS: Analysis of 100 CF mutations identified 33/92 (35.9%) patients with two mutations and 29/92 (31.5%) with one mutation, compound heterozygosity accounting for 94% (31/33) of those with two mutations. This panel detected 12.0% more CBAVD men with at least one mutation and identified a second mutation in >50% of those considered to be heterozygotes under the two routine 25 mutation panel analyses. CONCLUSION: Compound heterozygosity of severe/mild mutations accounted for the vast majority of the CBAVD patients with two mutations, and underscores the value of a more extensive CF mutation panel for men with CBAVD. The CF100 panel enables higher carrier detection rates especially for men with CBAVD, their partners, partners of known CF carriers, and those with 'mild' CF with rarer mutations.

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20 Given the frequency of CF mutations, especially in the Caucasian population ( in 25), and the common request by CBAVD men to sire their own offspring by using surgical Table I. The 100 most common cystic fibrosis mutations listed by exon Mutationa Exonb Frequency (%)c G85E 3 0.1 394delTT 3 Swedish E60X 3 Belgium R75X 3 405ϩ1G→A Int 3 R117H 4 0.30 Y122X 4 French 457TAT→G 4 Austria I148T 4 Canada (French Canadian) 574delA 4 444delA 4 R117L 4 621ϩ1G→T Int 4 0.72 711ϩ1G→T Int 5 Ͼ0.1 712-1G→T Int 5 711ϩ5G→A Int 5 Italy (Caucasian) L206W 6a R347P 7 0.24 1078delT 7 Ͼ0.1 R334W 7 Ͼ0.1 1154InsTC 7 T338I 7 Italy R347H 7 Turkey Q359K/T360K 7 Israel (Georgian Jews) I336K 7 R352Q 7 G330X 7 S364P 7 A455E 9 0.20 I507 10 0.21 F508 10 66.02 1609delCA 10 Spain (Caucasian) V520F 10 Q493X 10 C524X 10 G480C 10 Q493R 10 1717-1G→A Int 10 0.58 R553X 11 0.73 G551D 11 1.64 G542X 11 2.42 R560T 11 Ͼ0.1 S549N 11 Q552X 11 Italy S549I 11 Israel (Arabs) A559T 11 African American R553G 11 R560K 11 1812-1G→A Int 11 A561E 12 E585X 12 Y563D 12 Y563N 12 1898ϩ1G→A Int 12 0.22 1898ϩ1G→C Int 12 2183AA→G 13 Italian 2184delA 13 Ͻ0.1 K710X 13 2143delT 13 Moscow (Russian) 2184InsA 13 1949del84 13 Spain (Spanish) 2176InsC 13 2043delG 13 2307insA 13 2789ϩ5G→A Int 14b Ͼ0.1 2869insG 15 S945L 15 Q890X 15 3120G→A 16 2067 Table I. continued Mutationa Exonb Frequency (%)c 3120ϩ1G→A Int 16 African American 3272-26A→G Int 17a R1066C 17b Portugal (Portugese) L1077P 17b R1070Q 17b Bulgarian W1089X 17b M1101K 17b Canada (Hutterite) R1070P 17b R1162X 19 0.29 3659delC 19 Ͼ0.1 3849G→A 19 3662delA 19 3791delC 19 3821delT 19 Russian Q1238X 19 S1235R 19 France, South S1196X 19 K1177R 19 3849ϩ10kbC→T Int 19 0.24 3849ϩ4A→G Int 19 W1282X 20 1.22 S1251N 20 Dutch, Belgian 3905insT 20 Swiss, Acadian, Amish G1244E 20 R1283M 20 Welsh W1282R 20 D1270N 20 S1255X 20 African American 4005ϩ1G→A Int 20 N1303K 21 1.34 W1316X 21 aMutations were chosen according to their frequencies (Cystic Fibrosis Genetic Analysis Consortium, 1994; Zielenski and Tsui, 1995; Estivill et al., 1997). Login to comment
35 ACMG 25 mutation panel (ACMG25): The following mutations are the recommended core mutations for general population CF carrier screening by American College of Medical Genetics (ACMG) (Grody, et al 2001): ∆F508, G542X, N1303K, G551D, W1282X, 1717-1G→A, R553X, 621ϩ1G→T, R1162X, R117H, ∆I507, 1898ϩ1G→A, G85E, R347P, A455E, R560T, R334W, 3849ϩ10kbC→T, 3659delC, 1078delT, 2789ϩ5G→A, 711ϩ1G→T, 2184delA, 3120ϩ1G→A and I148T. Login to comment
86 CFTR mutations in 92 men with congenital bilateral absence of vas deferens Mutations CFTR mutation panels CF25 CF25 ϩ 5T ACMG25 ACMG25 ϩ 5T CF100 Mutations detected in ∆F508 39 39 39 39 39 CF25 mutation panel R117H 4 4 4 4 4 W1282X 4 4 4 4 4 G551D 3 3 3 3 3 G542X 1 1 1 1 1 N1303K 1 1 1 1 1 IVS8-polyT IVS8-5T 33 33 33 Additional mutations L206W 3 detected not in CF25 D1270N 2 mutation panel 1154InsTC 1 3272-26A→G 1 A455E 1 1 1 R334W 1 1 1 Q890X 1 Total 14 52 85 54 87 95 respectively, in the total number of patients with at least one mutation. Login to comment
91 CFTR genotypes in 92 men with congenital bilateral absence of vas deferens Genotypesa CFTR mutation panelsb CF25 CF25 ϩ 5T ACMG25 ACMG25 ϩ 5T CF100 Two mutations ∆F508/5T 16 16 16 W1282X/5T 4 4 4 ∆F508/R117Hc 3 3 3 3 3 G542X/5T 1 1 1 G551D/5T 1 1 1 ∆F508/L206W 2 ∆F508/A455E 1 1 1 ∆F508/3272-26A→G 1 Q890X/5T 1 L206W/5T 1 D1270N/D1270N 1 5T/5T 1 1 1 Sub-total 3 26 4 27 33 One mutation ∆F508/ϩ 36 20 35 19 16 5T/ϩ 9 9 7 G551D/ϩ 3 2 3 2 2 G542X/ϩ 1 1 R117H/ϩ 1 1 1 1 1 N1303K/ϩ 1 1 1 1 1 W1282X/ϩ 4 4 R334W/ϩ 1 1 1 1154InsTC/ϩ 1 Sub-total 46 33 46 33 29 Total (%) 49 (53.3) 59 (64.1) 50 (54.3) 60 (65.2) 62 (67.4) No mutation (%) 43 (46.7) 33 (35.9) 42 (45.7) 32 (34.8) 30 (32.6) aMutations L206W, 3272-26A→G, Q890X, D1270N, 1154InsTC and 5T are not in either CF25 and ACMG25 panels, while A455E and R334W are not in CF25, but are part of ACMG25 panel. Login to comment

[hide] New therapeutic approaches for cystic fibrosis lun... J R Soc Med. 2002;95 Suppl 41:58-67. Davies JC
New therapeutic approaches for cystic fibrosis lung disease.
J R Soc Med. 2002;95 Suppl 41:58-67., [PMID:12216276]

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70 Also, certain mutations such as A455E, associated with approximately 5% CFTR function, appear to confer a mild pulmonary phenotype27. Login to comment

[hide] Demographics of the UK cystic fibrosis population:... Eur J Hum Genet. 2002 Oct;10(10):583-90. McCormick J, Green MW, Mehta G, Culross F, Mehta A
Demographics of the UK cystic fibrosis population: implications for neonatal screening.
Eur J Hum Genet. 2002 Oct;10(10):583-90., [PMID:12357328]

Abstract [show]
The objective was to determine the composition of the Cystic Fibrosis (CF) Population attending specialist UK CF centres in terms of age, gender, age at diagnosis, genotype and ethnicity. With the planned introduction of the national CF screening programme in the UK, cystic fibrosis transmembrane regulator (CFTR) mutations were compared between different ethnic groups enabling a UK-specific frequency of mutations to be defined. Data were analysed from the patient biographies held in the UK CF Database (see www.cystic-fibrosis.org.uk). The currently registered population of 5,274 CF patients is 96.3% Caucasian with a male preponderance that significantly increases with age. The majority of the 196 non-Caucasian CF patients are from the Indian Subcontinent (ISC), of which one in 84 UK CF patients are of Pakistani origin. The commonest CFTR mutation, deltaF508, is found in 74.1% of all CF chromosomes. In the Caucasian CF population, 57.5% are deltaF508 homozygotes but the UK ISC CF population with only 24.7%, has significantly fewer deltaF508 homozygotes patients (95% confidence interval (CI) 0.2-0.4). The distribution of Caucasian patients with deltaF508/deltaF508, deltaF508/Other and Other/Other does not fit the expected distribution with a Hardy-Weinberg model unless those patients without a detected mutation are excluded (P<0.001). The UK CF Database has shown the UK CF population to have distinct characteristics separate from the North American and European CF Registries. The ISC group contains many mutations not recognised by current genetic analysis, and one in four ISC patients have no CFTR mutations identified. The CFTR analysis proposed for the screening programme would detect 96% of patients registered in the database, but is unlikely to achieve the desired >80% detection rates in the ethnic minority groups. Screen-positive, non-Caucasian infants without an identifiable CFTR mutation should be referred for a sweat test and genetic counselling when serum trypsinogen concentrations remain elevated after birth.

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83 The additional eleven are S549N, 3849+4A?G, 3905insT, 2789+5G?A, Y122X, 711+1G?T, R347P, R347H, R334W, A455E and 3281AA?G. Login to comment

[hide] Standards and guidelines for CFTR mutation testing... Genet Med. 2002 Sep-Oct;4(5):379-91. Richards CS, Bradley LA, Amos J, Allitto B, Grody WW, Maddalena A, McGinnis MJ, Prior TW, Popovich BW, Watson MS, Palomaki GE
Standards and guidelines for CFTR mutation testing.
Genet Med. 2002 Sep-Oct;4(5):379-91., [PMID:12394352]

Abstract [show]
One mission of the ACMG Laboratory Quality Assurance (QA) Committee is to develop standards and guidelines for clinical genetics laboratories, including cytogenetics, biochemical, and molecular genetics specialties. This document was developed under the auspices of the Molecular Subcommittee of the Laboratory QA Committee by the Cystic Fibrosis (CF) Working Group. It was placed on the "fast track" to address the preanalytical, analytical, and postanalytical quality assurance practices of laboratories currently providing testing for CF. Due to the anticipated impact of the ACMG recommendation statement endorsing carrier testing of reproductive couples, it was viewed that CF testing would increase in volume and that the number of laboratories offering CF testing would also likely increase. Therefore, this document was drafted with the premise of providing useful information gained by experienced laboratory directors who have provided such testing for many years. In many instances, "tips" are given. However, these guidelines are not to be interpreted as restrictive or the only approach but to provide a helpful guide. Certainly, appropriately trained and credentialed laboratory directors have flexibility to utilize various testing platforms and design testing strategies with considerable latitude. We felt that it was essential to include technique-specific guidelines of several current technologies commonly used in laboratories providing CF testing, since three of the four technologies discussed are available commercially and are widely utilized. We take the view that these technologies will change, and thus this document will change with future review.

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60 Examples of such mutations include R117H, 3849 ϩ 10 kbCϾT, A455E, 2789 ϩ 5GϾA, G85E, and R334W. Login to comment
307 ⌬F508 R553X R1162X 2184delA 3120ϩ1GϾA ⌬I507 G542X G551D W1282X N1303K 621ϩ1GϾT R117H 1717-1GϾA A455E R560T G85E R334W R347P 711ϩ1GϾT 1898ϩ1GϾA 1078delT 3849ϩ10kbCϾT 2789ϩ5GϾA 3659delC I148T CF 3.3.2 Inclusion of the common R117H mutation in the test panel screens for CBAVD as well as for CF: The phenotypic consequences of the R117H mutation are modulated in cis by the 5/7/9T polypyrimidine tract in intron 8 such that R117H/7T is associated with CBAVD and R117H/5T is associated with CF.34 Moreover, the 5T allele is associated as a trans mutation in CBAVD.35 It is recommended that the 5/7/9T variant be excluded from the routine carrier screen but tested as a reflex for carriers shown to be heterozygous for the R117H mutation. Login to comment

[hide] Airways in cystic fibrosis are acidified: detectio... Thorax. 2002 Nov;57(11):926-9. Tate S, MacGregor G, Davis M, Innes JA, Greening AP
Airways in cystic fibrosis are acidified: detection by exhaled breath condensate.
Thorax. 2002 Nov;57(11):926-9., [PMID:12403872]

Abstract [show]
BACKGROUND: The loss of cystic fibrosis transmembrane conductance regulator (CFTR) mediated chloride conductance does not fully explain the diverse pathologies evident in patients with cystic fibrosis (CF). Bicarbonate (HCO(3)(-)) secretion is also impaired in CFTR expressing tissues and CFTR is thought to regulate HCO(3)(-) secretion at the apical membrane of epithelial cells. We hypothesised that the epithelial lining fluid (ELF) of patients with CF would be acidified and that this may be worsened during an infective exacerbation due to the increased inflammatory burden. METHODS: pH and nitrite levels in exhaled breath condensate (EBC) from 12 healthy non-smoking controls and 30 patients with CF (11 of whom were in an infective exacerbation) were measured. A further nine patients were studied before and after intravenous antibiotic treatment for an exacerbation of CF. RESULTS: The pH of EBC was significantly lower in patients with stable CF than in controls (5.88 (0.32) v 6.15 (0.16), p=0.017), and was further reduced in CF patients with an exacerbation (5.32 (0.38), p=0.001) compared with stable CF patients. EBC pH increased significantly following antibiotic treatment from 5.27 (0.42) to 5.71 (0.42), p=0.049). Nitrite levels in EBC were increased in CF patients with an exacerbation compared with control subjects (4.4 (4.0) micro m v 1.6 (1.6) micro m p=0.047). No correlation was found between EBC pH and nitrite levels. CONCLUSIONS: These findings support the hypothesis that airway acidification occurs in CF. This acidity is in part a function of inflammation as the pH of the EBC of patients increased significantly with treatment of an exacerbation, although not to control levels. Acidic pH of the ELF may play a role in the pathophysiology of CF lung disease and requires further investigation.

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240 Choi et al11 showed that cultured cells expressing CFTR mutations known to be associated with pancreatic sufficiency (class 4-5 mutations such as R117H, A455E) displayed significantly greater bicarbonate conductance than mutations associated with pancreatic insufficiency (class 1-3 mutations, G452X, ∆F508, G551D). Login to comment

[hide] Survey of CF mutations in the clinical laboratory. BMC Clin Pathol. 2002 Nov 19;2(1):4. Huber K, Mirkovic B, Nersesian R, Myers A, Saiki R, Bauer K
Survey of CF mutations in the clinical laboratory.
BMC Clin Pathol. 2002 Nov 19;2(1):4., 2002-11-19 [PMID:12437773]

Abstract [show]
BACKGROUND: Since it is impossible to sequence the complete CFTR gene routinely, clinical laboratories must rely on test systems that screen for a panel of the most frequent mutations causing disease in a high percentage of patients. Thus, in a cohort of 257 persons that were referred to our laboratory for analysis of CF gene mutations, reverse line probe assays for the most common CF mutations were performed. These techniques were evaluated as routine first-line analyses of the CFTR gene status. METHODS: DNA from whole blood specimens was extracted and subjected to PCR amplification of 9 exons and 6 introns of the CFTR gene. The resulting amplicons were hybridised to probes for CF mutations and polymorphisms, immobilised on membranes supplied by Roche Molecular Systems, Inc. and Innogenetics, Inc. Denaturing gradient gel electrophoresis and sequencing of suspicious fragments indicating mutations were done with CF exon and intron specific primers. RESULTS: Of the 257 persons tested over the last three years (referrals based on 1) clinical symptoms typical for/indicative of CF, 2) indication for in vitro fertilisation, and 3) gene status determination because of anticipated parenthood and partners or relatives affected by CF), the reverse line blots detected heterozygote or homozygote mutations in the CFTR gene in 68 persons (26%). Eighty-three percent of those affected were heterozygous (47 persons) or homozygous (10 persons) for the DeltaF508 allele. The only other CF-alleles that we found with these tests were the G542X allele (3 persons), the G551D allele (3 persons), the 3849+10kb C-T allele (2 persons) the R117H allele (2 persons) and the 621+1G-T allele (1 person).Of the fifteen IVS8-5T-polymorphisms detected in intron 8, seven (47%) were found in males referred to us from IVF clinics. These seven 5T-alleles were all coupled with a heterozygous DeltaF508 allele, they make up 35% of the males with fertility problems (20 men) referred to us. CONCLUSIONS: In summary, the frequency of CF chromosomes in the cohort examined with these tests was 26%, with the DeltaF508 allele affecting 83% of the CF chromosomes. It is a substantial improvement for routine CF diagnostics to have available a test system for 30 mutations plus the polypyrimidine length variants in intron 8. Our results show that this test system allows a routine first-line analyses of the CFTR gene status.

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35 All probands (or their par- Table 1: Exons and introns that are amplified with the line probe assay, and the mutations they encompass Roche assay: Amplicon Mutations exon 4 R117H,621+1G → T exon 7 R334W, R347P exon 9 A455E, 5/7/9T polymorphism exon 10 ∆1507, ∆F508. Login to comment
36 F508C, I507V, I506V polymorphism exon 11 1717-1G → A, G542X, S549N, G551D, R553X, R560T exon 20 W1282X exon 21 N1303K intron 19 3849+10kb C → T Innogenetics assay: exon 3 394delTT, G85E, E60X exon/intron 4 621+1G-T, R117H exon 7 1078delT, R347P, R334W exon 13 2143delT, 2183AA-G, 2184delA exon 19 R1162X, 3659delC intron 5 711+5G-A intron8/exon 9 A455E,, 5T,7T,9T intron 14b 2789+5G-A intron 19 3849+10kb C-T Table 2: Genotypes of patients with mutations, final results Group 1) (patients with symptoms typical for/indicative of CF) No. Login to comment

[hide] Extensive sequencing of the cystic fibrosis transm... Genet Med. 2003 Jan-Feb;5(1):9-14. Strom CM, Huang D, Chen C, Buller A, Peng M, Quan F, Redman J, Sun W
Extensive sequencing of the cystic fibrosis transmembrane regulator gene: assay validation and unexpected benefits of developing a comprehensive test.
Genet Med. 2003 Jan-Feb;5(1):9-14., [PMID:12544470]

Abstract [show]
PURPOSE: To develop a sequencing assay for the gene to identify mutations in patients with cystic fibrosis (CF). METHODS: An automated assay format was developed to sequence all exons and splice junctional sequences, the promotor region, and parts of introns 11 and 19. RESULTS: After validating the assay using 20 known samples, DNA of seven patients, four of whom were heterozygous for a known CF mutation, was sequenced. Known CF mutations were detected in seven of the eight chromosomes, and a novel missense mutation was detected in the eighth. In addition, this assay allowed 14 ambiguous results obtained using the Roche CF gold strips to be resolved. Three false-positive diagnoses were prevented; a different mutation at the same codon was identified in two patients and confirmation was provided in the remaining nine cases. CONCLUSIONS: Sequencing of the gene provides important information for CF patients and is a valuable adjunct to a carrier screening program to resolve ambiguities in panel testing.

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72 Seven of the nine involved the A455E mutation, and the remaining two involved the 1898 ϩ 1 G3A mutation. Login to comment
73 Weak positive lines for the A455E mutation were observed in five instances. Login to comment
75 Sequencing analysis revealed novel missense mutations or sequence variations in all five cases: two patients had 1508 C3T (S459F) occurring four codons upstream from A455E, two had 1496 C3T (A455 V), and one had 1520G3A (G463D). Login to comment
76 Whether these base changes represent novel CF mutations or polymorphism cannot be determined at this time, but the sequence analysis prevented the misdiagnosis of the patients as heterozygotes for A455E. Login to comment
77 In two cases there was no A455E signal in either the mutant or wild-type line. Login to comment
81 Because of these unusual results at the A455E site, we sequenced that exon for every patient previously found to be heterozygous for A455E. Login to comment
82 Ten patients were sequenced and the genotype A455E/wt was confirmed, indicating that the assay performance for this allele is acceptable when the expected intensity of the mutant band is observed. Login to comment
83 These data suggest that caution must be taken when weak A455E mutant bands are observed. Login to comment
90 Table 4 Results of sequencing of patient samples Description Prior genotype Sequencing CommentAllele 1 Allele 2 Confirmed CF wt/delta F508 delta F508 P205S Known mutation Confirmed CF wt/3849 ϩ 10 kb 3849 ϩ 10 kb L1077P Known mutation C 3 T C 3 T Confirmed CF wt/delta F508 delta F508 R1066C Known mutation Confirmed CF wt/delta F508 delta F508 D806G Novel missense Confirmed CF wt/wt 3154delG 3154delG Both parents confirmed carriers Confirmed CF delta F508/wt delta F508 G1244E Known mutation Confirmed CF wt/wt wt F191L Novel missense Borderline sweat test wt/wt wt wt Table 5 Resolution of ambiguities on linear array assay using sequencing Linear array result Resolution Weak mutant A455E line 1508 C 3 T (S459F) polymorphism or novel mutation Weak mutant A455E line 1508 C 3 T (S459F) polymorphism or novel mutation Weak mutant A455E line wt/1496 C 3 T (A455V) polymorphism or novel mutation Weak mutant A455E line wt/1496 C 3 T (A455V) polymorphism or novel mutation Weak mutant A455E line wt/1520 G 3 A (G463D) polymorphism or novel mutation No A455E mutant or wt line Homozygous 1499 T 3 C (V456A) polymorphism or novel mutation No A455E mutant or wt line Homozygous 1497 C 3 A polymorphism (no amino acid change) Weak wt 1898 ϩ 1 G 3 A line wt/E587A novel missense mutation or polymorphism Weak 1898 ϩ 1 G 3 A line wt/1898 ϩ 1 G 3 C-different mutation; G 3 C NOT G 3 A DISCUSSION The ACMG recommended panel of CF mutations has rapidly become the standard of care for US carrier screening. Login to comment
109 In fact, in our current assay an almost equal number of patients with positive mutant lines for the A455E mutation had sequence changes near the A455E locus as had true A455E mutations. Login to comment

[hide] [National program for neonatal screening for cysti... J Gynecol Obstet Biol Reprod (Paris). 2003 Feb;32(1 Suppl):1S56-60. Navarro J, Grosskopf C, Vidailhet M, Briard ML, Farriaux JP
[National program for neonatal screening for cystic fibrosis: implementation and preliminary results].
J Gynecol Obstet Biol Reprod (Paris). 2003 Feb;32(1 Suppl):1S56-60., [PMID:12592165]

Abstract [show]
Neonatal screening for cystic fibrosis was decided by the national medical authorities after a common investigation conducted by the French association ADPHE and national health insurance fund. Based on therapeutic progress and the proposed method using determination of blood immunoreactive trypsin then study of the main CF mutations, there is strong hope of effective CF detection and clinical benefit for the patients.

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46 3 Les mutations étudiées sont : 1717-1G > A - G542X - W 1282 X - N 1303 K - DF 508 (M) - 3849 + 10kbC > T - 621+1 G > T - R553X - G 551D, R117H, R1162X - R 334W - A455E - 2183 AA > G - 3659delC-- 1078 delT - D1507 - R347P - S 1251N, E60X, 2789+5G > A - 394del T - G 85 E - 1811+1.6 - Y122X - 711+1G > T - W 846 X - Y 1092 - 3272-26A > G. Login to comment

[hide] Cystic fibrosis mutation frequencies in an Irish p... Clin Genet. 2003 Feb;63(2):121-5. Devaney J, Glennon M, Farrell G, Ruttledge M, Smith T, Houghton JA, Maher M
Cystic fibrosis mutation frequencies in an Irish population.
Clin Genet. 2003 Feb;63(2):121-5., [PMID:12630958]

Abstract [show]
The incidence of cystic fibrosis (CF) at birth in Ireland is 1/1461. Neonate CF genetic testing is not routinely performed in Ireland. Currently, screening is only carried out where there is clinical evidence or a family history to suggest disease. Here we report the frequencies of common CF mutations occurring in an Irish population composed of samples collected from western, mid-western and southern regions of Ireland. Rarer CF mutations were also identified in a selected number of CF patients. In addition, a number of polymorphisms were identified, some of which are reported to be functionally and phenotypically important.

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18 In a selected cohort of 40 patients, six other common ABCC7 mutations were screened for, using PCR-REA: R347P, A455E, R1162X, 384910kbC> T, W1282X and N1303K. Login to comment
27 Samples (n 40) were screened using an in-house optimized protocol to screen for six additional mutations (R347P, A455E, R1162X, 3849 10kbC > T, W1282X and N1303K). Login to comment

[hide] Clinical characteristics and genotype analysis of ... Clin Otolaryngol Allied Sci. 2003 Apr;28(2):125-32. Cimmino M, Cavaliere M, Nardone M, Plantulli A, Orefice A, Esposito V, Raia V
Clinical characteristics and genotype analysis of patients with cystic fibrosis and nasal polyposis.
Clin Otolaryngol Allied Sci. 2003 Apr;28(2):125-32., [PMID:12680831]

Abstract [show]
The prevalence of nasal polyps in a group of paediatric patients with cystic fibrosis was prospectively studied in comparison with a control group with cystic fibrosis but without polyps. Clinical variables, including pulmonary function tests, skin testing and mucociliary transport, were carried out in both groups, as well as genotype analysis. Endoscopic intranasal evaluation identified polyps in 29 of 89 patients (33%). Statistical analysis revealed that patients with nasal polyposis had better pulmonary function, a higher rate of Pseudomonas aeruginosa colonization, more hospitalizations, and more prevalence of allergy to Aspergillus fumigatus than did the comparison group. We found no statistically different genotype distribution between the polyposis and the control group. However, it can be emphasized that the prevalence of the compound heterozygous genotype is higher in the nasal polyposis group than in controls. Our observations suggest that other genetic and environmental factors could play an important role in the development of nasal polyposis.

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19 R117H and A455E also are considered to be `mild' mutations: they are associated with better lung function.18 Moss and King11 reported that DF508 homozygosity was found more frequently in the patients undergoing sinus surgery (58%) than in a control population (48%). Login to comment
47 Analysis of mutations in the CFTR gene as tested by the multiplex polymerase chain reaction (PCR), followed by the reverse dot-blot technique, which searches for 29 of the most frequent mutations (DF508, N1303K, G542X, W1282X, 1717±1 G-A, R553X, 2183 AA-G, DI507, G551D, R560T, 3849 10kbC > T, R1162X, 3659delC, 3905insT, G85E, 621 1GT, R117H, R347P, R334W, A455E, 2789 5GA, Q552X, S1251N, 3905insT, 394delTT, E60X, 2143delT, 2184delA, 711 5G > A), and by ASO dot-blot for the following mutations: I148T, R1158X, 4016 1T, G1244E G >A.26 Statistical analysis was performed using multivariate analysis, by forward stepwise comparison; it was done to ®nd out which of the examined characteristics could be associated (P < 0.01) to nasal polyposis. Login to comment

[hide] Missense, nonsense, and neutral mutations define j... J Biol Chem. 2003 Jul 18;278(29):26580-8. Epub 2003 May 5. Pagani F, Buratti E, Stuani C, Baralle FE
Missense, nonsense, and neutral mutations define juxtaposed regulatory elements of splicing in cystic fibrosis transmembrane regulator exon 9.
J Biol Chem. 2003 Jul 18;278(29):26580-8. Epub 2003 May 5., 2003-07-18 [PMID:12732620]

Abstract [show]
Exonic sequence variations may induce exon inclusion or exclusion from the mature mRNA by disrupting exonic regulatory elements and/or by affecting a nuclear reading frame scanning mechanism. We have carried out a systematic study of the effect on cystic fibrosis transmembrane regulator exon 9 splicing of natural and site-directed sequence mutations. We have observed that changes in the splicing pattern were not related to the creation of premature termination codons, a fact that indicates the lack of a significant nuclear check of the reading frame in this system. In addition, the splice pattern could not be predicted by available Ser/Arg protein matrices score analysis. An extensive site-directed mutagenesis of the 3' portion of the exon has identified two juxtaposed splicing enhancer and silencer elements. The study of double mutants at these regulatory elements showed a complex regulatory activity. For example, one natural mutation (146C) enhances exon inclusion and overrides all of the downstream silencing mutations except for a C to G transversion (155G). This unusual effect is explained by the creation of a specific binding site for the inhibitory splicing factor hnRNPH. In fact, on the double mutant 146C-155G, the silencing effect is dominant. These results indicate a strict dependence between the two juxtaposed enhancer and silencer sequences and show that many point mutations in these elements cause changes in splicing efficiency by different mechanisms.

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83 Four of the natural substitutions, C31T (Q414X), G61A (G424S), T122G (I444S), and C155A (A455E), significantly decreased exon 9 inclusion to 48, 30, 40, and 16%, respectively, whereas only a modest decrease was evident for N418S. Login to comment
137 Identification of Regulatory Elements of Splicing in CFTR Exon 9-Three natural missense mutations with completely different effects on splicing (Q452P (A146C), which induces exon inclusion; A455E (C155A), causing exon exclusion; and V456F (G157T), with no effect) are located within 15 nucleotides. Login to comment
198 The natural mutations Q456P, A455E, and V456F correspond to A146C, C155A and G157T, respectively. Login to comment
221 WT sequence position AA change Nucleotide mutants Exon 9ϩ SR protein matrices above thresholds Disruption of preexisting sites New sites created by the mutations SC35 SR40 SF2 SR55 % WT 65 A 15 C 65 T 16 ⌬ 96 T 18 G 95 3.38 (13) G 19 A 52 A 20 G 80 C 31 Q414X T 50 A 43 G 62 SR40 0.28 (41) A 44 N414S G 59 46t49t 67 SR40 1.43 (41) G 61 G424S A 31 C 58 66g67a69g 68 SR40-1.01 (66) 3.21 (63) 2.24 (64) C 72 G 18 2.20 (67) A 63 2.01 (69) G 118 D443Y T 68 A 65 120g122a123g 96 2.24 (118) T 122 I444S G 40 A 144 G 55 T 40 C 145 G 85 A 87 A 146 G 92 3.02 (146) 2.66 (141) T 94 3.23 (143) Q452P C 96 3.46 (143) ⌬ 97 2.81 (142) 3.03 (141) G 147 T 97 C 98 2.70 (142) 3.00 (144) 2.53 (143) T 148 G 26 2.99 (142) 4.05 (143) C 90 2.49 (143) 2.47 (145) A 93 3.46 (145) T 149 C 82 2.99 (144) 3.53 (145) G 150 A 50 3.38 (148) C 62 T 151 A 65 C 67 3.00 (146) 3.15 (148) G 153 C 65 T 42 2.76 (153) G 154 T 18 C 20 C 155 A455E A 15 1.98 (152) G 3 T 5 G 156 T 10 3.59 (153) C 40 3.82 (153) G 157 V456F T 65 G 164ϩ ins 14 regulatory sequences derived from SR-specific score matrices, and the creation of novel enhancer and silencer controlling elements. Login to comment
282 For example, it appears that A455E can achieve adequate levels of chloride conduction at the cell surface (46, 47), causing only a partial CFTR protein processing defect (48). Login to comment
284 Furthermore, the modulation by the concentration of splicing factors, which have an inhibitory effect on the CFTR exon 9 (26, 49) and a specific and possibly individual variation distribution, can provide an explanation for the phenotypic and tissue-specific variability in CF patients, particularly in those carrying the A455E substitution. Login to comment

[hide] Analysis of cystic fibrosis transmembrane conducta... Am J Med Genet A. 2003 Jul 1;120A(1):72-6. Timmreck LS, Gray MR, Handelin B, Allito B, Rohlfs E, Davis AJ, Gidwani G, Reindollar RH
Analysis of cystic fibrosis transmembrane conductance regulator gene mutations in patients with congenital absence of the uterus and vagina.
Am J Med Genet A. 2003 Jul 1;120A(1):72-6., 2003-07-01 [PMID:12794695]

Abstract [show]
The relationship between cystic fibrosis transmembrane conductance regulator gene (CFTR) mutations and congenital absence of the uterus and vagina (CAUV) was examined. CFTR mutations have previously been associated with congenital bilateral absence of the vas deferens (CBAVD). CBAVD is caused by a disruption in the vas deferens, a Wolffian duct derivative. Because the embryologic development of the Mullerian ducts directly depends on the prior normal development of the Wolffian ducts, the same gene products may be necessary for normal embryologic development of both ductal systems. This study evaluated the role of CFTR mutations in the development of CAUV. DNA samples from 25 patients with CAUV were tested for the presence of 33 of the most common CFTR mutations. Protein-coding DNA fragments from the CFTR gene were amplified in vitro by the polymerase chain reaction (PCR) and analyzed for mutations using allele-specific oligonucleotide (ASO) probes. Two patients were heterozygous for CFTR mutations. One was heterozygous for the W1282X mutation and the other was heterozygous for the DeltaF508 mutation. The incidence of the 33 CFTR mutations found in the patients with CAUV (8%) was twice that found in the general population (4%), but much less than the incidence of CFTR mutations in men with CBAVD (80%). This data suggests that it is unlikely for CFTR mutations to cause CAUV in females as they cause CBAVD in some males. Furthermore, the data suggest that CAUV in females may be the same disorder as CBAVD in males who do not have CFTR mutations.

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82 CFTR Gene Mutations Tested DF508 R334W Y1092X 5T variant Y122X R347H G542X S549R 3,849 þ 4 G551D 3,849 þ 10 kb 2,789 þ 5 W1282X R553X 711 þ 1 3,905 þ T 621 þ 1 1,898 þ 1 N1303K 1,717À1 R1162X R117H 1078dT A455E D1507 Q493X 218dA R347P V520F G85E R560T S549N 3659dC Wolffian duct must occur at a time when the Mu¨llerian duct is no longer dependent on the Wolffian duct for development. Login to comment

[hide] Molecular consequences of cystic fibrosis transmem... Gut. 2003 Aug;52(8):1159-64. Ahmed N, Corey M, Forstner G, Zielenski J, Tsui LC, Ellis L, Tullis E, Durie P
Molecular consequences of cystic fibrosis transmembrane regulator (CFTR) gene mutations in the exocrine pancreas.
Gut. 2003 Aug;52(8):1159-64., [PMID:12865275]

Abstract [show]
BACKGROUND AND AIMS: We tested the hypothesis that the actual or predicted consequences of mutations in the cystic fibrosis transmembrane regulator gene correlate with the pancreatic phenotype and with measures of quantitative exocrine pancreatic function. METHODS: We assessed 742 patients with cystic fibrosis for whom genotype and clinical data were available. At diagnosis, 610 were pancreatic insufficient, 110 were pancreatic sufficient, and 22 pancreatic sufficient patients progressed to pancreatic insufficiency after diagnosis. RESULTS: We identified mutations on both alleles in 633 patients (85.3%), on one allele in 95 (12.8%), and on neither allele in 14 (1.9%). Seventy six different mutations were identified. The most common mutation was DeltaF508 (71.3%) followed by G551D (2.9%), G542X (2.3%), 621+1G-->T (1.2%), and W1282X (1.2%). Patients were categorized into five classes according to the predicted functional consequences of each mutation. Over 95% of patients with severe class I, II, and III mutations were pancreatic insufficient or progressed to pancreatic insufficiency. In contrast, patients with mild class IV and V mutations were consistently pancreatic sufficient. In all but four cases each genotype correlated exclusively with the pancreatic phenotype. Quantitative data of acinar and ductular secretion were available in 93 patients. Patients with mutations belonging to classes I, II, and III had greatly reduced acinar and ductular function compared with those with class IV or V mutations. CONCLUSION: The predicted or known functional consequences of specific mutant alleles correlate with the severity of pancreatic disease in cystic fibrosis.

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294 Less common mutations included G85E and 5T (n=5 chromosomes), A455E and R1162X (n=4 chromosomes), R347, Y1092X, R334W, and V520F (n=3 chromosomes). Login to comment

[hide] Detection of cystic fibrosis mutations by peptide ... Clin Chem. 2003 Aug;49(8):1318-30. Malehorn DE, Telmer CA, McEwen SB, An J, Kinsey AD, Retchless AC, Mason C, Vieta WM, Jarvik JW
Detection of cystic fibrosis mutations by peptide mass signature genotyping.
Clin Chem. 2003 Aug;49(8):1318-30., [PMID:12881448]

Abstract [show]
BACKGROUND: The diversity of genetic mutations and polymorphisms calls for the development of practical detection methods capable of assessing more than one patient/one nucleotide position per analysis. METHODS: We developed a new method, based on peptide mass signature genotyping (PMSG), for the detection of DNA mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Exons of the gene were amplified, cloned, and expressed in Escherichia coli as peptide fusions, in natural as well as unnatural reading frames. Peptide analytes were purified by immobilized metal affinity chromatography and analyzed by matrix-assisted, laser desorption/ionization time-of-flight mass spectrometry. Synthetic and natural DNA samples with the 25 mutations recommended for CFTR carrier screening (Grody et al. Genet Med 2001;3:149-54) were assessed using the PMSG test for the CFTR gene. RESULTS: Peptide analytes ranged from 6278 to 17 454 Da and varied 30-fold in expression; highly expressing peptides were observed by electron microscopy to accumulate as inclusion bodies. Peptides were reliably recovered from whole-cell lysates by a simple purification method. CFTR mutations caused detectable changes in resulting mass spectrometric profiles, which were >95% reliably detected in blinded testing of replicate synthetic heterozygous DNA samples. Mutation detection was possible with both sample pooling and multiplexing. The PMSG CFTR test was used to determine compound heterozygous mutations in DNA samples from cystic fibrosis patients, which were confirmed by direct DNA sequencing. CONCLUSIONS: The PMSG test of the CFTR gene demonstrates unique capabilities for determining the sequence status of a DNA target by sensitively monitoring the mass of peptides, natural or unnatural, generated from that target.

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138 ⌬b 3 R Y 9863.78 G85E SerϾPhe 9923.90 Y 60.12 4.1 R N 7047.69 R117H AlaϾVal 7075.76 N 28.07 4.2 R Y 11161.32 lI48T AsnϾSer 11134.32 Y -27.00 621ϩ1 GϾT TyrϾTAA 6513.09 N -4648.23 5 R Y 11081.45 711ϩ1 GϾT ThrϾAsn 11094.48 Y 13.03 7.1 R N 7383.08 1078⌬T frameshift 9201.10 Y 1818.02 7 R Y 12233.9 R334W ArgϾGln 12205.87 Y -28.03 R347P ArgϾGly 12134.79 Y -99.11 9 F Y 14049.68 A455E AlaϾGlu 14107.74 Y 58.06 10.2 R Y 10525.57 ⌬I507 ⌬ Asp 10410.50 Y -115.07 ⌬F508 ⌬ Asp & LysϾAsn 10396.43 Y -129.14 11.2 F Y 11173.32 1717-1 GϾA GlyϾArg 11272.46 Y 99.14 G542X TrpϾLeu 11100.27 Y -73.05 G551D no change 11173.32 Y 0.00 R553X ThrϾMet 11203.42 Y 30.10 R560T no change 11173.32 Y 0.00 11 F N 8465.27 1717-1 GϾA no change 8465.27 N 0.00 G542X GlyϾTGA 6584.17 N -1881.10 G551D GlyϾAsp 8523.33 N 58.06 R553X ArgϾTGA 7541.18 N -924.09 R560T ArgϾThr 8410.21 N -55.06 12 F Y 10372.51 1898ϩ1 GϾA GlyϾAsp 10430.57 Y 58.06 13.2A R Y 10103.23 2184⌬A frameshift 8726.91 N -1376.32 14B R Y 9291.17 2789ϩ5 GϾA LeuϾPhe 9325.21 Y 34.04 16 F N 9398.67 3120ϩ1 GϾA ValϾIle 9412.72 N 14.05 19 F Y 17455.96 R1162X ArgϾTGA 6280.13 N -11175.83 3659⌬C frameshift 9650.06 N -7805.90 19i F Y 9699.9 3849ϩ10kB CϾT ArgϾTGA 7131.04 N -2568.86 20 F N 11125.48 W1282X TrpϾTGA 9370.40 N -1755.08 21 F Y 11183.44 N1303K AsnϾLys 11197.54 Y 14.10 a Denotes the directionality of exonic sequence when expressed as peptide. Login to comment
181 The heterozygous mutations depicted are as follows: (A), exon 3 wt/G85E; (B), exon 4.1 wt/R117H; (C), exon 4.2 wt/I148T; (D), exon 4.2 wt/621 ؉ 1G>T; (E), exon 5 wt/711 ؉ 1G>T; (F), exon 7.1 wt/1078⌬T; (G), exon 7 wt/R334W; (H), exon 7 wt/R347P; (I), exon 9 wt/A455E; (J), exon 10.2 wt/⌬I507; (K), exon 10.2 wt/⌬F508; (L), exon 11.2 wt/1717-1G>A; (M), exon 11 wt/G542X; (N), exon 11 wt/G551D; (O), exon 11 wt/R553X; (P), exon 11 wt/R560T; (Q), exon 12 wt/1898 ؉ 1G>A; (R), exon 13.2A wt/2184⌬A; (S), exon 14B wt/2789 ؉ 5G>A; (T), exon 16 wt/3120 ؉ 1G>A; (U), exon 19 wt/R1162X; (V), exon 19 wt/3659⌬C; (W), intron 19 wt/3849 ؉ 10kbC>T; (X), exon 20 wt/W1282X; (Y), exon 21 wt/N1303K. typical yield of purified protein was 1-30 ␮g/test well, depending on the analyte species. Login to comment

[hide] Atypical cystic fibrosis--diagnostic and managemen... J R Soc Med. 2003;96 Suppl 43:2-10. Wallis C
Atypical cystic fibrosis--diagnostic and management dilemmas.
J R Soc Med. 2003;96 Suppl 43:2-10., [PMID:12906319]

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110 This 5T variant reduces the splicing efficiency with lower levels of functioning CFTR and thus greater clinical impact.27 The A455E mutation is mostly associated with mild pancreatic disease. Login to comment

[hide] Mutation analysis of the cystic fibrosis transmemb... Eur J Hum Genet. 2003 Sep;11(9):687-92. Perri F, Piepoli A, Stanziale P, Merla A, Zelante L, Andriulli A
Mutation analysis of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the cationic trypsinogen (PRSS1) gene, and the serine protease inhibitor, Kazal type 1 (SPINK1) gene in patients with alcoholic chronic pancreatitis.
Eur J Hum Genet. 2003 Sep;11(9):687-92., [PMID:12939655]

Abstract [show]
Susceptibility to alcoholic chronic pancreatitis (ACP) could be genetically determined. Mutations in cationic trypsinogen (PRSS1), cystic fibrosis transmembrane conductance regulator (CFTR), and serine protease inhibitor, Kazal type 1 (SPINK1) genes have been variably associated with both the hereditary and the idiopathic form of chronic pancreatitis (CP). Our aim was to analyze the three genes in ACP patients. Mutational screening was performed in 45 unrelated ACP patients and 34 patients with alcoholic liver disease (ALD). No mutation of PRSS1 was found in ACP and ALD patients. Three mutations of CFTR were detected in four ACP patients with a prevalence (8.9%) not significantly different from that observed (3.0%) in ALD patients and from that expected (3.2%) in our geographical area. Neither compound heterozygotes for CFTR nor trans-heterozygotes for CFTR/SPINK1 were found. One ACP patient (2.2%) was found to carry the most common mutation (N34S) of SPINK1 compared to none of the ALD patients (P=NS). In five other patients (two with ACP and three with ALD) other rare variants, including P55S, were found. In contrast with the hereditary and the idiopathic forms of CP, in which mutations of PRSS1, CFTR, and SPINK1 genes may occur, ACP is still a "gene(s)-orphan" disease. The supposed genetic susceptibility to ACP relies on other yet unknown gene(s) which could affect the alcohol metabolism or modulate the pancreatic inflammatory response to alcohol abuse.

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33 Mutation screening of the CFTR gene The 31 most frequent mutations (F508del, I507del, G551D, G542X, N1303K, 1717-1G4A, W1282X, R553X, R347P, R347H, R334W, 3849+10kb C4T, R117H, 621+1G4T, A455E, S549N, R560T, S549R, V520F, Q493X, 3849+ 4A4G, 1078delT, R1162X, 3659delC, 3905insT, Y122X, 2183delAA4G, 2789+5G4A, 1898+1G4A, 711+1G4T, and G85E) were examined with the polymerase chain reaction (PCR) followed by an oligonucleotide ligation assay (OLA, Applied Biosystems, Foster City, CA, USA) and finally a sequence-coded separation. Login to comment

[hide] The phenotypic consequences of CFTR mutations. Ann Hum Genet. 2003 Sep;67(Pt 5):471-85. Rowntree RK, Harris A
The phenotypic consequences of CFTR mutations.
Ann Hum Genet. 2003 Sep;67(Pt 5):471-85., [PMID:12940920]

Abstract [show]
Cystic fibrosis is a common autosomal recessive disorder that primarily affects the epithelial cells in the intestine, respiratory system, pancreas, gall bladder and sweat glands. Over one thousand mutations have currently been identified in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene that are associated with CF disease. There have been many studies on the correlation of the CFTR genotype and CF disease phenotype; however, this relationship is still not well understood. A connection between CFTR genotype and disease manifested in the pancreas has been well described, but pulmonary disease appears to be highly variable even between individuals with the same genotype. This review describes the current classification of CFTR mutation classes and resulting CF disease phenotypes. Complex disease alleles and modifier genes are discussed along with alternative disorders, such as disseminated bronchiectasis and pancreatitis, which are also thought to result from CFTR mutations.

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170 Another example of correlation between a CFTR allele and pulmonary disease is the A455E mutation, which was associated with milder lung and pancreatic disease in A455E compound heterozygotes than F508 homozygotes in Quebec (De Braekeleer et al. 1997). Login to comment

[hide] Mutations of the CFTR gene in pancreatic disease. Pancreas. 2003 Nov;27(4):332-6. Pezzilli R, Morselli-Labate AM, Mantovani V, Romboli E, Selva P, Migliori M, Corinaldesi R, Gullo L
Mutations of the CFTR gene in pancreatic disease.
Pancreas. 2003 Nov;27(4):332-6., [PMID:14576497]

Abstract [show]
INTRODUCTION: An association has been found between CFTR gene mutations and chronic pancreatitis; however, there is a lack of information about the frequency of CFTR gene mutations in acute pancreatitis and in pancreatic cancer. AIM: To prospectively evaluate the prevalence of CFTR gene mutations in acute pancreatitis, chronic pancreatitis, and pancreatic cancer. METHODOLOGY: Ninety-eight consecutive patients were studied and divided into 3 groups: 34 patients with acute pancreatitis, 46 patients with chronic pancreatitis, and 18 patients with pancreatic cancer. The mutation analysis of the CFTR gene was carried out using diagnostic commercial kits for the simultaneous detection of 29 mutations and Tn polymorphism. RESULTS: Among the 98 patients studied, 12 (12.2%) had CFTR gene mutations: 2 of the 34 patients (5.9%) with acute pancreatitis, 9 of the 46 (19.6%) with chronic pancreatitis, and 1 of the 18 (5.6%) with pancreatic cancer. All the mutations were found in heterozygosis (2 DeltaF508, 1 W1282X, and 9 T5 allele). CONCLUSION: Our prospective study adds further information about the frequency of CFTR mutations in patients with a single episode of acute pancreatitis. Furthermore, our results suggest an association of CFTR gene mutations with chronic alcoholic pancreatitis and emphasize the need for a multicenter study, possibly multinational, to conclusively establish the role of CFTR mutations as a genetic susceptibility factor for this disease.

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59 The 29 Mutations and the Tn Polymorphism Which Can Be Detected by INNO-LiPA Assays Mutation Exon/Intron (i) E60X, G85E, 394delTT 3 621 + 1G > T, R117H (i) 4, 4 711 + 5G > A (i) 5 1078delT, R347P, R334W 7 A455E, Tn (i) 8, 9 ⌬F508, ⌬I507 10 G542X, 1717-1 G > A, G551D, R553X, R560T, Q552X (i) 10, 11 2183AA > G, 2184del A, 2143delT 13 2789 + 5G > A (i) 14b R1162X, 3659delC 19 3849 + 10kbC > T (i) 19 3905insT, W1282X, S1251N 20 N1303K 21 Group 3: pancreatic cancer CFTR gene mutations were identified only in 1 of the 18 patients (5.6%) with this cancer. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... Pediatr Res. 2004 Jan;55(1):69-75. Epub 2003 Nov 6. Derichs N, Mekus F, Bronsveld I, Bijman J, Veeze HJ, von der Hardt H, Tummler B, Ballmann M
Cystic fibrosis transmembrane conductance regulator (CFTR)-mediated residual chloride secretion does not protect against early chronic Pseudomonas aeruginosa infection in F508del homozygous cystic fibrosis patients.
Pediatr Res. 2004 Jan;55(1):69-75. Epub 2003 Nov 6., [PMID:14605249]

Abstract [show]
Cystic fibrosis (CF) disease severity is characterized by a broad variability that has been attributed, in addition to the CF transmembrane conductance regulator (CFTR) genotype, to modulating factors such as CFTR-mediated residual chloride (Cl-) secretion. Moreover, CFTR has been suggested to function as a receptor for Pseudomonas aeruginosa (PA). In this study, we investigated whether or not the presence of residual Cl- secretion protects against early chronic PA colonization of patients' airways. Excluding influences on the phenotype caused by different CFTR mutations, we evaluated a cohort of F508del homozygous individuals with respect to the correlation between residual Cl- secretion and the age of onset of PA colonization as an important marker of clinical phenotype. A group with early chronic PA colonization before the age of 7 y (n = 14) was compared with a cohort that had no initial PA detection at least until the age of 13 y (n = 10). We determined the Cl- transport properties by using the intestinal current measurement in rectal suction biopsies. Residual Cl- secretion, most likely due to the CFTR Cl- channel, was observed in 63% of subjects, more frequently in early chronically PA colonized than among late or not colonized patients. These results demonstrate the presence of some active F508del-CFTR in the apical cell membrane and imply that factors other than the CFTR-mediated residual Cl- secretion determine the age of onset of PA colonization.

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9 CFTR mutations such as A455E have been reported to give rise to residual Cl-secretion and a milder disease phenotype, i.e. pancreatic sufficiency and less frequent PA colonization (2, 3). Login to comment
10 However, mildly diseased A455E heterozygous patients have been described who do not exhibit residual Cl-secretion (4). Login to comment

[hide] High allelic heterogeneity between Afro-Brazilians... Genet Test. 2003 Fall;7(3):213-8. Raskin S, Pereira L, Reis F, Rosario NA, Ludwig N, Valentim L, Phillips JA 3rd, Allito B, Heim RA, Sugarman EA, Probst CM, Faucz F, Culpi L
High allelic heterogeneity between Afro-Brazilians and Euro-Brazilians impacts cystic fibrosis genetic testing.
Genet Test. 2003 Fall;7(3):213-8., [PMID:14641997]

Abstract [show]
Cystic fibrosis (CF) is an autosomal recessive disease caused by at least 1,000 different mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). To determine the frequency of 70 common worldwide CFTR mutations in 155 Euro-Brazilian CF patients and in 38 Afro-Brazilian CF patients, we used direct PCR amplification of DNA from a total of 386 chromosomes from CF patients born in three different states of Brazil. The results show that screening for seventy mutations accounts for 81% of the CF alleles in Euro-Brazilians, but only 21% in the Afro-Brazilian group. We found 21 different mutations in Euro-Brazilians and only 7 mutations in Afro-Brazilians. The frequency of mutations and the number of different mutations detected in Euro-Brazilians are different from Northern European and North American populations, but similar to Southern European populations; in Afro-Brazilians, the mix of CF-mutations is different from those reported in Afro-American CF patients. We also found significant differences in detection rates between Euro-Brazilian (75%) and Afro-Brazilian CF patients (21%) living in the same state, Minas Gerais. These results, therefore, have implications for the use of DNA-based tests for risk assessment in heterogeneous populations like the Brazilians. Further studies are needed to identify the remaining CF mutations in the different populations and regions of Brazil.

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63 FREQUENCIES OF 70 CFTR MUTATIONS IN DIFFERENT STATES OF BRAZIL, BY CONTINENTA L GROUP CFTR mutations SC PR MG detected n n n n % n % N % DF508 53 39 54 146 47.1 8 10.5 154 39.9 G542X 6 9 8 23 7.4 1 1.3 24 6.2 R1162X 9 2 4 15 4.8 2 2.6 17 4.4 N1303K 5 5 0 10 3.2 0 0 10 2.6 R334W 5 1 4 10 3.2 0 0 10 2.6 G85E 2 2 4 8 2.6 1 1.3 9 2.3 1717-1G®A 1 3 2 6 1.9 0 0 6 1.6 W1282X 4 1 1 6 1.9 0 0 6 1.6 3849110kbC®T 1 3 1 5 1.6 0 0 5 1.3 R553X 0 2 0 2 0.7 0 0 2 0.5 1812-1G®A 0 1 3 4 1.3 1 1.3 5 1.3 2183AA®G 2 1 0 3 1.0 0 0 3 0.8 312011G®A 0 0 2 2 0.7 2 2.6 4 1.0 Y1092X 0 1 1 2 0.7 1 1.3 3 0.8 G551D 0 0 0 0 0 0 0 0 0 W1089X 0 0 1 1 0.3 0 0 1 0.3 6211G®T 0 1 0 1 0.3 0 0 1 0.3 Q1238X 0 1 0 1 0.3 0 0 1 0.3 711-1G®T 0 1 0 1 0.3 0 0 1 0.3 R347P 1 0 0 1 0.3 0 0 1 0.3 189811G®A 1 0 0 1 0.3 0 0 1 0.3 I507 0 0 1 1 0.3 0 0 1 0.3 Subtotal 91 73 86 250 80.7 16 21.1 266 68.9 Alleles with CFTR 5 27 28 60 19.4 60 79.0 120 31.1 mutations not detected Total 96 100 114 310 100.0 76 100.0 386 100.0 Detection rate (%) 94.8 73.0 75.4 250 80.7 16 21.1 266 68.9 The following 70 CFTR mutations were selected and tested on the basis of frequency in various populations, known association with CF, or predicted deleterious effect on the CFTR protein product; DF508, G542X, N1303K, G551D, R553X, DI507, A455E, A559T, C524X, D1270N, E60X, G178R, G330X, G85E, 2307insA, I148T, K710X, P574H, Q1238X, Q493X, Q890X, R1158X, R1162X, R117H, R334W, R347H, R347P 2307insA, I148T, K710X, P574H, Q1238X, Q493X, Q890X, R1158X, R1162X, R117H, R334W, R347H, R347P 2307insA, 1148T, K710X, P574H, Q1238X, Q493X, Q890X, R1158X, R1162X, R117H, R334W, R347H, R347P, R352Q, R560T, S1196X, S1255X, S364P, S549N, S549R, V520F, W1089X, W1282X, W1310X, W1316X, Y1092X, Y122X, Y563D, 1078delT,1677delTA,1717-1G-A,1812-1G-A,1898 1 1G-A, 2043delG,2183delAA-G, 2184delA, 2789 1 5G-A, 2869insG, 2909delT, 3120 1 1G-A, 3120G-A, 3358delAC, 3659delC, 3662delA, 3750delAG, 3791delC, 3821delT, 3849 1 10KbC-T, 3849 1 4A-G, 3905insT, 405 1 1G-A, 444delA, 556delA, 574delA, 621 1 1G-T, and 711 1 1G-T. aSC, Santa Catarina State; PR, Parana State; MG, Minas Gerais State; n, number of chromosomes. Login to comment

[hide] Emerging drug treatments for cystic fibrosis. Expert Opin Emerg Drugs. 2003 Nov;8(2):523-35. Zeitlin PL
Emerging drug treatments for cystic fibrosis.
Expert Opin Emerg Drugs. 2003 Nov;8(2):523-35., [PMID:14662004]

Abstract [show]
Cystic fibrosis (CF) is one of the most common life-shortening inherited disorders. Mutations in the cystic fibrosis transmembrane regulator (CFTR) gene disrupt the localisation and function of the cAMP-mediated chloride channel. Most of the morbidity and mortality arise from the lung disease which is characterised by excessive inflammation and chronic infection. Research into the mechanisms of wild-type and mutant CFTR biogenesis suggest that multiple drug targets can be identified. This review explores the current understanding of the nature of the different mutant CFTR forms and the potential for repair of the chloride channel defect. High-throughput screening, pharmacogenomics and proteomics bring recent technological advances to the field.

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66 Examples of Class 5 mutations include 3849 + 10 kB C→T, A455E or 2789 + 5 G→A. Login to comment
88 Class of mutation Molecular mechanism Pancreatic status (if known) Examples 1 No CFTR protein synthesis PI W1282X, G542X, R553X, 621 + 1 G→T, 1717-1 G→A, 3905insT, 394delTT 2 Abnormal CFTR processing and trafficking PI ∆F508, N1303K, P574H 3 Defective CFTR regulation (normal trafficking) PI G551D, G551S, G1349D, S1255P 4 Decreased CFTR chloride conductance PS R117H, R334W, R347P, P547H 5 Reduced synthesis and trafficking of normal CFTR PS A455E, 3849 + 10kb C→T, (5T) 6A Reduced apical stability PI S1455X, Q1412S, 4326delTC, 4279insA 6B Defective regulation of other ion channels PI G551D Note that the G551D is placed in Class 3 for defective regulation and Class 6B for defective regulation of the outwardly rectifying chloride channel. Login to comment

[hide] Structure of nucleotide-binding domain 1 of the cy... EMBO J. 2004 Jan 28;23(2):282-93. Epub 2003 Dec 18. Lewis HA, Buchanan SG, Burley SK, Conners K, Dickey M, Dorwart M, Fowler R, Gao X, Guggino WB, Hendrickson WA, Hunt JF, Kearins MC, Lorimer D, Maloney PC, Post KW, Rajashankar KR, Rutter ME, Sauder JM, Shriver S, Thibodeau PH, Thomas PJ, Zhang M, Zhao X, Emtage S
Structure of nucleotide-binding domain 1 of the cystic fibrosis transmembrane conductance regulator.
EMBO J. 2004 Jan 28;23(2):282-93. Epub 2003 Dec 18., 2004-01-28 [PMID:14685259]

Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a chloride channel. Nucleotide-binding domain 1 (NBD1), one of two ABC domains in CFTR, also contains sites for the predominant CF-causing mutation and, potentially, for regulatory phosphorylation. We have determined crystal structures for mouse NBD1 in unliganded, ADP- and ATP-bound states, with and without phosphorylation. This NBD1 differs from typical ABC domains in having added regulatory segments, a foreshortened subdomain interconnection, and an unusual nucleotide conformation. Moreover, isolated NBD1 has undetectable ATPase activity and its structure is essentially the same independent of ligand state. Phe508, which is commonly deleted in CF, is exposed at a putative NBD1-transmembrane interface. Our results are consistent with a CFTR mechanism, whereby channel gating occurs through ATP binding in an NBD1-NBD2 nucleotide sandwich that forms upon displacement of NBD1 regulatory segments.

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216 CF mutations in NBD1 The majority of sites of CF-causing missense mutations occur in NBD1, primarily in its a-subdomain, and the locations in the mNBD1 structure of the most common of these (A455E, G480C, I506T, DI507, DF508, S549N, S549R, G551D, A559T, R560T, Y569D, and D648V; Bobadilla et al, 2002) are shown in Figure 3D. Login to comment

[hide] CFTR gene and cystic fibrosis. J Gastroenterol Hepatol. 2004 Feb;19(2):228. Gaskin KJ
CFTR gene and cystic fibrosis.
J Gastroenterol Hepatol. 2004 Feb;19(2):228., [PMID:14731137]

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7 In contrast, patients with at least one copy of type IV and V mutations, for example R117H or A455E, usually have sufficient preservation of their exocrine pancreatic function to prevent malabsorption and are classified as pancreatic sufficient. Login to comment

[hide] Neonatal screening for cystic fibrosis: France ris... J Inherit Metab Dis. 2003;26(8):729-44. Farriaux JP, Vidailhet M, Briard ML, Belot V, Dhondt JL
Neonatal screening for cystic fibrosis: France rises to the challenge.
J Inherit Metab Dis. 2003;26(8):729-44., [PMID:14739679]

Abstract [show]
This paper describes the adjustments to the French neonatal screening programme required by the introduction of systematic screening for cystic fibrosis (CF), taking into account both the legal and statutory framework and the lessons of a pilot study carried out 10 years ago. The French association for the screening and prevention of infant handicaps (AFDPHE) has been mandated by its regulatory agencies to organize screening for CF in France (metropolitan and overseas territories). During the year 2001, expert groups (Technical Aspects, Information, Ethics and Genetics, Criteria for CF Centres, Protocol for the Care of a Newborn with CF) issued recommendations for the establishment of a national programme that would guarantee efficiency and adequate patient care from the time of diagnosis onward. The programme is based on a strategy combining immunoreactive trypsin (IRT) assay and the analysis of DNA mutations in dried blood samples obtained at 3 days of age. When an elevated IRT value is found, DNA analysis is performed on the same sample. Owing to the relative regional heterogeneity existing in France, 30 selected mutations are used, which provide 85% coverage. The Ethics and Genetics Committee recommended that, in order to avoid arousing anxiety by a recall, informed consent, according to the French legislation on bioethics, should be obtained for all neonates at birth by having the parents sign directly on the sampling paper. Information brochures for parents and health professionals have been designed. A new organization of patient care, involving the creation of CF centres recognized by the Ministry of Health, has been decided; all children diagnosed are to be referred to such centres, where they can be well cared for by a trained staff with sufficient means. The programme was implemented region by region in France, from the beginning of the year 2002 to early 2003. The expert groups still meet periodically to evaluate the implementation of the programme and to check that the terms of the agreement between the AFDPHE and the Social Security Agency are complied with.

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114 In its present version, the kit allows screening for 20 CFTR gene mutations (F508del, G542X, N1303K, 1717-1G>A, G551D, W1282X, R553X, I507del, 1078delT, 2183AA>G, 3849 þ 10kbC>T, R1162X, 621 þ 1G>T, R334W, R347P, 3659delC, R117H, S1251N, E60X, A455E) in one workday; moreover, it does not require any speci'c equipment. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... Hum Reprod. 2004 Feb;19(2):250-3. Wu CC, Hsieh-Li HM, Lin YM, Chiang HS
Cystic fibrosis transmembrane conductance regulator gene screening and clinical correlation in Taiwanese males with congenital bilateral absence of the vas deferens.
Hum Reprod. 2004 Feb;19(2):250-3., [PMID:14747162]

Abstract [show]
BACKGROUND: In Taiwan, an area with a very low incidence of cystic fibrosis (CF), we first screened for the most common mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene and looked for clinical correlations in 27 patients with clinically diagnosed congenital bilateral absence of the vas deferens (CBAVD). METHODS AND RESULTS: The clinical results showed that none of the 27 patients had CF symptoms. We did not detect any definite renal anomaly ultrasonographically. Mutation analysis was carried out on these 27 cases and 46 normal fertile males as controls. No mutations of Delta F508 or R117H were identified in any of the samples analysed. In the screening of IVS8-poly T, five of the 27 CBAVD patients showed the homozygous genotype for 5T/5T, 14 showed the heterozygous genotype for 5T/7T and eight showed the homozygous genotype for 7T/7T. The frequency of 5T alleles was 44.4%, which was significantly higher than in the 46 normal fertile males, for which there was a 5T frequency of 5.4%. CONCLUSIONS: The absence of major mutations of CFTR genes could be related to the much lower CF incidence in Taiwan. Further investigations into differences in the mutation spectrum of other CFTR genes are needed for a better understanding of the development of Taiwanese-Oriental CBAVD.

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42 Screening by an INNO-LiPA CFTR17+Tn kit For further con®rmation, we used a commercial kit (INNO-LiPA CFTR17+Tn; Innogenetics, Ghent, Belgium) that allowed the detection of 17 mutations (including 394delTT, G85E, E60X, 621+1G®T, R117H, 711+5G®A, 1078delT, R347P, R334W, A455E, 2143delT, 2183AA®G, 2184delA, 2789+5G®A, R1162X, 3659delC and 3849+10kbC®T) associated with IVS8-Tn polymorphisms (5T/7T/9T) in the CFTR gene to analyse our 27 patients and 46 normal, fertile control males. Login to comment

[hide] Improved detection of cystic fibrosis mutations in... Hum Reprod. 2004 Mar;19(3):540-6. Epub 2004 Jan 29. Danziger KL, Black LD, Keiles SB, Kammesheidt A, Turek PJ
Improved detection of cystic fibrosis mutations in infertility patients with DNA sequence analysis.
Hum Reprod. 2004 Mar;19(3):540-6. Epub 2004 Jan 29., [PMID:14998948]

Abstract [show]
BACKGROUND: Accurate determination of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is critical for genetic counselling and treatment of obstructive azoospermia. Of concern is that detection rates with routine CFTR mutation panels vary widely depending on patient ancestry; and such panels have limited value for azoospermic patients, who are more likely to carry rare mutations. An alternative approach offers comprehensive, CFTR mutation analysis by a DNA sequence method. We investigated whether this method could improve CFTR detection rates in men with obstructive azoospermia in a prospective study of men with obstructive azoospermia and their partners who were referred for genetic counselling and testing at one of two institutions. METHODS: Sixteen patients with congenital absence of the vas deferens (CAVD, n = 14) or idiopathic obstructive azoospermia (n = 2) were studied. DNA from all patients was analysed for mutations by the DNA sequence method. In addition to this method, six men underwent CFTR analysis by a common 25 or 31 mutation panel coupled with poly T analysis. In 10 subjects, common mutation panel findings were inferred from DNA sequence method results. RESULTS: Overall, 12/16 (75%) azoospermic patients had one or more CFTR mutations and/or 5T alleles, including 12 mutations in 10 patients (two compound heterozygotes) and seven 5T alleles in six patients (one homozygote). The sequence method detected all mutations and three variants of unknown significance. By comparison, the common mutation panels detected only 3/12 mutations (25%) and 0/3 variants. CONCLUSION: The DNA sequence method detects more CFTR mutations than common mutation panels. Given the serious, clinical consequences of transmitting such mutations, this study underscores the importance of accurate, CFTR mutation detection in men with obstructive azoospermia and their partners.

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59 Polyacrylamide gels were analysed for the presence of mutations following staining in ethidium bromide (EtBr) and image capture under UV using the Gel Doc 1000 system Table I. List of CFTR mutations included in common mutation panels American College of Medical Genetics CF panel (25 mutations) DF508 G542X G551D R117H W1282X N1303K R1162X 3849+10kbC®T DI507 R553X 1717-1G®A 621+1G®T R560T 3659delC 3120+1G®A I148T G85E R334W A455E 1898+1G®A 2148delA 711+1G®T 2789+5G®A R347P 1078delT Six additional mutations and one polymorphism in UCSF panel (31 mutations) Y1092X R347H 3849+4 Q493X 3905insT S549N F508C (polymorphism) (BioRad). Login to comment

[hide] Direct visualization of cystic fibrosis transmembr... Clin Chem. 2004 May;50(5):836-45. Epub 2004 Mar 9. Strom CM, Clark DD, Hantash FM, Rea L, Anderson B, Maul D, Huang D, Traul D, Chen Tubman C, Garcia R, Hess PP, Wang H, Crossley B, Woodruff E, Chen R, Killeen M, Sun W, Beer J, Avens H, Polisky B, Jenison RD
Direct visualization of cystic fibrosis transmembrane regulator mutations in the clinical laboratory setting.
Clin Chem. 2004 May;50(5):836-45. Epub 2004 Mar 9., [PMID:15010427]

Abstract [show]
BACKGROUND: The recommendation for population- based cystic fibrosis (CF) carrier screening by the American College of Medical Genetics for the 25 most prevalent mutations and 6 polymorphisms in the CF transmembrane regulatory gene has greatly increased clinical laboratory test volumes. We describe the development and technical validation of a DNA chip in a 96-well format to allow for high-throughput genotype analysis. METHODS: The CF Portrait chip contains an 8 x 8 array of capture probes and controls to detect all requisite alleles. Single-tube multiplex PCR with 15 biotin-labeled primer pairs was used to amplify sequences containing all single-nucleotide polymorphisms to be interrogated. Detection of a thin-film signal created by hybridization of multiplex PCR-amplified DNA to complementary capture probes was performed with an automated image analysis instrument, NucleoSight. Allele classification, data formatting, and uploading to a laboratory information system were fully automated. RESULTS: The described platform correctly classified all mutations and polymorphisms and can screen approximately 1300 patient samples in a 10-h shift. Final validation was performed by two separate 1000-sample comparisons with Roche CF Gold line probe strips and the Applera CF OLA, Ver 3.0. The CF Portrait Biochip made no errors during this validation, whereas the Applera assay made seven miscalls of the IVS-8 5T/7T/9T polymorphism CONCLUSIONS: The CF Portrait platform is an automated, high-throughput, DNA chip-based assay capable of accurately classifying all CF mutations in the recommended screening panel, including the IVS-8 5T/7T/9T polymorphism.

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178 The optimal spotting conditions for each probe are indicated by the boxes around spots in C. wild-type controls and heterozygotes for each ACMG mutation and polymorphism, DNA from 12 compound heterozygotes (⌬F508/1898 ϩ 1GϾA, 711 ϩ 1GϾT/⌬F508, G85E/621 ϩ 1GϾT, 3659delC/⌬F508, 3120 ϩ 1GϾA/ 621 ϩ 1GϾT, R347P/G551D, A455E/⌬F508, R560T/ dF508, R553X/⌬F508, 621 ϩ 1GϾT/⌬F508, 621 ϩ 1GϾT/ 711 ϩ 1GϾT, R117H/⌬F508, and I506V/⌬F508) and DNA from 4 homozygous patients (⌬F508 and 2789 ϩ 5GϾA, 3849 ϩ 10kbCϾT, and G542X) was used in validation experiments. Login to comment
199 In this series, there were 17 ⌬F508 heterozygous patient samples, 1 ⌬F508 homozygous sample, 2 R117H heterozygous samples, and 1 heterozygous patient sample each for I148T, G542X, R553X, R347P, and 2789 ϩ 5GϾA, for a total of 26 mutant alleles. Additional mutant alleles detected in the control samples included three fixed control samples (⌬F508 homozygous, 5T/WT, 3659delC/⌬F508) on every plate and two heterozygous samples (R560T and 1078delT) and one heterozygous sample each for R334W, A455E, R347P, R117H, ⌬I507, I507V, G551D, and 1717-1GϾA as rotating controls. Login to comment

[hide] Role of CFTR mutations in adult bronchiectasis. Thorax. 2004 Apr;59(4):357-8. King PT, Freezer NJ, Holmes PW, Holdsworth SR, Forshaw K, Sart DD
Role of CFTR mutations in adult bronchiectasis.
Thorax. 2004 Apr;59(4):357-8., [PMID:15047968]

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230 The patients were screened for the 10 most common mutations in the local population (DF508, D1507, V520F, G542X, G551D, R553X, R117H, 621+1GRT, A455E and N1303K) responsible for 82% of cases of CF and the 5T mutation by previously published methods.7 8 Ethical approval for the project was obtained from the ethics committee at MMC. Login to comment

[hide] A finger sweat chloride test for the detection of ... Pancreas. 2004 Apr;28(3):e80-5. Naruse S, Ishiguro H, Suzuki Y, Fujiki K, Ko SB, Mizuno N, Takemura T, Yamamoto A, Yoshikawa T, Jin C, Suzuki R, Kitagawa M, Tsuda T, Kondo T, Hayakawa T
A finger sweat chloride test for the detection of a high-risk group of chronic pancreatitis.
Pancreas. 2004 Apr;28(3):e80-5., [PMID:15084988]

Abstract [show]
OBJECTIVES: Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene are associated with chronic pancreatitis in Caucasians. We developed a simple method for measuring finger sweat chloride concentration to test whether CFTR dysfunction underlies chronic pancreatitis in Japan where cystic fibrosis (CF) is rare. METHODS: We studied 25 patients with chronic (21 alcoholic and 4 idiopathic) pancreatitis and 25 healthy volunteers. Sweat chloride concentrations were measured by a finger sweat chloride test. We analyzed DNA for 20 common CFTR mutations in Europeans, 9 CF-causing mutations in Japanese, and 2 polymorphic loci, a poly-T tract and (TG) repeats, at intron 8. RESULTS: Thirteen patients (52%) had sweat chloride levels >60 mmol/L, a level consistent with CF, while only 4 (16%) healthy subjects exceeded this level. The 29 CF mutations and the 5T allele were detected in neither the patients nor controls. The (TG) 12 allele was common in both the patients (58%) and controls (48%). The (TG) 12/12 genotype was common in alcoholic pancreatitis (29%) compared with the (TG) 11/11 (10%). Patients with the (TG) 12/12 genotype had significantly higher sweat chloride concentrations than the controls. CONCLUSION: CFTR dysfunction as evidenced by a finger sweat chloride test is present in about half of Japanese patients with chronic pancreatitis, suggesting that this test may be useful for detecting the high-risk group. A higher proportion of the (TG) 12 allele may be a genetic background for elevated sweat chloride concentrations in Japanese patients.

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50 The DNA samples were analyzed using an amplification refractory mutation system kit for 20 common major CFTR mutations (E60X, R117H, R334W, R347P, A455E, ⌬I507, ⌬F508, G542X, G551D, R553X, 621+1G>T, 1078delT, R1162X, S1251N, W1282X, N1303K, 1717-1G>A, 2183AA>G, 3659delC, 3849+10kbC>T) (Elucigene CF 20, AstraZeneca Diagnostics, Abingdon, UK) following the standard procedures recommended by the manufacturer. Login to comment

[hide] Genetic evidence for CFTR dysfunction in Japanese:... J Med Genet. 2004 May;41(5):e55. Fujiki K, Ishiguro H, Ko SB, Mizuno N, Suzuki Y, Takemura T, Yamamoto A, Yoshikawa T, Kitagawa M, Hayakawa T, Sakai Y, Takayama T, Saito M, Kondo T, Naruse S
Genetic evidence for CFTR dysfunction in Japanese: background for chronic pancreatitis.
J Med Genet. 2004 May;41(5):e55., [PMID:15121783]

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218 The 20 most common CF mutations (E60X, R117H, R334W, R347P, A455E, DI507, DF508, G542X, G551D, R553X, 621+1GRT, 1078delT, R1162X, S1251N, W1282X, N1303K, 1717-1GRA, 2183AARG, 3659delC, and 3849+10kbCRT) were tested by an Elucigene CF20 kit (AstraZeneca Diagnostics, Abingdon, Oxfordshire, UK). Login to comment

[hide] Rescuing cystic fibrosis transmembrane conductance... Proc Natl Acad Sci U S A. 2004 May 25;101(21):8221-6. Epub 2004 May 12. Cormet-Boyaka E, Jablonsky M, Naren AP, Jackson PL, Muccio DD, Kirk KL
Rescuing cystic fibrosis transmembrane conductance regulator (CFTR)-processing mutants by transcomplementation.
Proc Natl Acad Sci U S A. 2004 May 25;101(21):8221-6. Epub 2004 May 12., 2004-05-25 [PMID:15141088]

Abstract [show]
Most cases of cystic fibrosis (CF) are caused by mutations that block the biosynthetic maturation of the CF gene product, the CF transmembrane conductance regulator (CFTR) chloride channel. CFTR-processing mutants fail to escape the endoplasmic reticulum and are rapidly degraded. Current efforts to induce the maturation of CFTR mutants target components of the biosynthetic pathway (e.g., chaperones) rather than CFTR per se. Such methods are inherently nonspecific. Here we show that the most common CF-causing mutant (DeltaF508-CFTR) can form mature, functional chloride channels that reach the cell surface when coexpressed with several other CFTR-processing mutants or with amino fragments of the wild-type CFTR protein. This transcomplementation effect required a specific match between the region flanking the disease-causing mutation and the complementing fragment; e.g., amino fragments complemented DeltaF508-CFTR but not H1085R (a carboxy-processing mutant), whereas a carboxy fragment complemented H1085R but not DeltaF508-CFTR. Transcomplementing fragments did not affect CFTR interactions with Hsc70, a chaperone previously implicated in CFTR biosynthesis. Instead, they may promote CFTR maturation by blocking nonproductive interactions between domains within the same or neighboring CFTR polypeptides that prevent normal processing. These findings indicate that it may be possible to develop CF therapies (e.g., mini-cDNA constructs for gene therapy) that are tailored to specific disease-causing mutants of CFTR.

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128 To gauge the potential physiologic significance of this transcomplementation effect, we compared the transport activity and the amount of mature ⌬F508-CFTR protein that could be induced by transcomplementation to that observed for a partial processing mutant that associates with mild CF (A455E) (21). Login to comment
129 Although the transport activity and the amount of mature protein for the rescued ⌬F508-CFTR was considerably less than that observed for wild-type CFTR, both parameters were similar to that detected for the A455E mutant (Fig. 3 C and D). Login to comment
130 The A455E mutant associates with a mild phenotype presumably because it retains partial function [it has been reported that only 5-10% of ''normal`` CFTR activity is required to prevent severe disease (22, 23)]. Login to comment
160 (C) Rescued ⌬F508-CFTR exhibits macroscopic transport activity comparable to that of A455E-CFTR, a partial processing mutant associated with mild disease. Login to comment
163 (Inset) Enlarged view of the permeability responses of cells transfected with A455E () or cotransfectedwithfragment1-633and⌬F508-CFTR(ƒ)tothecAMPmixture. Login to comment
164 (D) Biochemical analysis of the band C forms of transcomplemented ⌬F508-CFTR and A455E-CFTRintransfectedCOS-7cells.Cellswereanalyzedforproteinexpression 48 h after transfection as described in Methods. Login to comment

[hide] Population-based newborn screening for genetic dis... Pediatrics. 2004 Jun;113(6):1573-81. Comeau AM, Parad RB, Dorkin HL, Dovey M, Gerstle R, Haver K, Lapey A, O'Sullivan BP, Waltz DA, Zwerdling RG, Eaton RB
Population-based newborn screening for genetic disorders when multiple mutation DNA testing is incorporated: a cystic fibrosis newborn screening model demonstrating increased sensitivity but more carrier detections.
Pediatrics. 2004 Jun;113(6):1573-81., [PMID:15173476]

Abstract [show]
OBJECTIVES: Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (DeltaF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing). METHODS: We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at approximately 2 days of age was studied. RESULTS: A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely "genetic diagnosis" was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with DeltaF508 alone. Increased sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with DeltaF508 alone. CONCLUSIONS: Use of multiple-CFTR-mutation testing improved sensitivity and postscreening prediction of CF at the cost of increased referrals and carrier identification.

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79 The 16-mutation panel included ⌬F508, R117H, G551D, G542X, W1282X, N1303K, R334W, 621 ϩ 1GϾT, R553X, ⌬I507, 1717-1GϾA, R347P, R560T, 3849 ϩ 10kbCϾT, A455E, and S549N. Login to comment
159 Genotypes and Frequencies Observed in 112 CF-Affected Infants First Mutation Second Mutation N ⌬F508 ⌬F508 55 ⌬F508 R117H 7* ⌬F508 G551D 4 ⌬F508 N1303K 3 ⌬F508 W1282X 3 ⌬F508 G542X 2 ⌬F508 1898 ϩ 1 G Ͼ A 2 G85E R117C 2 ⌬F508 1717-GϾA 1 ⌬F508 3849 ϩ 10kbC Ͼ T 1 ⌬F508 R1066C 1 ⌬F508 Y1092X 1 ⌬F508 L206W 1 ⌬F508 R560T 1 ⌬F508 1152H 1 ⌬F508 621 ϩ 1G Ͼ T 1 R117H G551D 1 R117H G85E 1 G551D 2789 ϩ 5GϾA 1 G551D R117C 1 G85E 711 ϩ 1GϾT 1 W1282X 3849 ϩ 10kbCϾT 1 R553X 2183AAϾG 1 A455E S549R 1 ⌬F508 Unknown† 13 N1303K Unknown 2 G542X Unknown 1 Unknown Unknown 2 * Includes 1 of the false-negative screens. Login to comment

[hide] Genotype/phenotype correlation of the G85E mutatio... Eur Respir J. 2004 May;23(5):679-84. Decaestecker K, Decaestecker E, Castellani C, Jaspers M, Cuppens H, De Boeck K
Genotype/phenotype correlation of the G85E mutation in a large cohort of cystic fibrosis patients.
Eur Respir J. 2004 May;23(5):679-84., [PMID:15176679]

Abstract [show]
In this European study, the phenotype in 68 patients, homozygous or compound heterozygous for the G85E mutation, was investigated. Each index case was compared with two cystic fibrosis (CF) patients from the same clinic, matched for age and sex: one with pancreatic sufficiency (PS) and one with pancreatic insufficiency (PI). When comparing 31 G85E/F508del and F508del/F508del patients, there were no differences in median age at diagnosis, mean sweat chloride value, most recent weight for height, most recent forced expiratory volume in one second % predicted, prevalence of chronic Pseudomonas aeruginosa colonisation and typical CF complications. However, PI was less frequent in the G85E/F508del group. Comparison of 55 G85E patients (with second mutation known and not classified as mild) with PS controls (n=44) showed that the G85E patients had a significantly higher sweat chloride, more often failure to thrive at diagnosis, higher prevalence of PI, worse current weight for height, higher prevalence of chronic P. aeruginosa colonisation and liver cirrhosis. Pulse-chase experiments revealed that G85E cystic fibrosis transmembrane conductance regulator failed to mature on a M470 as well as on a V470 background. Therefore, G85E is a class II mutation. Although there is variability in its clinical presentation, G85E mutation results in a severe phenotype.

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138 In patients carrying mutations such as R117H, A455E, R334W and 3849z10 kb CwT, which are reported to correlate with a milder phenotype, 40-87% have PS [21, 27]. Login to comment

[hide] Risk of pancreatitis with mutation of the cystic f... Am J Gastroenterol. 2004 Jul;99(7):1358-63. Choudari CP, Imperiale TF, Sherman S, Fogel E, Lehman GA
Risk of pancreatitis with mutation of the cystic fibrosis gene.
Am J Gastroenterol. 2004 Jul;99(7):1358-63., [PMID:15233679]

Abstract [show]
BACKGROUND: Between 5% and 15% of patients with recurrent pancreatitis have no identified etiology after routine investigation and advanced endoscopic evaluation. OBJECTIVE: To determine whether mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene is a risk factor for idiopathic pancreatitis. METHODS: We compared the frequency of CFTR mutations as measured by DNA probe analysis in a case group of persons with idiopathic pancreatitis and a control group without pancreatitis, all of whom underwent endoscopic retrograde cholangiopancreatography. A separate analysis compared the prevalence of CFTR mutations between the case group and controls with pancreatitis of known etiology. A subgroup comparison was made between cases of pancreas divisum with pancreatitis and controls with pancreas divisum and no pancreatitis. RESULTS: CFTR mutations were present in 19 (19%) of 96 cases and 7 (3.5%) of 198 controls without pancreatitis (odds ratio, OR = 6.7; 95% CI, 2.8-16.3; p < 0.00001). Compared to the controls with a known cause of pancreatitis (N = 78), cases had a higher prevalence of CFTR mutations (19% vs 2.6%, OR = 9.4; CI, 2.1-41.7; p= 0.0005). Among subjects with pancreas divisum, CFTR mutations were present in 8 (22%) of 37 cases compared to 0 (0%) of 20 controls (OR = 11.8; CI, 8.9-14.7; p= 0.02). CONCLUSION: The risk of idiopathic pancreatitis is greater among persons with CFTR mutations as compared to persons without CFTR mutations. Among persons with pancreas divisum, CFTR mutations appear to increase the risk for pancreatitis.

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130 In a study of more than 500 CF patients, five mutations (R117H, R334W, R347P, A455E, and P574H) were found exclusively in pancreatic sufficient patients (8). Login to comment

[hide] The role of CFTR and SPINK-1 mutations in pancreat... AIDS. 2004 Jul 23;18(11):1521-7. Felley C, Morris MA, Wonkam A, Hirschel B, Flepp M, Wolf K, Furrer H, Battegay M, Bernasconi E, Telenti A, Frossard JL
The role of CFTR and SPINK-1 mutations in pancreatic disorders in HIV-positive patients: a case-control study.
AIDS. 2004 Jul 23;18(11):1521-7., 2004-07-23 [PMID:15238770]

Abstract [show]
OBJECTIVE: Pancreatic disorders in HIV-positive patients are frequent. CFTR and SPINK-1 mutations have been reported to increase the risk of pancreatitis, but no data are available in HIV-positive patients. This study will evaluate the frequency of CFTR mutations and SPINK-1 polymorphisms in HIV-positive patients with clinical pancreatitis or asymptomatic elevation of serum pancreatic enzymes. METHOD: Cases (patients with hyperamylasemia) were identified during a toxicity study conducted in August 1999 among 1152 participants of the Swiss HIV Cohort Study. We designed a case-control study in which each case was matched one to one to an HIV-infected control according to sex, age, CD4 cell count, viraemia and medication use. CFTR mutations and SPINK-1 polymorphisms were studied using polymerase chain reaction techniques. RESULTS: Fifty-one HIV-positive patients with hyperamylasemia were detected among 1152 participants in the toxicity study (4.4%). There were 13 carriers of CFTR and SPINK-1 mutations (12.7%). Amylase levels were 316 +/- 130 U/l for the group with mutations, and 135 +/- 18 U/l for non-carriers (P = 0.79). However, among patients with hyperamylasemia, those with CFTR or SPINK-1 mutations had 648 +/- 216 U/l amylase levels compared with 232 +/- 28 U/l for those without (P = 0.025). Ten patients had acute pancreatitis, four of whom had CFTR mutations or SPINK-1 polymorphisms (40%) compared with seven of the control patients (14%) (P = 0.01). CONCLUSION: CFTR mutations and SPINK-1 polymorphisms are frequent among HIV-positive patients suffering from acute pancreatitis. These mutations may increase the susceptibility to pancreatitis when exposed to environmental risk factors.

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42 Samples were tested: (i) for 20 common CFTR mutations (delF508, 621+1G.T, G542X, 3849+10kbC.T, N1303K, 3659delC, 1717-1G.A, 1078delT, W1282X, R347P, G551D, A455E, R553X, S1251N, R1162X, delF507, R334W, 2183AA.G, R117H, and E60X; Elucigene CF20; Orchid Biosciences, Abingdon, UK); (ii) for the CFTR IVS8 5T variant (Elucigene CF Poly-T; Orchid); and (iii) for the SPINK-1 N34S polymorphism, by poly- Copyright (c) Lippincott Williams & Wilkins. Login to comment

[hide] Relation of sweat chloride concentration to severi... Pediatr Pulmonol. 2004 Sep;38(3):204-9. Davis PB, Schluchter MD, Konstan MW
Relation of sweat chloride concentration to severity of lung disease in cystic fibrosis.
Pediatr Pulmonol. 2004 Sep;38(3):204-9., [PMID:15274098]

Abstract [show]
In cystic fibrosis (CF), sweat chloride concentration has been proposed as an index of CFTR function for testing systemic drugs designed to activate mutant CFTR. This suggestion arises from the assumption that greater residual CFTR function should lead to a lower sweat chloride concentration, as well as protection against severe lung disease. This logic gives rise to the hypothesis that the lower the sweat chloride concentration, the less severe the lung disease. In order to test this hypothesis, we studied 230 patients homozygous for the DeltaF508 allele, and 34 patients with at least one allele associated with pancreatic sufficiency, born since January 1, 1955, who have pulmonary function data and sweat chloride concentrations recorded in our CF center database, and no culture positive for B. cepacia. We calculated a severity index for pulmonary disease, using an approach which takes into account all available pulmonary function data as well as the patient's current age and survival status. Patients with alleles associated with pancreatic sufficiency had significantly better survival (P = 0.0083), lower sweat chloride concentration (81.4 +/- 23.8 vs. 103.2 +/- 14.2 mEq/l, P < 0.0001), slower rate of decline of FEV(1) % predicted (-0.75 +/- 0.34 vs. -2.34 +/- 0.17% predicted per year), and a better severity index than patients homozygous for the DeltaF508 allele (median 73rd percentile vs. median 55th percentile, P = 0.0004). However, the sweat chloride concentration did not correlate with the severity index, either in the population as a whole, or in the population of patients with alleles associated with pancreatic sufficiency, who are thought to have some residual CFTR function. These data suggest that, by itself, sweat chloride concentration does not necessarily predict a milder pulmonary course in patients with cystic fibrosis.

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26 T (12); A455E (1); D1270N; G85E (3); R117H (4); R334W (1); R347H (1); T347P (6); 2859 þ 5 G ! Login to comment

[hide] Use of fecal elastase-1 to classify pancreatic sta... J Pediatr. 2004 Sep;145(3):322-6. Borowitz D, Baker SS, Duffy L, Baker RD, Fitzpatrick L, Gyamfi J, Jarembek K
Use of fecal elastase-1 to classify pancreatic status in patients with cystic fibrosis.
J Pediatr. 2004 Sep;145(3):322-6., [PMID:15343184]

Abstract [show]
OBJECTIVE: To test the hypothesis that some patients with cystic fibrosis (CF) are misclassified as pancreatic insufficient, using fecal elastase-1 (FE-1) to define pancreatic status. STUDY DESIGN: Subjects with CF at 33 CF centers filled out questionnaires and submitted a stool specimen that was analyzed for FE-1. Subjects taking pancreatic enzyme supplements (PES) were asked to discontinue them and perform a 3-day fecal fat balance study if their FE-1 was >200 microg/g stool and they had never had pancreatitis. RESULTS: The median value for FE-1 in 1215 subjects was 0 microg/g stool (range, 0-867). There was a significant difference between patients who had been prescribed PES (n=1131) and those who had FE-1 <200 microg/g stool (n=1074; P<.0001). Sixty-seven subjects met criteria for discontinuation of PES. The mean coefficient of fat absorption for these subjects was 96.1%. CONCLUSIONS: FE-1 is an accurate, easily obtained screening test to classify pancreatic status in patients with CF. This information is important for prognostication, treatment, and to avoid misclassification in clinical research. Measurement of FE-1 should become a standard of care for patients with CF.

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116 FE-1 values in subjects with CFTR mutations associated with pancreatic sufficiency11 N Mean (mg/g stool) Median (mg/g stool) Range (mg/g stool) Subjects with at least one PS allele* FE-1 >200 mg/g stool 16 584 582.9 349-773 FE-1 <200 mg/g stool 5 64.4 74.8 0-125 Subjects with at least one PS variable alleley FE-1>200 mg/g stool 29 496.2 493.6 224-798 FE-1 <200 mg/g stool 13 76.1 65.9 0-187 *Pancreatic sufficient dominant CF alleles G551S R117H R347H P574H R334W R352Q T3381 yVariable pancreatic sufficient CF mutations G85E 3849 + 10 kb C fi T R347P 2789 + 5G fi A A455E In summary, FE-1 is an accurate, easily obtained screening test to classify patients with CF as PI or PS. Login to comment

[hide] Cystic fibrosis screening: lessons learned from th... Genet Med. 2004 May-Jun;6(3):136-40. Strom CM, Crossley B, Redman JB, Buller A, Quan F, Peng M, McGinnis M, Sun W
Cystic fibrosis screening: lessons learned from the first 320,000 patients.
Genet Med. 2004 May-Jun;6(3):136-40., [PMID:15354331]

Abstract [show]
PURPOSE: To examine the data from > 335,000 Cystic fibrosis (CF) tests to detect unsuspected findings and obtain clinical data when indicated to optimize genetic counseling. METHODS: A proprietary database containing 335,204 consecutive CF DNA tests and 445 CF prenatal diagnostic tests was queried. Clinical information was obtained for prenatal and selected nonprenatal cases by telephone contact with physician offices. RESULTS: The mutation 1078delT was found in much lower frequency than expected with rates of only 1:55,867 tests and 0.06% of CF mutations. This level is below the threshold set by the American College of Medical Genetics. Homozygosity was observed for 2789+5G>A in a 29-year-old women and compound heterozygosity with delta F408 in a 40-year-old woman with isolated chronic sinusitis. Many patients elected prenatal diagnosis when not at a 1:4 risk due to echogenic bowel or IVS-8 5T issues. CONCLUSIONS: With the exception of 1078delT, all CF mutations in the ACMG panel were detected with a frequency of > 0.1% of CF chromosomes. When ACMG guidelines are strictly adhered to, population-based CF carrier screening will accurately identify couples at risk for having children with CF.

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47 Frequency, all tests Frequency, CF mutations (%) delta F508 7610 1:44 75% R117H/7T or 9T 1030 1:325 NAb R117H/5T 103 1:3,254 0.51c W1282X 529 1:625 5.2 G542X 382 1:909 3.8 G551D 278 1:1,250 2.7 N1303K 201 1:1,668 2.0 3849ϩ10kb CϾT 167 1:2,007 1.6 1717-1 GϾA 102 1:3,286 1.0 R553X 102 1:3,286 1.0 621ϩ1 GϾT 98 1:3,420 0.97 2789ϩ5 GϾA 82 1:4,087 0.80 3120ϩ1 GϾA 73 1:4,591 0.72 R1162X 54 1:6,207 0.53 R334W 54 1:6,207 0.53 685E 52 1:6,446 0.51 R560T 52 1:6,446 0.51 Delta I507 51 1:6,572 0.50 711ϩ1 GϾT 40 1:8,380 0.39 1898ϩ1 GϾA 37 1:9,059 0.36 3659 del C 36 1:9,311 0.36 A455E 34 1:9,858 0.33 R347P 33 1:10,158 0.32 2184 del A 14 1:23,943 0.14 1078 del T 6 1:55,867 0.06 a I148T has been eliminated from these data. Login to comment

[hide] Cystic fibrosis population carrier screening: 2004... Genet Med. 2004 Sep-Oct;6(5):387-91. Watson MS, Cutting GR, Desnick RJ, Driscoll DA, Klinger K, Mennuti M, Palomaki GE, Popovich BW, Pratt VM, Rohlfs EM, Strom CM, Richards CS, Witt DR, Grody WW
Cystic fibrosis population carrier screening: 2004 revision of American College of Medical Genetics mutation panel.
Genet Med. 2004 Sep-Oct;6(5):387-91., [PMID:15371902]

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70 It has been ar- Table 1 CFTR mutation frequency among individuals with clinically diagnosed cystic fibrosis by racial/ethnic group and in a pan-ethnic U.S. population CFTR mutation Mutation frequency among individuals with clinically diagnosed cystic fibrosis (%) Non-Hispanic Caucasian Hispanic Caucasian African American Asian American Ashkenazi Jewish Pan-Ethnic Population5 delF508 72.42 54.38 44.07 38.95 31.41 66.31 G542X 2.28 5.10 1.45 0.00 7.55 2.64 W1282X 1.50 0.63 0.24 0.00 45.92 2.20 G551D 2.25 0.56 1.21 3.15 0.22 1.93 621ϩ1GϾT 1.57 0.26 1.11 0.00 0.00 1.30 N1303K 1.27 1.66 0.35 0.76 2.78 1.27 R553X 0.87 2.81 2.32 0.76 0.00 1.21 dell507 0.88 0.68 1.87 0.00 0.22 0.90 3849ϩ10kbCϾT 0.58 1.57 0.17 5.31 4.77 0.85 3120ϩ1GϾT 0.08 0.16 9.57 0.00 0.10 0.86 R117H 0.70 0.11 0.06 0.00 0.00 0.54 1717-1GϾT 0.48 0.27 0.37 0.00 0.67 0.44 2789ϩ5GϾA 0.48 0.16 0.00 0.00 0.10 0.38 R347P 0.45 0.16 0.06 0.00 0.00 0.36 711ϩ1GϾT 0.43 0.23 0.00 0.00 0.10 0.35 R334W 0.14 1.78 0.49 0.00 0.00 0.37 R560T 0.38 0.00 0.17 0.00 0.00 0.30 R1162X 0.23 0.58 0.66 0.00 0.00 0.30 3569delC 0.34 0.13 0.06 0.00 0.00 0.28 A455E 0.34 0.05 0.00 0.00 0.00 0.26 G85E 0.29 0.23 0.12 0.00 0.00 0.26 2184delA 0.17 0.16 0.05 0.00 0.10 0.15 1898ϩ1GϾA 0.16 0.05 0.06 0.00 0.10 0.13 l148T 0.09 0.09 0.05 0.00 0.10 0.08 1078delT 0.02 0.09 0.00 0.00 0.00 0.03 Total 88.40 71.90 64.51 48.93 94.14 84.00 gued that a laboratory is obligated to report any and all information that is gleaned from a test system, however, there is no regulatory requirement and practice varies. Login to comment

[hide] CFTR mutation distribution among U.S. Hispanic and... Genet Med. 2004 Sep-Oct;6(5):392-9. Sugarman EA, Rohlfs EM, Silverman LM, Allitto BA
CFTR mutation distribution among U.S. Hispanic and African American individuals: evaluation in cystic fibrosis patient and carrier screening populations.
Genet Med. 2004 Sep-Oct;6(5):392-9., [PMID:15371903]

Abstract [show]
PURPOSE: We reviewed CFTR mutation distribution among Hispanic and African American individuals referred for CF carrier screening and compared mutation frequencies to those derived from CF patient samples. METHODS: Results from CFTR mutation analyses received from January 2001 through September 2003, were analyzed for four populations: Hispanic individuals with a CF diagnosis (n = 159) or carrier screening indication (n = 15,333) and African American individuals with a CF diagnosis (n = 108) or carrier screening indication (n = 8,973). All samples were tested for the same 87 mutation panel. RESULTS: In the Hispanic population, 42 mutations were identified: 30 in the patient population (77.5% detection rate) and 33 among carrier screening referrals. Five mutations not included in the ACMG/ACOG carrier screening panel (3876delA, W1089X, R1066C, S549N, 1949del84) accounted for 7.55% detection in patients and 5.58% among carriers. Among African American referrals, 33 different mutations were identified: 21 in the patient population (74.4% detection) and 23 in the carrier screening population. Together, A559T and 711+5G>A were observed at a detection rate of 3.71% in CF patients and 6.38% in carriers. The mutation distribution seen in both the carrier screening populations reflected an increased frequency of mutations with variable expression such as D1152H, R117H, and L206W. CONCLUSIONS: A detailed analysis of CFTR mutation distribution in the Hispanic and African American patient and carrier screening populations demonstrates that a diverse group of mutations is most appropriate for diagnostic and carrier screening in these populations. To best serve the increasingly diverse U.S. population, ethnic-specific mutations should be included in mutation panels.

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35 87 mutation panel The following mutations were included in the panel: ⌬F508, ⌬F311, ⌬I507, A455E, A559T, C524X, D1152H, D1270N, E60X, G178R, G330X, G480C, G542X, G551D, G85E, G91R, I148T, K710X, L206W, M1101K, N1303K, P574H, Q1238X, Q359K/T360K, Q493X, Q552X, Q890X, R1066C, R1158X, R1162X, R117C, R117H, R1283M, R334W, R347H, R347P, R352Q, R553X, R560T, S1196X, S1251N, S1255X, S364P, S549I, S549N, S549R, T338I, V520F, W1089X, W1282X, Y1092X, Y563D, 1078delT, 1161delC, 1609delCA, 1677delTA, 1717-1GϾA, 1812-1GϾA, 1898ϩ1GϾA, 1898ϩ5GϾT, 1949del84, 2043delG, 2143delT, 2183delAAϾG, 2184delA, 2307insA, 2789ϩ5GϾA, 2869insG, 3120ϩ1GϾA, 3120GϾA, 3659delC, 3662delA, 3791delC, 3821delT, 3849ϩ10kbCϾT, 3849ϩ4AϾG, 3905insT, 394delTT, 405ϩ1GϾA, 405ϩ3AϾC, 444delA, 574delA, 621ϩ1GϾT, 711ϩ1GϾT, 711ϩ5GϾA, 712-1GϾT, 3876delA CFTR mutation analysis Genomic DNA was extracted from peripheral blood lymphocytes, buccal cell swabs, or bloodspots by Qiagen QIAmp 96 DNA Blood Kit. Specimens were tested for 87 mutations by a pooled allele-specific oligonucleotide (ASO) hybridization method as previously described.16,17 Two multiplex chain reactions (PCR) were used to amplify 19 regions of the CFTR gene. Login to comment

[hide] Clinical sensitivity of prenatal screening for cys... Genet Med. 2004 Sep-Oct;6(5):405-14. Palomaki GE, FitzSimmons SC, Haddow JE
Clinical sensitivity of prenatal screening for cystic fibrosis via CFTR carrier testing in a United States panethnic population.
Genet Med. 2004 Sep-Oct;6(5):405-14., [PMID:15371905]

Abstract [show]
PURPOSE: To estimate CFTR mutation frequencies, clinical sensitivities (proportions of carrier couples or affected fetuses detected), and birth prevalence estimates for broad racial/ethnic groups and for a panethnic U.S. population. METHODS: Published sources of information were identified, corrected when appropriate, and summarized. Combining racial/ethnic-specific mutation frequencies and birth prevalence estimates allowed the computation of panethnic estimates. RESULTS: Two of the 25 recommended mutations do not meet the 0.1% threshold in a panethnic population set by the American College of Medical Genetics. The clinical sensitivities are estimated to be 71.9%, 51.7%, 41.6%, 88.6%, and 23.4% for non-Hispanic Caucasians, Hispanic Caucasian, African American, Ashkenazi Jewish Caucasian, and Asian American couples, respectively. Birth prevalence estimates are 1:2,500, 1:13,500, 1:15,100, 1:2,270, and 1:35,100, whereas the number of couples needed to screen to detect an affected fetus are about 3,200, 26,120; 36,040; 2,600, and 129,600, respectively, for the same racial/ethnic groups. CONCLUSIONS: Overall, the panethnic estimates for CFTR mutation frequencies are similar to those for non-Hispanic Caucasians. However, large differences in both clinical sensitivity and birth prevalence exist between the broad racial/ethnic groups examined. Whether and how the differences in the numbers of couples needed to screen to detect an affected fetus are to be included in prenatal screening for cystic fibrosis needs to be more explicitly addressed.

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32 Data from the International Cystic Fibrosis Consortium were taken from Table 1 of its publication.4 Data from the Cystic Fibrosis Foundation National Patient Registry were taken from the year 1999 and stratified according to whether or not the patient was seen Table 1 CFTR mutation frequencies among Hispanic Caucasians with cystic fibrosis within the recommended minimum testing panel Ordera Mutation Mutation frequency (%) CF Consortiumb CF Foundationc Average Cumulative 1 delF508 45.51 63.25 54.38 54.38 2 G542X 5.11 5.09 5.10 59.48 8 delI507 0.59 5.02 2.81 62.29 22 R334W 2.25 1.31 1.78 64.07 6 N1303K 1.65 1.67 1.66 65.73 10 3849 ϩ 10kbC Ͼ T 1.60 1.53 1.57 67.30 7 R553X 0.63 0.73 0.68 67.98 5 W1282X 0.53 0.73 0.63 68.61 19 R1162X 0.57 0.58 0.58 69.19 3 G551D 0.31 0.80 0.56 69.75 12 1717 - 1G Ͼ T 0.10 0.44 0.27 70.02 4 621 ϩ 1G Ͼ T 0.00 0.51 0.26 70.28 14 711 ϩ 1G Ͼ T 0.10 0.36 0.23 70.51 18 G85E 0.10 0.36 0.23 70.74 11 2789 ϩ 5G Ͼ A 0.10 0.22 0.16 70.90 13 R347P 0.10 0.22 0.16 71.06 20 2184delA 0.10 0.22 0.16 71.22 24 3120 ϩ 1G Ͼ T 0.10 0.22 0.16 71.38 17 3569delC 0.10 0.15 0.13 71.51 9 R117H 0.00 0.22 0.11 71.62 23 I148T 0.10 0.07 0.09 71.71 25 1078delT 0.10 0.07 0.09 71.80 16 A455E 0.10 0.00 0.05 71.85 21 1898 ϩ 1G Ͼ A 0.10 0.00 0.05 71.90 15 R560T 0.00 0.00 0.00 71.90 All 25 59.95 83.77 71.90 a The order is based on that found for non-Hispanic Caucasians.3 b Based on between 178 and 958 chromosomes (International Cystic Fibrosis Genetic Analysis Consortium.4 c Based on 1374 chromosomes from clinically diagnosed persons registered in the Cystic Fibrosis Foundation National Patient Registry. Login to comment
54 Only three mutations were never identified (R560T, A455E, and 1898ϩ1GϾA). Login to comment
80 The larger data- Table 2 CFTR mutation frequencies among African American individuals with cystic fibrosis within the recommended minimum testing panel Ordera Mutation Mutation frequency (%) CF Consortiumb CF Foundationc Average Cumulative 1 delF508 35.50 52.63 44.07 44.07 24 3120 ϩ 1G Ͼ T 12.50 6.64 9.57 53.64 8 delI507 0.74 3.89 2.32 55.96 7 R553X 2.37 1.37 1.87 57.83 2 G542X 1.18 1.72 1.45 59.28 3 G551D 0.59 1.83 1.21 60.49 4 621 ϩ 1G Ͼ T 1.18 1.03 1.11 61.60 19 R1162X 0.74 0.57 0.66 62.26 22 R334W 0.74 0.23 0.49 62.75 12 1717 - 1G Ͼ T 0.74 0.00 0.37 63.12 6 N1303K 0.00 0.69 0.35 63.47 5 W1282X 0.00 0.47 0.24 63.71 10 3849 ϩ 10kbC Ͼ T 0.00 0.34 0.17 63.88 15 R560T 0.00 0.34 0.17 64.05 18 G85E 0.00 0.23 0.12 64.17 9 R117H 0.00 0.11 0.06 64.23 13 R347P 0.00 0.11 0.06 64.29 17 3569delC 0.00 0.11 0.06 64.35 21 1898 ϩ 1G Ͼ A 0.00 0.11 0.06 64.41 20 2184delA 0.10 0.00 0.05 64.46 23 I148T 0.10 0.00 0.05 64.51 11 2789 ϩ 5G Ͼ A 0.00 0.00 0.00 64.51 14 711 ϩ 1G Ͼ T 0.00 0.00 0.00 64.51 16 A455E 0.00 0.00 0.00 64.51 25 1078delT 0.00 0.00 0.00 64.51 All 25 56.46 72.42 64.51 a The order is based on that found for non-Hispanic Caucasians.3 b Based on between 79 and 169 chromosomes reported by the International Cystic Fibrosis Genetic Analysis Consortium.4 c Based on 874 chromosomes from clinically diagnosed persons registered in the Cystic Fibrosis Foundation National Patient Registry. Login to comment
107 An earlier article10 reported that 97% of mutations were identified in 90 chromosomes from Ashkenazi Jewish individ- Table 3 CFTR mutation frequencies among Ashkenazi Jewish Caucasian individuals with cystic fibrosis within the recommended minimum testing panel Ordera Mutation Mutation frequency (%) CF Consortiumb Cumulative 5 W1282X 45.92 45.92 1 delF508 31.41 77.33 2 G542X 7.55 84.88 10 3849 ϩ 10kbC Ͼ T 4.77 89.65 6 N1303K 2.78 92.43 12 1717 - 1G Ͼ T 0.67 93.10 7 R553X 0.22 93.32 3 G551D 0.22 93.54 24 3120 ϩ 1G Ͼ T 0.10 93.64 21 1898 ϩ 1G Ͼ A 0.10 93.74 20 2184delA 0.10 93.84 23 I148T 0.10 93.94 11 2789 ϩ 5G Ͼ A 0.10 94.04 14 711 ϩ 1G Ͼ T 0.10 94.14 8 delI507 0.00 94.14 19 R1162X 0.00 94.14 22 R334W 0.00 94.14 4 621 ϩ 1G Ͼ T 0.00 94.14 15 R560T 0.00 94.14 18 G85E 0.00 94.14 9 R117H 0.00 94.14 13 R347P 0.00 94.14 17 3569delC 0.00 94.14 16 A455E 0.00 94.14 25 1078delT 0.00 94.14 Sum 94.14 a The order is based on that found for non-Hispanic Caucasians.3 b Based on between 57 and 503 chromosomes reported by the International Cystic Fibrosis Genetic Analysis Consortium.4 uals with cystic fibrosis, using a panel of 11 mutations. Login to comment
115 In an- Table 4 CFTR mutation frequencies among Asian American individuals with cystic fibrosis within the recommended minimum testing panel Ordera Mutation Mutation frequency (%) Heim et al.1b CF Foundationc Average Cumulative 1 delF508 18.80 59.09 38.95 38.95 10 3849 ϩ 10kbC Ͼ T 0.00 10.61 5.31 44.26 3 G551D 6.30 0.00 3.15 47.41 6 N1303K 0.00 1.52 0.76 48.17 8 delI507 0.00 1.52 0.76 48.93 2 G542X 0.00 0.00 0.00 48.93 4 621 ϩ 1G Ͼ T 0.00 0.00 0.00 48.93 5 W1282X 0.00 0.00 0.00 48.93 7 R553X 0.00 0.00 0.00 48.93 9 R117H 0.00 0.00 0.00 48.93 11 2789 ϩ 5G Ͼ A 0.00 0.00 0.00 48.93 12 1717 - 1G Ͼ T 0.00 0.00 0.00 48.93 13 R347P 0.00 0.00 0.00 48.93 14 711 ϩ 1G Ͼ T 0.00 0.00 0.00 48.93 15 R560T 0.00 0.00 0.00 48.93 16 A455E 0.00 0.00 0.00 48.93 17 3569delC 0.00 0.00 0.00 48.93 18 G85E 0.00 0.00 0.00 48.93 19 R1162X 0.00 0.00 0.00 48.93 20 2184delA 0.00 0.00 0.00 48.93 21 1898 ϩ 1G Ͼ A 0.00 0.00 0.00 48.93 22 R334W 0.00 0.00 0.00 48.93 23 I148T 0.00 0.00 0.00 48.93 24 3120 ϩ 1G Ͼ T 0.00 0.00 0.00 48.93 25 1078delT 0.00 0.00 0.00 48.93 Sum 25.10 72.74 48.93 a The order is based on that found for non-Hispanic Caucasians.3 b Based on 20 chromosomes. Login to comment
173 For exam- Table 7 Estimated number of carriers of the 25 recommended CFTR mutations by racial/ethnic group and weighted average, representing the panethnic population in the United States for 2002 Order CFTR mutation Number of CFTR Mutation Carriers Panethnic frequency, % Non-Hispanic Caucasian Hispanic Caucasian African American Asian American Ashkenazi Jewish Total 1 delF508 64,779 8,207 4,272 886 796 78,940 66.31 2 G542X 2,039 770 141 0 191 3,141 2.64 5 W1282X 1,342 95 23 0 1,164 2,624 2.20 3 G551D 2,013 85 117 72 6 2,293 1.93 4 621 ϩ 1G Ͼ T 1,404 39 108 0 0 1,551 1.30 6 N1303K 1,136 251 34 17 70 1,508 1.27 7 R553X 778 424 225 17 0 1,444 1.21 8 delI507 787 103 181 0 6 1,077 0.90 10 3849 ϩ 10kbC Ͼ T 519 237 16 121 121 1,014 0.85 24 3120 ϩ 1G Ͼ T 72 24 928 0 3 1,027 0.86 9 R117H 626 17 6 0 0 649 0.55 12 1717 - 1G Ͼ T 429 41 36 0 17 523 0.44 11 2789 ϩ 5G Ͼ A 429 24 0 0 3 456 0.38 13 R347P 403 24 6 0 0 433 0.36 14 711 ϩ 1G Ͼ T 385 35 0 0 3 423 0.36 22 R334W 125 269 47 0 0 441 0.37 15 R560T 340 0 16 0 0 356 0.30 19 R1162X 206 88 64 0 0 358 0.30 17 3569delC 304 20 6 0 0 330 0.28 16 A455E 304 8 0 0 0 312 0.26 18 G85E 259 35 12 0 0 306 0.26 20 2184delA 152 24 5 0 3 184 0.15 21 1898 ϩ 1G Ͼ A 143 8 6 0 3 160 0.13 23 I148T 80 14 5 0 3 102 0.09 25 1078delT 18 14 0 0 0 32 0.03 All 79,072 10,856 6,193 1,113 2,389 99,684 84.00 Bolded numbers indicate mutations that are more likely to be found in a racial/ethnic group other than non-Hispanic Caucasians. Login to comment

[hide] Premarital and prenatal screening for cystic fibro... Genet Med. 2004 Sep-Oct;6(5):415-20. Kornreich R, Ekstein J, Edelmann L, Desnick RJ
Premarital and prenatal screening for cystic fibrosis: experience in the Ashkenazi Jewish population.
Genet Med. 2004 Sep-Oct;6(5):415-20., [PMID:15371906]

Abstract [show]
PURPOSE: Since the early 1990s, Dor Yeshorim (DY) and the Mount Sinai School of Medicine (MSSM) have conducted premarital and prenatal carrier screening for cystic fibrosis (CF) in the Ashkenazi Jewish (AJ) population as part of their genetic testing programs, respectively. Together, over 170,000 screenees have been tested. In this study, we report the CF mutation frequencies in over 110,000 screenees who reportedly were of 100% AJ descent from the DY program and MSSM. In addition, the CF mutation frequencies in a group of > 7,000 screenees for AJ diseases who were of < 100% AJ descent are reported. METHODS: Testing for CF mutations was performed by either PCR and restriction digestion or ASO hybridization analyses at MSSM or sent to various academic and commercial laboratories by DY. RESULTS: The overall (and individual) carrier frequency for the five common AJ mutations, W1282X (0.020), DeltaF508 (0.012), G542X (0.0024), 3849+10kb C>T (0.0020), and N1303K (0.0016), among screenees who were 100% AJ was 1 in 26; when D1152H and the rare 1717-1G>A were included, the overall carrier frequency increased to approximately 1 in 23. In four families with D1152H, five compound heterozygotes for D1152H and W1282X (n = 2), DeltaF508 (1) or 3849+10kb C>T (1) were identified. In contrast, the carrier frequency for screenees reporting < 100% AJ descent was approximately 1 in 30 for the seven mutations. CONCLUSIONS: The carrier frequency for five common CF mutations in a large 100% AJ sample increased from 1 in 26 to 1 in 23 when D1152H was included in the panel. Addition of D1152H to mutation panels when screening the AJ population should be considered because compound heterozygosity is associated with a variable disease phenotype. Further studies to delineate the phenotype of CF patients with this mutation are needed.

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62 The additional mutations that were detected were R117H (n ϭ 7), I148T (6), A455E (2), R334W (2), G551D (1), and R553X (1). Login to comment
86 For example, W1282X was the most prevalent mutation among Ashkenazi Jews, present in 46.4% of AJ carriers, whereas it was present in only 1.5% of non-Hispanic Caucasian CF patients.8 ⌬F508, the most common mutation in non-Hispanic Caucasian CF pa- Table 3 Frequency of CFTR mutations among screenees reporting 100% AJ or Ͻ 100% AJ descent who requested carrier testing for CF and at least one other AJ recessive disease CF mutation % of mutations in carriers reporting 100% AJ descent (n ϭ 45,530-117,145) % of mutations among carriers reporting Ͻ100% AJ descent (n ϭ 7,393) % of Non-Hispanic Caucasian CF patient chromosomes8 (n ϭ 37,263) W1282X 46.4 (n ϭ 117,136) 32.3 1.5 ⌬F508 27.1 (n ϭ 117,145) 35.7 71.5 D1152H 12.0 (n ϭ 44,530) 8.7 0.03 G542X 5.3 (n ϭ 117,140) 6.1 2.3 3849ϩ10kb CϾT 4.8 (n ϭ 117,135) 4.9 0.7 N1303K 3.8 (n ϭ 117,141) 3.0 1.3 1717-1GϾA 0.6 (n ϭ 60,191) 1.9 0.7 R117H a 2.7 0.8 I148T a 2.3 0.05 R334W - 0.76 0.16 A455E - 0.76 0.19 G551D a 0.38 2.5 R553X - 0.38 1.0 a These mutations were detected when screening Ϸ2,300 100% AJ individuals with the ACMG recommended panel. Login to comment

[hide] Use of MALDI-TOF mass spectrometry in a 51-mutatio... Genet Med. 2004 Sep-Oct;6(5):426-30. Buyse IM, McCarthy SE, Lurix P, Pace RP, Vo D, Bartlett GA, Schmitt ES, Ward PA, Oermann C, Eng CM, Roa BB
Use of MALDI-TOF mass spectrometry in a 51-mutation test for cystic fibrosis: evidence that 3199del6 is a disease-causing mutation.
Genet Med. 2004 Sep-Oct;6(5):426-30., [PMID:15371908]

Abstract [show]
PURPOSE: We developed a 51-mutation extended cystic fibrosis (CF) panel that incorporates the 25 previously recommended CFTR mutations, plus 26 additional mutations including 3199del6, which was associated with I148T. METHODS: This assay utilizes an integrated matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry system. RESULTS: CF testing was performed on over 5,000 individuals, including a 3-year-old Hispanic-American patient with a compound heterozygous G542X/3199del6 genotype. He is negative for I148T, or other mutations assessed by CFTR gene sequencing. CONCLUSION: These results demonstrate the successful implementation of MALDI-TOF mass spectrometry in CF clinical testing, and establish 3199del6 as a disease-causing CF mutation.

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77 This assay also demonstrated heterozygosity for the G542X mutation, and reflex testing for the 5T variant at CFTR intron 8 showed a genotype of 7T/9T in this patient (data not Table 3 Description of the 16 multiplex assays designed to analyze 51 CFTR mutations Multiplex Mutations Exon 1 1078delT, G314E, R352Q, G330X 7 2 R347H, R347P, R334W, 1717-1A 7, 11 3 R553X, S549N, R1162X 11, 19 4 A559T, R560T, G551D 11 5 G542X, S549R, 621ϩ1T, Y122X 4, 11 6 W1282X, 3876delA, 3905insT, D1152H 18, 20 7 3849ϩ4G, 3659delC, 1898ϩ1A 12, 19 8 405ϩ1A, 405ϩ3C, 3120A, 3120ϩ1A 3, 16 9 394delTT, E60X, G85E 3 10 A455E, ⌬F508a 9, 10 11 G480C, Q493X, V520F 10 12 711ϩ1T, G178R, 3199del6 5, 17a 13 2143delT, 2184delA, K710X, F316L 7, 13 14 I148T, R117H, R117C 4 15 N1303K, 2789ϩ5A, 3849ϩ10kbT 14b, intron19, 21 16 ⌬I507a 10 17 5Tb intron 8 a F508C and I507V, I506V, I506M variants are tested for concurrently with the ⌬F508 and ⌬I507 assays respectively. Login to comment
93 Two previously unreported missense alleles were identified: G314A (allelic to G314E) and A455V (allelic to A455E). Login to comment

[hide] Cystic fibrosis carrier screening: validation of a... Genet Med. 2004 Sep-Oct;6(5):431-8. Edelmann L, Hashmi G, Song Y, Han Y, Kornreich R, Desnick RJ
Cystic fibrosis carrier screening: validation of a novel method using BeadChip technology.
Genet Med. 2004 Sep-Oct;6(5):431-8., [PMID:15371909]

Abstract [show]
PURPOSE: To validate a novel BeadChip assay system for cystic fibrosis (CF) mutation testing using the panel of 25 ACMG recommended mutations and D1152H. METHODS: DNA from 519 individuals originally tested for CF mutation status by allele specific oligonucleotide hybridization (ASOH) were blindly analyzed by the BeadChip assay and the results were compared. The elongation mediated multiplexed analysis of polymorphisms (eMAP) protocol, which combines multiplex amplification of genomic DNA and multiplex detection of mutations on color-coded bead arrays, was used to analyze 26 CF mutations in two separate groups. RESULTS: The system accurately distinguished the 26 CF genotypes and had 100% concordance with the ASOH technique with an assay failure rate of 1.7%. Benign variants of exon 10 codons 506, 507, and 508 did not interfere with mutation identification and reflex testing for the 5/7/9T IVS8 polymorphism was performed on a separate array. CONCLUSIONS: The BeadChip assay system provided accurate and rapid identification of the ACMG recommended CF mutations.

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35 Mutation controls included DNA from previously identified positive patient samples (I148T, D1152H, W1282X, R117H, G85E, A455E, delF508, N1303K) and DNA from NIGMS Human Genetic Cell Repositories (Coriell Cell Repositories) (delF508, delI507, G542X, R560T, 3849ϩ10kbCϾT, N1303K, G85E; G551D, R553X, 621ϩ1GϾT, 1717-1GϾA, A455E, R334W, R347P, R1162X, 3659delC; 711ϩ1GϾT, 2789ϩ5GϾA, 3120ϩ1GϾA). Login to comment
46 Mutant ASOs were end-labeled with ␥-32 P-ATP and pooled into three subgroups (IA-IC) for Group I and four subgroups (IIA-IID) for Group II mutations with the following breakdown of mutations: IA: delF508, delI507, W1282X, R117H; IB: G542X, R560T, 3849ϩ10kbCϾT, N1303K, G85E; IC: G551D, R553X, 621ϩ1GϾT, 1717-1GϾA, I148T; IIA: A455E, R334W, D1152H; IIB: R347P, 1078delT, R1162X, 3659delC; IIC: 711ϩ1GϾT, 1898ϩ1GϾA, 2789ϩ5GϾA, 3120ϩ1GϾA; IID: 2184delA. Login to comment

[hide] Late diagnosis defines a unique population of long... Am J Respir Crit Care Med. 2005 Mar 15;171(6):621-6. Epub 2004 Dec 10. Rodman DM, Polis JM, Heltshe SL, Sontag MK, Chacon C, Rodman RV, Brayshaw SJ, Huitt GA, Iseman MD, Saavedra MT, Taussig LM, Wagener JS, Accurso FJ, Nick JA
Late diagnosis defines a unique population of long-term survivors of cystic fibrosis.
Am J Respir Crit Care Med. 2005 Mar 15;171(6):621-6. Epub 2004 Dec 10., 2005-03-15 [PMID:15591474]

Abstract [show]
Although the median survival for patients with cystic fibrosis (CF) is 32.9 years, a small group of patients live much longer. We analyzed the genotype and phenotype of CF patients 40 years and older seen between 1992 and 2004 at the National Jewish Medical and Research Center (n = 55). These patients were divided into two groups according to age at diagnosis: an early diagnosis (ED) group, median age at diagnosis 2.0 years (range 0.1-15 years, n = 28), and a late diagnosis (LD) group, median age of diagnosis 48.8 years (range 24-72.8 years, n = 27). Consistent with the hypothesis that the CFTR genotype affects the age at diagnosis, CFTR DeltaF508 homozygous individuals were more common in the ED group. Although patients in the ED group were predominantly male, the majority of LD patients were female. Patients with CF diagnosed late had a significantly lower prevalence of pancreatic insufficiency and CF-related diabetes, and better lung function. Fewer patients in the LD groups were infected with Pseudomonas aeruginosa, whereas a greater percentage had cultures positive for nontuberculous mycobacteria. This is the largest cohort of older patients with CF described to date, and our findings indicate that patients diagnosed as adults differ distinctly from survivors of long-term CF diagnosed as children.

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90 Type III-V mutations, typically A455E and other missense mutations, together with unknown mutations (likely rare missense mutations) were more common in the LD group (solid bar); p Ͻ 0.05 by Fisher`s exact test. LD group, four individuals lacked a ⌬F508 allele, and only one individual was homozygous. Login to comment
117 GENOTYPE DISTRIBUTION Early Diagnosis Late Diagnosis ⌬F508/⌬F508 10 1 ⌬F508/⌬I507 1 ⌬F508/G551D 1 ⌬F508/M1101K 1 ⌬F508/P67L/11027T 1 ⌬F508/3120G-A 1 ⌬F508/2789ϩ5G-A 1 2 ⌬F508/W1282X 1 ⌬F508/621ϩ1G-T 1 ⌬F508/R347P 1 ⌬F508/3849ϩ10kbC-T 1 1 ⌬F508/A455E 2 ⌬F508/R347H 2 ⌬F508/D1152H 1 ⌬508/I148T 1 ⌬F508/R117H 1 ⌬F508/Y109N 1 ⌬F508/IVS8-5T 1 ⌬F508/unknown 3 5 S1251N/D1152H 1 G542X/R117C 1 R117H/G551D 1 W1282X/D1152H 1 Unknown 4 4 Values represent number of individuals in each diagnostic group with each genotype. Login to comment

[hide] Molecular pathology of the CFTR locus in male infe... Reprod Biomed Online. 2005 Jan;10(1):14-41. Claustres M
Molecular pathology of the CFTR locus in male infertility.
Reprod Biomed Online. 2005 Jan;10(1):14-41., [PMID:15705292]

Abstract [show]
Congenital bilateral absence of the vas deferens (CBAVD) is a form of infertility with an autosomal recessive genetic background in otherwise healthy males. CBAVD is caused by cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations on both alleles in approximately 80% of cases. Striking CFTR genotypic differences are observed in cystic fibrosis (CF) and in CBAVD. The 5T allele is a CBAVD mutation with incomplete penetrance. Recent evidence confirmed that a second polymorphic locus exists and is a major CFTR modifier. The development of minigene models have led to results suggesting that CFTR exon 9 is skipped in humans because of unusual suboptimal 5' splice sites. An extremely rare T3 allele has been reported and it has recently been confirmed that the T3 allele dramatically increases exon 9 skipping and should be considered as a 'CF' mutation. Routine testing for the most prevalent mutations in the CF Caucasian population will miss most CFTR gene alterations, which can be detected only through exhaustive scanning of CFTR sequences. Finally, a higher than expected frequency of CFTR mutations and/or polymorphisms is now found in a growing number of monosymptomatic disorders, which creates a dilemma for setting nosologic boundaries between CF and diseases related to CFTR.

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179 2789H-5G-*A. or the 5T allele) or inefficienl trafficking (A455E). Login to comment
466 inducing exon inclusion (Q452P) or exclusion (A455E). Login to comment
472 This is the case of missense A455E, which was found in this study to increase exon 9 skipping {50% in a TGIITO context). Login to comment

[hide] Cystic fibrosis: an overview. J Clin Gastroenterol. 2005 Apr;39(4):307-17. Turcios NL
Cystic fibrosis: an overview.
J Clin Gastroenterol. 2005 Apr;39(4):307-17., [PMID:15758625]

Abstract [show]
Cystic fibrosis (CF) is one of the most common inherited disorders of white populations. The isolation and cloning of the gene in CF that encodes the production of a transport protein that acts as an apical membrane chloride channel, termed cystic fibrosis transmembrane conductance regulator (CFTR), have improved our understanding of the disorder's pathophysiology and has aided diagnosis, but has also revealed the disease's complexity. Gene replacement therapy is still far from being used in patients with CF, mostly because of difficulties in targeting the appropriate cells. Life expectancy of patients with this disorder has greatly improved over past decades because of better symptomatic treatment strategies. This article summarizes advances in understanding and treatment of CF.

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56 T R334W A455E R347H 2789 5G ! Login to comment

[hide] Pancreatitis among patients with cystic fibrosis: ... Pediatrics. 2005 Apr;115(4):e463-9. Epub 2005 Mar 16. De Boeck K, Weren M, Proesmans M, Kerem E
Pancreatitis among patients with cystic fibrosis: correlation with pancreatic status and genotype.
Pediatrics. 2005 Apr;115(4):e463-9. Epub 2005 Mar 16., [PMID:15772171]

Abstract [show]
OBJECTIVE: Pancreatitis is an infrequent complication among patients with cystic fibrosis (CF). It has mainly been reported for patients with pancreatic sufficiency (PS). Previous studies involved only a small number of patients because they contained data from single centers. The aim of this study was to evaluate the incidence of pancreatitis in a large heterogeneous CF population, to determine the relationship with pancreatic function, and to assess whether pancreatitis is associated with specific CFTR mutations. METHODS: Physicians caring for patients with CF were approached through the CF Thematic Network or through the European Cystic Fibrosis Foundation newsletter. They were asked to provide data on their current patient cohort through a standardized questionnaire and to report how many patients they had ever diagnosed as having pancreatitis. A detailed questionnaire was then sent, to be filled out for all of their patients for whom pancreatitis had ever occurred. We defined pancreatitis as an episode of acute abdominal pain associated with serum amylase levels elevated above the ranges established by each participating center's laboratory. General clinical data included age, genotype, age at diagnosis of CF, sweat chloride concentrations, pancreatic status, biometric findings, and respiratory status. CFTR mutations were also reported according to the functional classification of classes I to V. Patients were categorized as having PS, pancreatic insufficiency (PI), or PI after an initial period of PS. PI was defined as a 72-hour stool fat loss of >7 g/day, fat absorption of <93%, or fecal elastase levels of <200 microg/g feces. Clinical data on pancreatitis included age at the first episode, amylase and lipase levels, possible triggers, and occurrence of relapses or complications. RESULTS: A total of 10071 patients with CF, from 29 different countries, who were undergoing follow-up monitoring in 2002 were surveyed. Among this group, pancreatitis had ever been diagnosed for 125 patients (1.24%; 95% confidence interval [CI]: 1.02-1.46%). There was variability in the reported rates of pancreatitis for different countries. Twenty-six centers in 15 different countries sent detailed clinical data on their patients with pancreatitis and on their whole CF clinic. This involved 3306 patients with CF and 61 cases of pancreatitis, leading to a prevalence of 1.84% (95% CI: 1.39-2.30%). The mean age of the patients with pancreatitis ever was 24.4 years (SD: 10.8 years). The first episode of pancreatitis occurred at a mean age of 19.9 years (SD: 9.6 years). The median serum amylase level at the time of pancreatitis was 746 IU/L (interquartile range: 319-1630 IU/L), and the median lipase level was 577 IU/L (interquartile range: 229-1650 IU/L). The majority of patients had PS (34 of 61 patients, 56%; 95% CI: 43-68%). Pancreatitis occurred for 15 patients with PI (25%; 95% CI: 14-35%). Eight patients developed PI after initial PS. The occurrence of pancreatitis among patients with PS was 34 cases per 331 patients, ie, 10.27% (95% CI: 7.00-13.55%); the occurrence of pancreatitis among patients with PI was 15 cases per 2971 patients, ie, 0.5% (95% CI: 0.25-0.76%). The mean age (in 2002) of the CF cohort with pancreatitis did not differ between the PS and PI subgroups. The forced expiratory volume in 1 second was significantly lower among the patients with PI than among the patients with PS, ie, 65% (SEM: 7%) vs 79% (SEM: 4%). The mean age at the occurrence of pancreatitis and the amylase and lipase levels during pancreatitis were not different for patients with pancreatitis and PI versus PS. In the group with PS, 31 of 34 patients carried at least 1 class IV or V CFTR mutation. In the groups with PI and PI after PS, 5 of 15 patients and 3 of 8 patients, respectively, carried 2 class I, II, or III CFTR mutations. Relapses and/or evolution to chronic pancreatitis occurred for 42 patients. Pancreatitis preceded the diagnosis of CF in 18 of 61 cases. These patients were significantly older than the rest of the cohort, ie, age of 28.4 years (SEM: 3.4 years) vs 22.7 years (SEM: 1.3 years). Their median age at the diagnosis of CF was also significantly greater, ie, 21.5 years (interquartile range: 11.9-31 years) vs 7.6 years (interquartile range: 0.4-17.0 years). However, the ages at the occurrence of pancreatitis were similar, ie, 21.0 years (SEM: 3.0 years) vs 19.5 years (SEM: 1.2 years). CONCLUSIONS: This study of 10071 patients with CF from 29 different countries revealed an estimated overall occurrence of pancreatitis among patients with CF of 1.24% (95% CI: 1.02-1.46%). The incidence of pancreatitis was much higher among patients with PS. However, pancreatitis was also reported for 15 patients with PI from 11 centers in 9 different countries. A correct diagnosis of pancreatitis for the reported patients with PI was supported by amylase and lipase levels increased above 500 IU/L, similar to those for patients with PS and pancreatitis. A correct diagnosis of PI for these patients with pancreatitis was supported by the adequacy of the methods used. We chose the cutoff values used to distinguish between patients with PI and control subjects without gastrointestinal disease. For one half of the patients, the diagnosis of PI was established on the basis of low levels of stool elastase (mean: 97 mug/g stool). With a cutoff value of 200 microg/g stool, this noninvasive test has high sensitivity (>95%) and high specificity (>90%) to differentiate patients with PI from control subjects with normal pancreatic function. For the other one half of the patients with PI in the cohort, the pancreatic status was determined on the basis of the 3-day fecal fat balance, with the widely used cutoff value of >7 g of fat loss per day. The most likely reason for pancreatitis occurring among patients with PI is that some residual pancreatic tissue is present among these patients. Pancreatitis is a rare complication among patients with CF. It occurred for 1.24% (95% CI: 1.02-1.46%) of a large CF cohort. Pancreatitis occurs mainly during adolescence and young adulthood. It is much more common among patients with CF and PS (10.3%), but it can occur among patients with PI (0.5%). Pancreatitis can be the first manifestation of CF. Pancreatitis was reported for patients carrying a wide range of mutations.

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136 Class IV and V mutations reported among the patients with PI included D1152H (n ϭ 2), A455E (n ϭ 2), R1066H (n ϭ 1), S13F (n ϭ 1), and 1898ϩ3AϾG (n ϭ 1). Login to comment
178 Two patients carried A455E/F508 and 2 carried A455E/621ϩ1GϾT. Munck27 reported acute pancreatitis as a presenting symptom during heat stroke for 3 patients with CF; 1 patient had PS and a fecal elastase level of 500 ␮g/g feces, and the others had moderate PI and stool elastase levels of 102 and 162 ␮g/g. Login to comment
188 A455E, the Dutch mutation, is considered a class IV mutation but 50% to 75% of patients were reported to have PI.26 G85E, the Mediterranean mutation, was reported by Durno et al13 with PS, but it is actually a class II mutation with some variability in pancreatic function.28 In the present study, well-accepted methods of stool analysis (fat loss of Ͼ7 g/day or elastase levels of Ͻ200 ␮g/g stool) were chosen to determine pancreatic status as PS or PI. Login to comment

[hide] Frequency and phenotypic consequences of the 3199d... Genet Med. 2005 Mar;7(3):210-1. Ruchon AF, Ryan SR, Fetni R, Rozen R, Scott P
Frequency and phenotypic consequences of the 3199del6 CFTR mutation in French Canadians.
Genet Med. 2005 Mar;7(3):210-1., [PMID:15775760]

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67 A pancreatic sufficiency phenotype was found in two patients carrying A455E on the second allele, consistent with the previously reported association of A455E with a mild CF phenotype.6 In two patients, a second CF-causing mutation was not identified despite the use of a 35 mutation panel, which included the 25 ACMG recommended mutations. Login to comment
88 Phenotype correlation in cystic fibrosis patients compound heterozygous for the A455E mutation. Login to comment

[hide] Lack of association of common cystic fibrosis tran... Am J Gastroenterol. 2005 Apr;100(4):874-8. Gallegos-Orozco JF, E Yurk C, Wang N, Rakela J, Charlton MR, Cutting GR, Balan V
Lack of association of common cystic fibrosis transmembrane conductance regulator gene mutations with primary sclerosing cholangitis.
Am J Gastroenterol. 2005 Apr;100(4):874-8., [PMID:15784035]

Abstract [show]
BACKGROUND: Primary sclerosing cholangitis (PSC) is a chronic progressive cholestatic liver disease of uncertain etiology. However, the histologic features of PSC liver disease can resemble those in cystic fibrosis (CF), an inherited disorder caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. We sought to determine if PSC patients have a higher frequency of common CF alleles than disease controls. METHODS: DNA was extracted from peripheral lymphocytes of patients with end-stage liver disease. Samples were obtained before liver transplantation from 59 PSC patients and from three groups of control patients (20 each with primary biliary cirrhosis, autoimmune hepatitis, or hepatitis C). DNA samples were genotyped for 32 common CF mutations, the intron 8 T tract variants, and the M470V variant. RESULTS: One of 59 PSC patients (1.7%) had the common CF mutation (DeltaF508) in one CFTR gene. Two controls (3.3%) carried a single CF mutation (DeltaF508 in one primary biliary cirrhosis patient; W1282X in one hepatitis C patient). These rates do not differ from expected in the general population. The frequency of CFTR variants (5T and M470V) was also similar between PSC patients and controls. CONCLUSIONS: Despite anatomical similarities between CF liver disease and PSC, we could not confirm that PSC patients carried common CF mutations or common CFTR variants in higher than expected frequencies. These data suggest that CFTR dysfunction does not influence the pathogenesis of PSC.

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55 CFTR Mutations and Associated Phenotype Classic Nonclassic Cystic Fibrosis Cystic Fibrosis Variant Normal 621 + 1G→T R117H G85E* 7T 711 + 1G→T R334W 5T† 9T 1078delT R347P M470V‡ F508C I507 A455E I507V F508 2789 + 5G → A I506V 1717 - 1G→A 3849 + 10kbC→T G542X G551D R553X R560T R1162X 3659delC W1282X N1303K * Classic cystic fibrosis and nonclassic cystic fibrosis. Login to comment

[hide] Cystic fibrosis prenatal screening in genetic coun... J Genet Couns. 2005 Feb;14(1):1-15. Langfelder-Schwind E, Kloza E, Sugarman E, Pettersen B, Brown T, Jensen K, Marcus S, Redman J
Cystic fibrosis prenatal screening in genetic counseling practice: recommendations of the National Society of Genetic Counselors.
J Genet Couns. 2005 Feb;14(1):1-15., [PMID:15789152]

Abstract [show]
For over a decade, prenatal screening for cystic fibrosis (CF) has been considered a model for the integration of genetic testing into routine medical practice. Data from pilot studies and public policy discourse have led to recommendations by some professional organizations that CF screening should be offered or made available to pregnant women and their partners, and to couples planning a pregnancy. It is crucial that genetic counselors gain thorough understanding of the complexities of CF and the implications of positive test results, so that they may serve as a reliable, educated referral base and resource for health care providers and their patients. While not all pregnant women will be referred for genetic counseling prior to CF carrier testing, genetic counselors often will be asked to counsel clients after they have a positive test result, or who are found to be at increased risk. Genetic counselors can play an important role in providing accurate and current information as well as support for patients' informed decisions. These recommendations were created by a multicenter working group of genetic counselors with expertise in CF and are based on personal clinical experience, review of pertinent English language medical articles, and reports of expert committees. The recommendations should not be construed as dictating an exclusive course of management, nor does the use of such recommendations guarantee a particular outcome. These recommendations do not displace a health care provider's professional judgment based on the clinical circumstances of a particular client.

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156 Mutations described as "mild", for example, R117H, R334W, R347P, and A455E (Kristidis et al., 1992; The CF genotype-phenotype consortium, 1993), are more likely to be associated with pancreatic sufficiency regardless of the class of the second mutation. Login to comment

[hide] Cystic fibrosis lung disease: genetic influences, ... Pediatr Radiol. 2005 Aug;35(8):739-57. Epub 2005 May 3. Moskowitz SM, Gibson RL, Effmann EL
Cystic fibrosis lung disease: genetic influences, microbial interactions, and radiological assessment.
Pediatr Radiol. 2005 Aug;35(8):739-57. Epub 2005 May 3., [PMID:15868140]

Abstract [show]
Cystic fibrosis (CF) is a multiorgan disease caused by mutation of the CF transmembrane conductance regulator (CFTR) gene. Obstructive lung disease is the predominant cause of morbidity and mortality; thus, most efforts to improve outcomes are directed toward slowing or halting lung-disease progression. Current therapies, such as mucolytics, airway clearance techniques, bronchodilators, and antibiotics, aim to suppress airway inflammation and the processes that stimulate it, namely, retention and infection of mucus plaques at the airway surface. New approaches to therapy that aim to ameliorate specific CFTR mutations or mutational classes by restoring normal expression or function are being investigated. Because of its sensitivity in detecting changes associated with early airway obstruction and regional lung disease, high-resolution CT (HRCT) complements pulmonary function testing in defining disease natural history and measuring response to both conventional and experimental therapies. In this review, perspectives on the genetics and microbiology of CF provide a context for understanding the increasing importance of HRCT and other imaging techniques in assessing CF therapies.

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71 Modifier genes as modulators of CF lung phenotype Some DF508 homozygous individuals develop severe obstructive lung disease during the first and second decades of life despite maximal medical therapy, while others with the same genotype have little or no obstructive lung disease despite minimal therapy during Table 2 Examples of disease-associated CFTR alleles CFTR allele Allele class Usual clinical status (when compounded with a severe CFTR allelea ) Allele frequency in Caucasiansb General populationc CF CAVD G542X (9T) 1 Pancreatic-insufficient CF 0.001 0.023 0.003 DF508 (9T) 2 Pancreatic-insufficient CF 0.012-0.016 0.694 0.20 G551D (7T) 3 Pancreatic-insufficient CF 0.001 0.022 0.01 R117H (5T) 4 Pancreatic-sufficient CF 0.0001 0.004 ND R117H (7T) 4 CAVD or carrier 0.002-0.003 0.003 0.04 A455E (9T) 5 Pancreatic-sufficient CF ND 0.001 ND 3849+10kbC fi T 5 Pancreatic-sufficient CF ND 0.007 ND WT (5T) 5 CAVD or carrier 0.042 d 0.19 Other allelese 1-5 Variable 0.002-0.006 0.247 0.55 WT (7T or 9T) Wild-type Carrier 0.935 e e a Severe CFTR allele is defined as a class 1, 2, or 3 allele. Login to comment

[hide] Screening of mutations in the CFTR gene in 1195 co... Eur J Hum Genet. 2005 Aug;13(8):959-64. Stuppia L, Antonucci I, Binni F, Brandi A, Grifone N, Colosimo A, De Santo M, Gatta V, Gelli G, Guida V, Majore S, Calabrese G, Palka C, Ravani A, Rinaldi R, Tiboni GM, Ballone E, Venturoli A, Ferlini A, Torrente I, Grammatico P, Calzolari E, Dallapiccola B
Screening of mutations in the CFTR gene in 1195 couples entering assisted reproduction technique programs.
Eur J Hum Genet. 2005 Aug;13(8):959-64., [PMID:15870824]

Abstract [show]
Genetic testing of the cystic fibrosis transmembrane conductance (CFTR) gene is currently performed in couples undergoing assisted reproduction techniques (ART), because of the high prevalence of healthy carriers in the population and the pathogenic relationship with congenital bilateral absence of vas deferens (CBAVD). However, discordant data have been reported concerning the usefulness of this genetic test in couples with no family history of cystic fibrosis (CF). In this study, we report the results of CFTR molecular screening in 1195 couples entering ART. Genetic testing was initially carried out in a single partner of each couple. CFTR mutations were detected in 55 subjects (4.6%), a percentage that overlaps with the one reported in the general population. However, significantly higher frequencies of were found in CBAVD individuals (37.5%) and in males with nonobstructive azoospermia (6.6%). The 5T allele was found in 78 patients (6.5%). This figure was again significantly different in males with nonobstructive-azoospermia (9.9%) and in those with CBAVD (100%). All together, 139 subjects (11.6%) had either a CFTR mutation or the 5T allele. Subsequent molecular analysis of their partners disclosed a CFTR mutation or 5T allele in nine cases (6.5%). However, none of these couples had CFTR alterations in both members, a CFTR mutation being invariably present in one partner and the 5T allele in the other. In order to improve genetic counselling of these couples, the TG-M470V-5T association was analyzed, and a statistically significant relationship between 12TG-V470 and CBAVD was detected.

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64 of detected carriers Prevalence among detected CFTR mutations DF508 40 (3.34%) 65.58% DI507 0 0 G542X 6 (0.50%) 9.84% 1717-1G-A 1 (0.08%) 1.64% G551D 0 0 R553X 0 0 R560T 0 0 Q552X 0 0 W1282X 7 (0.58 %) 11.48% S1251N 0 0 N1303K 3 (0.20%) 4.91% 394delTT 0 0 G85E 3 (0.25%) 4.91% E60X 0 0 621+1G-T 0 0 R117H 0 0 1078delT 0 0 R347P 0 0 R334W 0 0 2143delT 0 0 2183AA-G 0 0 2184delA 0 0 711+5G-A 0 0 2789+5G-A 1 (0.08%) 1.64% R1162X 0 0 3659del5 0 0 3849+10kbC-T 0 0 A455E 0 0 5T 78 (6.52%) Table 2 Distribution of CFTR mutations and 5T allele according to phenotype for the 1195 individuals Phenotype CF/WT 5T/WT CF/5T WT/WT Infertile males (non-CBAVD), N ¼ 304 20 (6.58%) 30 (9.87%) 0 254 (83.55%) Infertile males (CBAVD), N ¼ 16 0 10 (62.50%) 6 (37.50 %) 0 Infertile females, N ¼ 93 5 (5.37%) 7 (7.53%) 0 81 (87.10%) Unexplained infertility, N ¼ 782 30 (3.84%) 31 (3.96%) 0 721 (92.20%) Total ¼ 1195 55 (4.60%) 78 (5.50%) 6 (0.50%) 1056 (88.40%) CFTR alteration was detected, including a mutation in three cases and the 5T polymorphism in the remaining six. Login to comment

[hide] Cystic fibrosis. N Engl J Med. 2005 May 12;352(19):1992-2001. Rowe SM, Miller S, Sorscher EJ
Cystic fibrosis.
N Engl J Med. 2005 May 12;352(19):1992-2001., 2005-05-12 [PMID:15888700]

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124 The A455E mutation (class IV) exhibits onlypartialCFTRion-channelactivity,afeaturethat probably explains a less severe pulmonary phenotype.47 Other mutation classes include reduced numbers of CFTR transcripts (class V) and defective CFTR stability at the cell surface (class VI).48-50 Insight into the cellular consequences of defective CFTR suggests a role for tailored therapies, a predominant theme in clinical research on cystic fibrosis. Login to comment

[hide] Multiple mutation analysis of the cystic fibrosis ... Mol Hum Reprod. 2005 Jun;11(6):463-8. Epub 2005 May 20. Sanchez-Garcia JF, Benet J, Gutierrez-Mateo C, Luis Seculi J, Monros E, Navarro J
Multiple mutation analysis of the cystic fibrosis gene in single cells.
Mol Hum Reprod. 2005 Jun;11(6):463-8. Epub 2005 May 20., [PMID:15908456]

Abstract [show]
PGD is becoming an alternative to prenatal diagnosis. The combination of IVF techniques with the PCR technology allows for the detection of genetic abnormalities in first polar bodies from oocytes and blastomeres from cleavage-stage embryos. Dealing with a genetic disease with a heterogeneous spectrum of mutations like cystic fibrosis, one of the objectives of centres offering PGD is the application of simple and efficient protocols that allow for the detection of a wide range of mutations with a single procedure. In the present work, 29 normal loci and the 31 most frequent cystic fibrosis transmembrane conductance regulator (CFTR) mutations in Southern Europe could be detected at the same time in single cells applying a modified and improved primer extension preamplification-PCR. Two different Taq polymerases were tested in isolated buccal cells heterozygous for several mutations. The protocol that gave statistically significant better results was also successful in oocytes and their first polar bodies.

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62 G, R1162X, 3659delC, W1282X, 3905insT, N1303K, 1078delT, R347P, R347H and R334W labelled with TET (green) and A455E, 1898þ1G.A, 2183AA.G, 2789þ5G.A, G85E, 621þ1G.T, R117H, Y122X and 711þ1G.T labelled with HEX (yellow). Login to comment

[hide] Mutation spectrum in Jewish cystic fibrosis patien... Am J Med Genet A. 2005 Jul 30;136(3):246-8. Quint A, Lerer I, Sagi M, Abeliovich D
Mutation spectrum in Jewish cystic fibrosis patients in Israel: implication to carrier screening.
Am J Med Genet A. 2005 Jul 30;136(3):246-8., 2005-07-30 [PMID:15948195]

Abstract [show]
We have tested 144 unrelated Jewish patients suffering from the classical form of cystic fibrosis. The patients were screened for a panel of 12 mutations including the six Ashkenazi founder mutations (DeltaF508, W1282X, N1303K, G542X, 3849 + 10 kb C-->T, 1717-1G > A) and six mutations that were found in non-Ashkenazi Jewish patients (S549R (T-->G), G85E, 405 + 1G-->A, W1089X, Y1092, and D1152H). Patients of Georgian origin were tested also for the Q359K/T360K mutation. In addition, all the patients were tested for the IVS-8 variant (9T/7T/5T). Of all the cystic fibrosis (CF)-bearing chromosomes, 94% (264/281) were accounted for by one of the known mutations, and none of the patients had the 5T allele of the IVS-8 variant. Single strand conformation polymorphism (SSCP) analysis of the coding sequence of the CFTR gene followed by sequencing showed eight mutations on ten CF chromosomes, leaving seven chromosomes (2.5%) with unknown mutations. We identified three mutations in two or more CF chromosomes, 2571 + 1insT in Jews from Iraq, 3121-1G > A in patients from Kurdistan and I1234V in Yemenite Jewish patients. The other five mutations appeared on a single allele and are considered "private mutations." In this study we have identified 99% of CF alleles in Ashkenazi Jewish patients, 91% in Jews of North African origin and 75% in Jewish patients from Iraq. The significance of these findings to the population screening in Israel is discussed.

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37 In this group we revealed two additional mutations L165S and A455E, each was identified on a single chromosome and one mutation remained unidentified. The relative frequencies of the Ashkenazi founder mutations in Ashkenazi patients were W1282X (43%), DF508 (33%), G542X (10%), 3849 þ 10 kb C!T (5%), N1303K (5%), and 1717 (1%). Login to comment
58 Mutations in the CF Bearing Alleles in the Jewish Patients According to the Ethnic Origin Country of origin Ashkenazi Morocco Tunisia Balkan Iraq Iran/ Kurdistan Georgia Yemen Total Number of alleles (%) 193 (69.0) 34 (12.1) 12 (4.3) 21 (7.5) 8 (2.8) 3 (0.7) 8 (2.8) 2 (0.7) 281 W1282X (%) 83 (42.8) 1 (8.3) 4 (19.0) 88 (31.3) DF508 (%) 65 (33.5) 24 (70.6) 3 (25.0) 7 (33.3) 1 100 (35.6) N1303K (%) 10 (5.2) 10 (3.6) G542X (%) 19 (10.3) 4 (19.0) 24 (8.5) 3849-10 kbC!T (%) 10 (5.1) 1 (2.9) 2 (9.5) 13 (4.6) 1717-1G!A (%) 2 (1.0) 2 (0.7) D1152H (%) 1 (0.5) 1 (0.4) S549R (T!G) (%) 4 (11.8) 4 (1.4) G85E (%) 2 (9.5) 2 (0.7) 405 þ 1G!A (%) 8 (66.7) 8 (2.8) Y1092X (%) 3 (37.5) 3 (1.1) W1089X (%) 2 (9.5) 2 (0.7) Q359K/T360K (%) 8 (100) 8 (2.8) I1234V (%) 2 (100) 2 (0.7) 2751 þ 1insT (%) 2 (25.0) 2 (0.7) 3121-1G > A (%) 1 1 (0.4) M952I (%) 1 (12.5) 1 (0.4) L165S (%) 1 (0.5) 1 (0.4) A455E (%) 1 (0.5) 1 (0.4) L997F (%) 1 (2.9) 1 (0.4) G1244E (%) 1 (2.9) 1 (0.4) Unkown (%) 1 (0.5) 3 (8.8) 2 (25.0) 1 7 (2.5) Mutation Spectrum in Jewish CF Patients [Wahab, 2003]. Login to comment

[hide] Genotype-phenotype correlation for pulmonary funct... Thorax. 2005 Jul;60(7):558-63. de Gracia J, Mata F, Alvarez A, Casals T, Gatner S, Vendrell M, de la Rosa D, Guarner L, Hermosilla E
Genotype-phenotype correlation for pulmonary function in cystic fibrosis.
Thorax. 2005 Jul;60(7):558-63., [PMID:15994263]

Abstract [show]
BACKGROUND: Since the CFTR gene was cloned, more than 1000 mutations have been identified. To date, a clear relationship has not been established between genotype and the progression of lung damage. A study was undertaken of the relationship between genotype, progression of lung disease, and survival in adult patients with cystic fibrosis (CF). METHODS: A prospective cohort of adult patients with CF and two CFTR mutations followed up in an adult cystic fibrosis unit was analysed. Patients were classified according to functional effects of classes of CFTR mutations and were grouped based on the CFTR molecular position on the epithelial cell surface (I-II/I-II, I-II/III-V). Spirometric values, progression of lung disease, probability of survival, and clinical characteristics were analysed between groups. RESULTS: Seventy four patients were included in the study. Patients with genotype I-II/I-II had significantly lower current spirometric values (p < 0.001), greater loss of pulmonary function (p < 0.04), a higher proportion of end-stage lung disease (p < 0.001), a higher risk of suffering from moderate to severe lung disease (odds ratio 7.12 (95% CI 1.3 to 40.5)) and a lower probability of survival than patients with genotype I-II/III, I-II/IV and I-II/V (p < 0.001). CONCLUSIONS: The presence of class I or II mutations on both chromosomes is associated with worse respiratory disease and a lower probability of survival.

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185 Although there are a few rare mutations such as A455E and R117H which are clearly linked to a better pulmonary outcome,12 13 the effect on the lungs of F508del and most other mutations cannot be separated and attempts to link mutations in CFTR to severity of lung disease have been unsuccessful.14 Furthermore, genes other than CFTR and environmental factors such as access to specialised centres and treatment strategies may be more important factors in modifying the development, progression, and severity of pulmonary disease. Login to comment
251 The mild pulmonary phenotype seen in patients with genotype I-II/III-V is consistent with previous reports where a few rare mutations such as A455E, R117H, 3849+10kbCRT, 2789+5GRT, and P67L (all class IV or V mutations) are clearly linked to a better pulmonary outcome.13 14 26-28 The findings observed in this study support the hypothesis that differences in CF pulmonary phenotype could be related to the effect of the genotype on CFTR protein production and function. Nevertheless, it is important to recognise that specific mutations may have characteristics of more than one 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 20 30 40 50 60 Follow up (years) Events Lung transplant Dead I-II/I-II 9 6 I-II/III-V 1 0 Genotype I-II/III, IV or V I-II/I-II p<0.001 (Log-rank test for trend) Figure 3 Kaplan-Meier survival curves by genotype. Login to comment

[hide] Genetics of cystic fibrosis. Semin Respir Crit Care Med. 2003 Dec;24(6):629-38. Gallati S
Genetics of cystic fibrosis.
Semin Respir Crit Care Med. 2003 Dec;24(6):629-38., [PMID:16088579]

Abstract [show]
Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, which encodes a protein expressed in the apical membrane of exocrine epithelial cells. CFTR functions principally as a cyclic adenosine monophosphate (cAMP)-induced chloride channel and appears capable of regulating other ion channels. Mutations affect CFTR through a variety of molecular mechanisms, which can produce little or no functional gene product at the apical membrane. More than 1000 different disease-causing mutations within the CFTR gene have been described. The potential of a mutation to contribute to the phenotype depends on its type, localization in the gene, and the molecular mechanism as well as on interactions with secondary modifying factors. Genetic testing can confirm a clinical diagnosis of CF and can be used for infants with meconium ileus, for carrier detection in individuals with positive family history and partners of proven CF carriers, and for prenatal diagnostic testing if both parents are carriers. Studies of clinical phenotype in correlation with CFTR genotype have revealed a very complex relationship demonstrating that some phenotypic features are closely determined by the underlying mutations, whereas others are modulated by modifier genes, epigenetic mechanisms, and environment.

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43 Mutations (missense, nonsense, frameshift, splice, small and large in-frame deletions or insertions) con- Table 1 Distribution of theWorldwide 24 Most Common Cystic Fibrosis Mutationsa Exon/ Northern Southern North South Austral- Relative Mutation Intron Europe Europe America America asia Africa Asia Frequency G85E E 03 30 14 16 n.a. n.a. 0 7 0.15 R117H E 04 62 3 61 n.a. 7 0 0 0.30 621+1G→T I 04 97 37 154 n.a. 27 0 0 0.72 711+1G→T I 05 15 13 21 n.a. n.a. n.a. 0 0.11 1078delT E 07 53 2 1 n.a. 1 n.a. 0 0.13 R334W E 07 18 21 12 n.a. 2 0 0 0.12 R347P E 07 55 24 26 n.a. 1 0 0 0.24 A455E E 09 35 0 27 n.a. n.a. n.a. 0 0.14 ⌬I507 E 10 57 5 20 2 9 0 0 0.21 ⌬F508 E 10 14,866 4007 6901 342 2309 351 173 66.02 1717-1G→A I 10 160 65 44 n.a. 12 0 3 0.65 G542X E 11 439 259 234 38 56 9 27 2.42 S549N E 11 18 2 5 1 3 1 0 0.07 G551D E 11 356 37 206 1 117 0 0 1.64 R553X E 11 165 44 96 5 11 1 0 0.73 R560T E 11 40 0 24 0 3 0 0 0.15 1898+1G→A I 12 41 10 2 n.a. n.a. n.a. 0 0.12 2184delA E 13 14 7 8 n.a. n.a. n.a. 0 0.07 2789+5G→A I 14b 27 10 17 n.a. n.a. n.a. 0 0.12 R1162X E 19 36 68 19 0 2 0 0 0.28 3659delC E 19 39 1 14 n.a. n.a. n.a. 0 0.12 3849+10kbC→T I 19 23 8 57 n.a. n.a. n.a. 16 0.24 W1282X E 20 120 43 245 n.a. 6 2 120 1.22 N1303K E 21 209 179 130 11 23 8 29 1.34 Chromosomes 21,154 7281 10438 758 3095 515 608 screened Detection rate 80.2 66.7 79.9 52.8 83.7 72.2 61.7 aAccording to the Cystic Fibrosis Genetic Analysis Consortium, http://www.genet.sickkids.on.ca/cftr/. Login to comment
59 ClassV: Reduced Synthesis and/orTrafficking Various mutations are associated with reduced biosynthesis of fully active CFTR due to partially aberrant splicing (3849+10kbC→T, T5),21,22 promotor mutations or inefficient trafficking (A455E).23 These mutations result in reduced amounts of functional gene products and thus in milder CF phenotypes. Login to comment
67 SSCP analysis is one of the most popular methods for the detection of sequence variants in polymerase chain reaction (PCR) amplified DNA fragments.29 The princi- Table 3 Cystic Fibrosis Mutations Detected by Commercial Kits INNO-LiPA Mutations CF2 ⌬F508, ⌬I507, G542X, 1717-1G→A, G551D, R553X, W1282X, N1303K CFTR12 ⌬F508, ⌬I507, G542X, 1717-1G→A, G551D, R553X, W1282X, N1303K, S1251N, R560T, 3905insT, Q552X CFTR17+Tn 394delTT, G85E, 621+1G→T, R117H, 1078delT, R347P, R334W, E60X, 2183AA→G, 2184delA, 711+5G→A, 2789+5G→A, R1162X, 3659delC, 3849+10kbC→T, 2143delT, A455E, (5T/7T/9T) Elucigene CF4 ⌬F508, G542X, G551D, 621+1G→T CF12 ⌬F508, G542X, G551D, N1303K, W1282X, 1717-1G→A, R553X, 621+1G→T, R117H, R1162X, 3849+10kbC→T, R334W CF20 1717-1G→A, G542X, W1282X, N1303K, ⌬F508, 3849+10kbC→T, 621+1G→T, R553X, G551D, R117H, R1162X, R334W, A455E, 2183AA→G, 3659delC, 1078delT, ⌬I507, R345P, S1251N, E60X CF Poly-T 5T/7T/9T OLA CF OLA assay ⌬F508, F508C, ⌬I507, Q493X, V520F, 1717-1G→A, G542X, G551D, R553X, R560T, S549R, S549N, 3849+10kbC→T, 3849+4A→G, R1162X, 3659delC, W1282X, 3905insT, N1303K, G85E, 621+1G→T, R117H, Y122X, 711+1G→T, 1078delT, R347P, R347H, R334W, A455E, 1898+1G→A, 2183AA→G, 2789+5G→A b Figure 2 Mutation screening of exon 19 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene using polymerase chain reaction (PCR) followed by single-strand conformation polymorphism/heteroduplex (SSCP/HD) analysis on a silver-stained polyacrylamide gel. Login to comment

[hide] Intracellular chloride channels: critical mediator... Curr Pharm Des. 2005;11(21):2753-64. Suh KS, Yuspa SH
Intracellular chloride channels: critical mediators of cell viability and potential targets for cancer therapy.
Curr Pharm Des. 2005;11(21):2753-64., [PMID:16101453]

Abstract [show]
The passage of ions to form and maintain electrochemical gradients is a key element for regulating cellular activities and is dependent on specific channel proteins or complexes. Certain ion channels have been the targets of pharmaceuticals that have had impact on a variety of cardiovascular and neurological diseases. Chloride channels regulate the movement of a major cellular anion, and in so doing they in part determine cell membrane potential, modify transepithelial transport, and maintain intracellular pH and cell volume. There are multiple families of chloride channel proteins, and respiratory, neuromuscular, and renal dysfunction may result from mutations in specific family members. Interest in chloride channels related to cancer first arose when the multidrug resistance protein (MDR/P-glycoprotein) was linked to volume-activated chloride channel activity in cancer cells from patients undergoing chemotherapy. More recently, CLC, CLIC, and CLCA intracellular chloride channels have been recognized for their contributions in modifying cell cycle, apoptosis, cell adhesion, and cell motility. Moreover, advances in structural biology and high-throughput screening provide a platform to identify chemical compounds that modulate the activities of intracellular chloride channels thereby influencing chloride ion transport and altering cell behavior. This review will focus on several chloride channel families that may contribute to the cancer phenotype and suggest how they may serve as novel targets for primary cancer therapy.

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86 A variety of other mutations have been detected in CF patients [39] leading to ablation of protein synthesis (nonsense G542X, frameshift 394delTT, or splice junction 1717 G/A), blocked protein processing (missense N1303K or AA deletion in F508), blocked protein regulation (missense at G551D), altered conductance (missense R117H or R347P), and reduced protein synthesis (missense A455E, alternative splicing 3849 + 10kbC/T) [40]. Login to comment

[hide] Modifier genetics: cystic fibrosis. Annu Rev Genomics Hum Genet. 2005;6:237-60. Cutting GR
Modifier genetics: cystic fibrosis.
Annu Rev Genomics Hum Genet. 2005;6:237-60., [PMID:16124861]

Abstract [show]
Cystic fibrosis (CF) is the most common lethal autosomal recessive disorder in the Caucasian population, affecting about 30,000 individuals in the United States. The gene responsible for CF, the CF transmembrane conductance regulator (CFTR), was identified 15 years ago. Substantial variation in the many aspects of the CF phenotype among individuals with the same CFTR genotype demonstrates that factors independent of CFTR exert considerable influence on outcome in CF. To date, the majority of published studies investigating the cause of disease variability in CF report associations between candidate genes and some aspect of the CF phenotype. However, a definitive modifier gene for CF remains to be identified. Despite the challenges posed by searches for modifier effects, studies of affected twins and siblings indicate that genetic factors play a substantial role in intestinal manifestations. Identifying the factors contributing to variation in pulmonary disease, the primary cause of mortality, remains a challenge for CF research.

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42 Patients carrying a substitution of glutamic acid for alanine at codon 455 (A455E) have a slower rate of decline in lung function (30, 49). Login to comment

[hide] Nucleotide binding domains of human CFTR: a struct... Cell Mol Life Sci. 2005 Sep;62(18):2112-23. Eudes R, Lehn P, Ferec C, Mornon JP, Callebaut I
Nucleotide binding domains of human CFTR: a structural classification of critical residues and disease-causing mutations.
Cell Mol Life Sci. 2005 Sep;62(18):2112-23., [PMID:16132229]

Abstract [show]
Defective function of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) causes CF, the most frequent lethal inherited disease among the Caucasian population. The structure of this chloride ion channel includes two nucleotide-binding domains (NBDs), whose ATPase activity controls channel gating. Recently, the experimental structures of mouse and human CFTR NBD1 and our model of the human CFTR NBD1/NBD2 heterodimer have provided new insights into specific structural features of the CFTR NBD dimer. In the present work, we provide a structural classification of CF-causing mutations which may complement the existing functional classification. Our analysis also identified amino acid residues which may play a critical role in interdomain interaction and are located at the NBD1-NBD2 interface or on the surface of the dimer. In particular, a cluster of aromatic amino acids, which includes F508 and straddles the two NBDs, might be directly involved in the interaction of the NBD1/NBD2 heterodimer with the channel-forming membrane-spanning domains.

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132 Worth noting is that A455E and P574H are mild alleles, as they have been found associated with preserved pancreatic function and residual secretion of chloride; in addition, a correlation between the A455E mutation and mild pulmonary disease has also been reported [38]. Login to comment
336 333: 95-99 39 De Braekeleer M., Allard C., Leblanc J. P., Simard F. and Aubin G. (1997) Genotype-phenotype correlation in cystic fibrosis patients compound heterozygous for the A455E mutation. Hum. Genet. 101: 208-211 40 Van Oene M., Lukacs G. L. and Rommens J. M. (2000) Cystic fibrosis mutations lead to carboxyl-terminal fragments that highlight an early biogenesis step of the cystic fibrosis transmembrane conductance regulator. J. Biol. Chem. 275: 19577-19584 41 Ostedgaard L. S., Zeiher B. and Welsh M. J. (1999) Processing of CFTR bearing the P574H mutation differs from wild-type and deltaF508-CFTR. Login to comment

[hide] Cystic fibrosis, disease severity, and a macrophag... Am J Respir Crit Care Med. 2005 Dec 1;172(11):1412-5. Epub 2005 Sep 22. Plant BJ, Gallagher CG, Bucala R, Baugh JA, Chappell S, Morgan L, O'Connor CM, Morgan K, Donnelly SC
Cystic fibrosis, disease severity, and a macrophage migration inhibitory factor polymorphism.
Am J Respir Crit Care Med. 2005 Dec 1;172(11):1412-5. Epub 2005 Sep 22., 2005-12-01 [PMID:16179637]

Abstract [show]
RATIONALE: Macrophage migration inhibitory factor (MIF) is a key proinflammatory mediator. It contributes toward an exaggerated gram-negative inflammatory response via its ability to induce Toll-like receptor-4 expression. Studies have shown that MIF knockout mice have less aggressive Pseudomonas infection (compared with wild-type). OBJECTIVES: To assess whether a novel functional MIF polymorphism was associated with clinical prognosis in a patient cohort with chronic gram-negative infection, namely cystic fibrosis (CF). METHODS: Collected genomic DNA was analyzed via polymerase chain reaction amplification for the polymorphic region for the CATT repeat polymorphism. Individuals may have a 5-, 6-, 7-, or 8-CATT tetranucleotide repeat unit on each allele. The 5-CATT repeat allele exhibits the lowest MIF promoter activity. MEASUREMENTS AND MAIN RESULTS: Patients with stable CF (n = 167) and a matched control group (n = 166) were enrolled. In patients with CF, the MIF5(+) group had a decreased incidence of Pseudomonas aeruginosa colonization (odds ratio, 0.25; 95% confidence interval, 0.09-0.65; p = 0.004) and a significant reduction in the risk of pancreatic insufficiency (odds ratio, 0.27; 95% confidence interval, 0.07-1.0; p = 0.05). A trend toward milder disease activity in the MIF5(+) group was seen with all other parameters. CONCLUSIONS: The results support the concept of a regulatory role for MIF in CF.

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114 Recent work has suggested that the A455E (30, 34), 3849ϩ10 kb C→T (30, 35), and 2789ϩ5G→A (30, 36) are associated with mild clinical manifestations; these CFTR mutations were not seen in our patient population. Login to comment

[hide] A comparison of high-resolution melting analysis w... Am J Clin Pathol. 2005 Sep;124(3):330-8. Chou LS, Lyon E, Wittwer CT
A comparison of high-resolution melting analysis with denaturing high-performance liquid chromatography for mutation scanning: cystic fibrosis transmembrane conductance regulator gene as a model.
Am J Clin Pathol. 2005 Sep;124(3):330-8., [PMID:16191501]

Abstract [show]
High-resolution melting analysis (HRMA) was compared with denaturing high-performance liquid chromatography (dHPLC) for mutation scanning of common mutations in the cystic fibrosis transmembrane conductance regulator gene. We amplified (polymerase chain reaction under conditions optimized for melting analysis or dHPLC) 26 previously genotyped samples with mutations in exons 3, 4, 7, 9, 10, 11, 13, 17b, and 21, including 20 different genotypes. Heterozygous mutations were detected by a change in shape of the melting curve or dHPLC tracing. All 20 samples with heterozygous mutations studied by both techniques were identified correctly by melting (100% sensitivity), and 19 were identified by dHPLC (95% sensitivity). The specificity of both methods also was good, although the dHPLC traces of exon 7 consistently revealed 2 peaks for wild-type samples, risking false-positive interpretation. Homozygous mutations could not be detected using curve shape by either method. However, when the absolute temperatures of HRMA were considered, G542X but not F508del homozygotes could be distinguished from wild type. HRMA easily detected heterozygotes in all single nucleotide polymorphism (SNP) classes (including A/T SNPs) and 1- or 2-base-pair deletions. HRMA had better sensitivity and specificity than dHPLC with the added advantage that some homozygous sequence alterations could be identified. HRMA has great potential for rapid, closed-tube mutation scanning.

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18 Materials and Methods Sample Source and Study Design Eleven commercially genotyped samples were obtained from Coriell Cell Repositories, Coriell Institute for Medical Research, Camden, NJ (Y122X, R334W, R347P, A455E, I507del, F508del, F508C, G542X/G542X, R553X, R560T, and M1101K). Login to comment
31 ❚Table 1❚ Mutations Analyzed in the Study Position From 5' Exon (or Intron) Genotype* No. of Samples Nucleotide Change SNP Class† End/Amplicon Size (bp) 3 394delTT 1 Del‡ - 132/234 4 R117H 1 G→A 1 83/270 Y122X 1 T→A 4 99/270 I148T 2 T→C 1 176/270 Intron 4 621+1 2 G→T 2 233/270 7 R334W 1 C→T 1 208/345 R347P 1 G→C 3 248/345 9 A455E 2 C→A 2 155/263 10 I507del 1 Del‡ - 171/292 F508del 3 Del‡ - 174/292 F508del/F508del 1 Del - 174/292 F508C 1 T→G 2 175/292 11 G542X 1 G→T 2 90/175 G542X/G542X 1 G→T 2 90/175 G551D 1 G→A 1 118/175 R553X 2 C→T 1 123/175 R560T 1 G→C 3 145/175 13 2184delA 1 Del‡ - 356/458 17b M1101K 1 T→A 4 196/292 21 N1303K 1 C→G 3 175/250 bp, base pairs; SNP, single nucleotide polymorphism. Login to comment
75 Additional mutations in exons 9, 10, 11, and 21 included 7 heterozygous SNPs (A455E, F508C, G542X, G551D, R553X, R560T, and N1303K) and 2 heterozygous 3-base deletions (I507del and F508del). Login to comment

[hide] Newborn screening for cystic fibrosis in Wisconsin... J Pediatr. 2005 Sep;147(3 Suppl):S73-7. Rock MJ, Hoffman G, Laessig RH, Kopish GJ, Litsheim TJ, Farrell PM
Newborn screening for cystic fibrosis in Wisconsin: nine-year experience with routine trypsinogen/DNA testing.
J Pediatr. 2005 Sep;147(3 Suppl):S73-7., [PMID:16202788]

Abstract [show]
OBJECTIVE: To describe the development and follow-up confirmatory results of the routine cystic fibrosis (CF) newborn screening (NBS) program in Wisconsin. METHODS: CF NBS has been performed on a routine clinical basis in Wisconsin since July 1994. The 2-tiered immunoreactive trypsinogen (IRT)/DNA technique was used on dried blood on filter paper spots. From July 1994 to February 2002, mutation analysis was for the DeltaF508 allele. Beginning in March 2002, multimutation analysis of 25 CF mutations was performed. Infants with a positive result on NBS were seen in certified CF centers for sweat testing by means of quantitative pilocarpine iontophoresis, and families received genetic counseling. RESULTS: From July 1994 to February 2002, there were 120 cases of CF detected by means of NBS (509,794 infants screened), with 53 DeltaF508 homozygotes and 67 compound heterozygotes. There were 8 clinically diagnosed cases of CF (no DeltaF508 allele). The CF incidence was 1:3983 (95%CI, 1:3373-1:4774). From March 2002 to June 2003, multimutation analysis identified 21 cases of classic CF (90,142 infants screened). Sweat tests were successfully performed in infants younger than 1 month. CONCLUSIONS: Early diagnosis of CF through NBS was successfully performed, with an estimated sensitivity rate of 99% using the IRT/25 CFTR multimutation assay.

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30 Mutations included in this assay are 2184delA, A455E, DI507, DF508, G542X, G551D, R553X, R560T, 1717-1G>A, R1162X, 3659delC, N1303K, W1282X, R334W, R347P, 1078delT, R117H, I148T, 62111G>T, 278915G>A, 3849110kbC>T, G85E, 109811G>A, 71111G>T and 312011G>A. Login to comment

[hide] Two-tiered immunoreactive trypsinogen-based newbor... J Pediatr. 2005 Sep;147(3 Suppl):S83-8. Sontag MK, Hammond KB, Zielenski J, Wagener JS, Accurso FJ
Two-tiered immunoreactive trypsinogen-based newborn screening for cystic fibrosis in Colorado: screening efficacy and diagnostic outcomes.
J Pediatr. 2005 Sep;147(3 Suppl):S83-8., [PMID:16202790]

Abstract [show]
OBJECTIVE: To examine immunoreactive trypsinogen (IRT)-based screening for cystic fibrosis (CF) for recall rate, genotype distribution, and "borderline" sweat test results. STUDY DESIGN: CF newborn screening in Colorado began in 1982, and >1,153,000 infants were screened through 2002 with an IRT-based screen (IRT/IRT). RESULTS: We have identified 313 infants with CF, giving an overall incidence of 1 in 3684 and a Hispanic incidence of 1 in 6495. Fifty-five infants with meconium ileus (17.6%) were excluded from analysis. Fourteen infants with false-negative results were identified (5.4%). The average recall rate was 0.6%, with a positive predictive value of 4.7%. Ninety-three percent of the infants had at least 1 DeltaF508 mutation, and 98% of the infants had at least 1 mutation from the American College of Medical Genetics recommended panel. Six infants had hypertrypsinogenemia and borderline results on sweat tests (30-60 mmol/L). Increased variability in sweat chloride levels were seen in these infants compared with infants with homozygous DeltaF508. Three children with initial borderline results on sweat tests had CF diagnosed. CONCLUSIONS: The recall and false-negative rates of our IRT/IRT CF screening program are reported. Additionally, genotypes of the patients identified mirror the CF population genotypes, reflecting similar disease severity in the screened population. Finally, infants with persistent hypertrypsinogenemia and borderline sweat test results need long-term follow-up.

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86 The pancreatic sufficient mutations identified were 18981 5G>T, 278915G>A, A455E, G551S, G85E, I336K, P67L, R117C, R117H, R334W, R347P. Login to comment
129 Initial and repeat sweat chloride values and CFTR mutations in infants with borderline sweat test results Sweat Cl2 (mmol/L) Infant <6 months >6 months Genotype A 55 65 DF508/A455E B 50 - DF508/R117H C 45 77 DF508/R117C (7T/9T) D 33 26 DF508/- E 43 76 R117H/F575Y (7T,7T) F 43 25 312011G-A/- Figure 4. Login to comment

[hide] Cystic fibrosis transmembrane regulator gene carri... Gut. 2005 Nov;54(11):1661-2. McWilliams R, Highsmith WE, Rabe KG, de Andrade M, Tordsen LA, Holtegaard LM, Petersen GM
Cystic fibrosis transmembrane regulator gene carrier status is a risk factor for young onset pancreatic adenocarcinoma.
Gut. 2005 Nov;54(11):1661-2., [PMID:16227367]

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277 R McWilliams Department of Oncology and Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA W E Highsmith Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA K G Rabe, M de Andrade, L A Tordsen Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA Conflict of interest: None declared. Table 1 Comparison of CFTR mutation frequencies detected in the young onset pancreatic cancer cohort versus the clinical database Young onset pancreatic cancer cases (,60 y old at diagnosis, n = 166) Mayo Clinic clinical database reference group (n = 5349) No % No % CFTR mutation non-carriers 152 91.6 5132 95.9 CFTR mutation carriers 14 8.4 217 4.1 Mutation distribution DF508 12 85.7 155 71.4 R177H 1 7.1 28 12.9 G551D 6 2.8 2789+5G.A 6 2.8 G542X 4 1.8 N1303K 1 7.1 3 1.4 1717-1G.T 2 0.9 3849+10kbC.T 2 0.9 A455E 2 0.9 R1162X 2 0.9 R347H 1 0.5 R553X 1 0.5 3905insT 1 0.5 621+1G.T 1 0.5 W1282X 1 0.5 1898+1G.A 1 0.5 R560T 1 0.5 Young onset pancreatic cancer cases were more frequent carriers of the CFTR mutations compared with patients in the control database (odds ratio 2.18 (95% confidence interval 1.24-3.29); p = 0.006). Login to comment

[hide] Markedly elevated neonatal immunoreactive trypsino... Arch Dis Child. 2006 Mar;91(3):222-5. Epub 2005 Oct 21. Massie J, Curnow L, Tzanakos N, Francis I, Robertson CF
Markedly elevated neonatal immunoreactive trypsinogen levels in the absence of cystic fibrosis gene mutations is not an indication for further testing.
Arch Dis Child. 2006 Mar;91(3):222-5. Epub 2005 Oct 21., [PMID:16243854]

Abstract [show]
AIMS: To investigate the immunoreactive trypsinogen (IRT) values above the usual 99th centile laboratory cut-off and determine the value of offering further testing to those infants with a markedly elevated IRT but no cystic fibrosis transmembrane regulator (CFTR) gene mutation identified by the screening programme. METHODS: All babies born in Victoria, Australia, between 1991 and 2003, were screened by IRT followed by CF gene mutation analysis. RESULTS: Of the 806,520 babies born, 9268 with the highest IRT levels had CFTR mutation analysis. There were 123 DeltaF508 homozygotes and 703 heterozygotes (86 with CF, 617 carriers). A total of 8442 babies had no CFTR gene mutation, of whom 18 (0.21%) had CF. The total number of CF babies with IRT greater than the laboratory cut-off was 227 (2.4%). The IRT results of the CF patients were distributed normally, with the majority above the laboratory cut-off of newborn IRT results. There was no evidence of an excess of babies with CF in the very highest levels of IRT above the 99th centile. CONCLUSIONS: Only a small proportion of babies with a neonatal IRT >99th centile have CF. Additional CF testing for infants with an elevated IRT but no CFTR gene mutation has an extremely low yield, no matter how high the IRT result.

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222 *All patients underwent an extended CFTR mutation analysis for the following mutations in addition to DF508: G551D, R553X, G542X, R117H, N1303K, 621+1G-T, A455E, V520F, 1717-1G-A, W1282X, R1162X, 3849+10kbC-T, R347P, R334W, R560T, S549N. Login to comment

[hide] Mutations of the CFTR gene in idiopathic pancreati... Pancreas. 2005 Nov;31(4):350-2. Gullo L, Mantovani V, Manca M, Migliori M, Bastagli L, Pezzilli R
Mutations of the CFTR gene in idiopathic pancreatic hyperenzymemia.
Pancreas. 2005 Nov;31(4):350-2., [PMID:16258369]

Abstract [show]
OBJECTIVES: Idiopathic pancreatic hyperenzymemia is a new syndrome that is characterized by a chronic increase of serum pancreatic enzymes in the absence of pancreatic disease. The aim of this study was to assess whether mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene may have a role in the etiology of this hyperenzymemia. METHODS: Seventy subjects with idiopathic pancreatic hyperenzymemia, 44 men and 26 women (mean age, 48 years; range, 8-74 years), were studied. Thirteen of these 70 subjects had the familial form of the syndrome. The mutation analysis of the CFTR gene was carried out using diagnostic commercial kits for the simultaneous detection of 29 mutations and Tn polymorphism. RESULTS: Among the 70 subjects studied, 7 (10.0%) had CFTR gene mutations. None of these 7 subjects had the familial form of pancreatic hyperenzymemia. These mutations were DeltaF 508 in 1 subject, 2789 + 5 G > A in another subject, and T5 allele in the remaining 5. All these mutations were heterozygous, with the exception of 1 T5 allele that was homozygous in 1 subject. CONCLUSIONS: The frequencies of the mutations of the CFTR gene found in these subjects are similar to the carrier frequencies in the general Italian population. This finding does not support a role for CFTR gene mutations in the etiology of idiopathic pancreatic hyperenzymemia.

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52 A (i) 5 1078delT, R347P, R334W 7 A455E, Tn (i) 8, 9 DF508, DI507 10 G542X, 1717-1 G . Login to comment

[hide] Association of common haplotypes of surfactant pro... Pediatr Pulmonol. 2006 Mar;41(3):255-62. Choi EH, Ehrmantraut M, Foster CB, Moss J, Chanock SJ
Association of common haplotypes of surfactant protein A1 and A2 (SFTPA1 and SFTPA2) genes with severity of lung disease in cystic fibrosis.
Pediatr Pulmonol. 2006 Mar;41(3):255-62., [PMID:16429424]

Abstract [show]
Most individual cystic fibrosis transmembrane conductance regulator (CFTR) mutations appear not to correlate directly with severity of lung damage in cystic fibrosis (CF). Components of innate immunity, namely, mannose-binding lectin (MBL2), and surfactant protein A1 and A2 genes (SFTPA1 and SFTPA2), were shown to be critical in pulmonary host defenses. A pilot association study was conducted to identify genetic modifiers of lung disease in adult patients with CF. The structural and promoter (-221x/y) variants of MBL2, variants at codons 19, 50, 62, and 219 of SFTPA1, and at codons 9, 91, and 223 for SFTPA2, were studied in 135 adults with CF and compared to their forced expired volume in 1 sec (FEV1), diffusion of CO (DLCO), and other pulmonary scores. Predicted FEV1 was significantly lower in adults with the SFTPA1 6A3 allele and SFTPA2 1A1) allele (P = 0.01 and 0.009, respectively). The extended haplotype 6A3/1A1, which includes SFTPA1 and SFTPA2, was associated with lower pulmonary function, using FEV1 (P = 0.005) and poor pulmonary scores which were determined by American Medical Association, American Thoracic Society, and modified Shwachman-Kulczycki scores. Lower FEV1 and DLCO values were associated with MBL2 coding variants in those who had the DeltaF508 CFTR mutation (P = 0.03 and 0.004, respectively). These results support the current hypothesis that variants in pulmonary host defense molecules are potentially genetic modifiers of pulmonary disease in CF. Further work in larger populations is required to provide important new insights into the pathogenesis of CF.

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16 So far, there has been no evidence to correlate common mutations in CFTR, particularly DF508, with pulmonary deterioration, the most common complication of CF.1,2 There are rare mutations, such as A455E, that appear to correlate with milder pulmonary disease.3 There is, however, a strong correlation between selective CFTR mutations and pancreatic disease.4,5 A wide variation in pulmonary disease within families harboring identical CFTR mutations has led many experts to postulate that environmental and secondary genetic factors, also known as modifying genes (CF modifiers), could be important.6,7 It was demonstrated in animal models that genetic modifiers can influence outcomes in CF: there was an observed difference in severity of both intestinal and lung disease between CF micewith different genetic backgrounds.8,9 A genetic linkage analysis suggested that a modifier gene for meconium ileus is located in the proximal region of mouse chromosome 7, which is syntenic with human chromosome 19q13.9,10 1 Section on Genomic Variation, Pediatric Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. Login to comment
74 None of the rare CFTR mutations previously associated with mild pulmonary disease, such as A455E, was included.3 There was no significant association between primary CFTR mutations and the following measured pulmonary parameters: FEV1, scores for ATS, AMA, dyspnea, physical grade, Shwachman-and Kulczycki, and PA colonization. Login to comment

[hide] Detection of F508del mutation in cystic fibrosis t... Singapore Med J. 2006 Feb;47(2):129-33. Zilfalil BA, Sarina S, Liza-Sharmini AT, Oldfield NJ, Stenhouse SA
Detection of F508del mutation in cystic fibrosis transmembrane conductance regulator gene mutation among Malays.
Singapore Med J. 2006 Feb;47(2):129-33., [PMID:16435054]

Abstract [show]
INTRODUCTION: Cystic fibrosis (CF) is one of the common genetic disorders in the western world. It has been reported to be very rare in Asian populations. According to the Cystic Fibrosis Genetic Analysis Consortium, more than 1,000 mutations of the CF gene have been identified. The CF gene, named the cystic fibrosis transmembrane conductance regulator (CFTR), is located on chromosome 7 and composed of 27 exons. This study aims to detect possible CFTR gene mutations in Malays. METHODS: We analysed 50 blood samples from healthy Malays with no symptoms of CF. DNA was extracted from blood using commercially available extraction kits (Eppendorf, Germany). Identification of CFTR gene mutation was performed using the CF OLA (Oligonucleotide Ligation Assay) kit (Applied Biosystems, USA). The PCR-ligation products were electrophoresed on eight percent sequagel using an ABI PRISM 377 genetic analyser (Applied Biosystems, USA). Electrophoresis data was analysed using the Genotyper software and a report of the CF genotype for all loci tested was created using the CF Genotyper Template software. Out of 50, one sample (two percent) was detected to have the F508del mutation (3bp deletion at exon 10), which is one of the most common CFTR gene mutations in Caucasians. RESULTS: The F508del mutation allele was detected in one subject. This indicates that she was a CF carrier. CONCLUSION: We report the finding of a carrier of the F508del mutation of the CFTR gene in the Malay population. Our finding revealed that CF could also affect the Malay population. Larger studies are necessary to determine the exact gene frequency of this population.

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55 MUTATIONS R553X G551D 1507 del F508 del 1717-1 G>A G542X R560T R347P W1282X R334W 1078 Del T 3849 + 10KB C>T R1162X N1303K 3659 Del C A455E R117H 2183 AA>G 2789+5 G>A 1898 +1 G>A 621+1 G>T 711+1 G>T G85E S549N S549R V520F Q493X R347H 3849 +4 A>G 3905 INS T Y122X 4 software before running the gel electrophoresis in 1X TBE using ABI PRISM® 377 Genetic Analyzer (Applied Biosystems, USA) for 45 minutes. Login to comment

[hide] Rescue of DeltaF508-CFTR trafficking and gating in... Am J Physiol Lung Cell Mol Physiol. 2006 Jun;290(6):L1117-30. Epub 2006 Jan 27. Van Goor F, Straley KS, Cao D, Gonzalez J, Hadida S, Hazlewood A, Joubran J, Knapp T, Makings LR, Miller M, Neuberger T, Olson E, Panchenko V, Rader J, Singh A, Stack JH, Tung R, Grootenhuis PD, Negulescu P
Rescue of DeltaF508-CFTR trafficking and gating in human cystic fibrosis airway primary cultures by small molecules.
Am J Physiol Lung Cell Mol Physiol. 2006 Jun;290(6):L1117-30. Epub 2006 Jan 27., [PMID:16443646]

Abstract [show]
Cystic fibrosis (CF) is a fatal genetic disease caused by mutations in cftr, a gene encoding a PKA-regulated Cl(-) channel. The most common mutation results in a deletion of phenylalanine at position 508 (DeltaF508-CFTR) that impairs protein folding, trafficking, and channel gating in epithelial cells. In the airway, these defects alter salt and fluid transport, leading to chronic infection, inflammation, and loss of lung function. There are no drugs that specifically target mutant CFTR, and optimal treatment of CF may require repair of both the folding and gating defects. Here, we describe two classes of novel, potent small molecules identified from screening compound libraries that restore the function of DeltaF508-CFTR in both recombinant cells and cultures of human bronchial epithelia isolated from CF patients. The first class partially corrects the trafficking defect by facilitating exit from the endoplasmic reticulum and restores DeltaF508-CFTR-mediated Cl(-) transport to more than 10% of that observed in non-CF human bronchial epithelial cultures, a level expected to result in a clinical benefit in CF patients. The second class of compounds potentiates cAMP-mediated gating of DeltaF508-CFTR and achieves single-channel activity similar to wild-type CFTR. The CFTR-activating effects of the two mechanisms are additive and support the rationale of a drug discovery strategy based on rescue of the basic genetic defect responsible for CF.

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387 Genotype/phenotype correlations of Cl-channel function with disease severity show that mutations resulting in a only modest recovery toward wild-type levels (e.g., 5-30%) increase in CFTR expression or activity (e.g., A455E, 2,789 ϩ 5G3A, 5T, R334W, R347P, and R117H) and are typically associated with pancreatic sufficiency, a slower rate of pulmonary function decline, and a better severity index than that shown in patients with severe disease genotypes (5, 6, 10, 36, 49). Login to comment

[hide] On the discovery and development of CFTR chloride ... Curr Pharm Des. 2006;12(4):471-84. Becq F
On the discovery and development of CFTR chloride channel activators.
Curr Pharm Des. 2006;12(4):471-84., [PMID:16472140]

Abstract [show]
Chloride channels play important roles in vital cellular signalling processes contributing to homeostasis in both excitable and non-excitable cells. Since 1987, more than ten ion channel genes have been identified as causing human hereditary diseases among them the genes for the voltage-dependent chloride channel ClC-1 (myotonia) and the cystic fibrosis transmembrane conductance regulator (CFTR) protein (cystic fibrosis). The CFTR gene was cloned in 1989 and its protein product identified as an ATP-gated and phosphorylation-regulated chloride channel during the following two years. Since then, searching for potent and specific small molecules able to modulate normal and mutated CFTR has become a crucial endpoint in the field for both our understanding of the physiological role that CFTR plays in epithelial cells and more importantly for the development of therapeutic agents to cure cystic fibrosis (CF). It is predicted that a pharmacological approach would help not only to restore the defective transport activity of mutant CFTR but also to correct the regulatory function of CFTR. This review describes the evolution of CFTR pharmacology and how during the last five years, high throughput screening assays have been developed to identify novel molecules, some of them probably constituting a reservoir of future therapeutic agents for CF.

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52 Class V mutations (e.g. A455E, P574H) produce functional proteins with normal Cl-channel activity and regulation but at reduced rate of synthesis [19]. Login to comment

[hide] The relevance of sweat testing for the diagnosis o... Clin Biochem Rev. 2005 Nov;26(4):135-53. Mishra A, Greaves R, Massie J
The relevance of sweat testing for the diagnosis of cystic fibrosis in the genomic era.
Clin Biochem Rev. 2005 Nov;26(4):135-53., [PMID:16648884]

Abstract [show]
Cystic fibrosis (CF) is the most common inherited disorder of childhood. The diagnosis of CF has traditionally been based on clinical features with confirmatory evidence by sweat electrolyte analysis. Since 1989 it has been possible to also use gene mutation analysis to aid the diagnosis. Cloning of the cystic fibrosis transmembrane conductance regulator (CFTR) gene has advanced our understanding of CF, in particular the molecular basis of an expanded CF phenotype. However, because there are over 1000 mutations and 200 polymorphisms, many without recognised effects on CFTR, the molecular diagnosis can be troublesome. This has necessitated measurement of CFTR function with renewed interest in the sweat test. This review provides an overview of the clinical features of CF, the diagnosis and complex genetics. We provide a detailed discussion of the structure and function of CFTR and the classification of CFTR mutations. Sweat electrolyte analysis is discussed, from the physiology of sweating to the rigours of a properly performed sweat test and its interpretation. With this information it is possible to understand the relevance of the sweat test in the genomic era.

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117 In addition, at least for R117H, the amount of time that the channel is open is also reduced.75 R117H is a particularly interesting mutation as the affected CFTR function is also determined by the M470V polymorphism and the amount of protein produced.69,76 The clinical effects vary from pancreatic insufficient CF through to no clinical disease depending on the combination of these factors.77 Class V: Reduced Abundance Mutations in this group include missense, e.g. A455E (substitution of glutamic acid for alanine) and aberrant exon splicing, e.g. 3849 10kbC→T and the intron 8 polythymidine and TG repeat sequences that regulate exon 9 splicing.67,78 These mutations produce a reduced amount of CFTR transcript and low levels of functional protein that is translocated to the cell membrane. Login to comment
244 Highsmith and colleagues (1994) studied 23 patients with pulmonary disease characteristic of CF but with a normal sweat test and identified a point mutation in intron 19 of the CFTR gene, termed 3849+10kb C-T.15 This mutation produces an alternative splicing site and decreased amounts of CFTR mRNA can be detected.16 Thus, according to the classification of the CFTR mutations, this mutation falls into Class V.16,67 Other mutations associated with normal or borderline sweat electrolytes are R117H, D1152H, A455E, G551S and 2789+5G - A.9,24,78 An interesting phenotype, presenting with elevated sweat chloride concentration in the absence of other CF symptoms, has been described in a patient with a nonsense mutation, S1455X.105 This mutation truncates 26 amino acids from the C-terminus of the protein product. Login to comment

[hide] Variants in the glutamate-cysteine-ligase gene are... Am J Respir Crit Care Med. 2006 Aug 15;174(4):415-9. Epub 2006 May 11. McKone EF, Shao J, Frangolias DD, Keener CL, Shephard CA, Farin FM, Tonelli MR, Pare PD, Sandford AJ, Aitken ML, Kavanagh TJ
Variants in the glutamate-cysteine-ligase gene are associated with cystic fibrosis lung disease.
Am J Respir Crit Care Med. 2006 Aug 15;174(4):415-9. Epub 2006 May 11., 2006-08-15 [PMID:16690975]

Abstract [show]
BACKGROUND: Chronic progressive lung disease is the most serious complication of cystic fibrosis (CF). Glutathione plays an important role in the protection of the CF lung against oxidant-induced lung injury. OBJECTIVES: We hypothesized that a polymorphism in a novel candidate gene that regulates glutathione synthesis might influence CF lung disease. METHODS: In a cross-sectional study, subjects were recruited from CF clinics in Seattle and multiple centers in Canada. We tested for an association between CF lung disease and a functional polymorphism in the glutamate-cysteine ligase catalytic subunit (GCLC) gene. Multiple linear regression was used to test for association between polymorphisms of GCLC and severity of CF lung disease while adjusting for age, Pseudomonas aeruginosa infection, and cystic fibrosis transmembrane conductance regulator (CFTR) genotype. Analysis was repeated for patients with CF stratified by CFTR genotype. MEASUREMENTS AND MAIN RESULTS: A total of 440 subjects with CF participated in the study (51% male; mean [+/- SD] age, 26 +/- 11 yr; mean FEV(1), 62 +/- 28% predicted). In the total population, there was a trend toward an association between GCLC genotypes and CF lung disease (linear regression coefficient [SEM], 1.68 [1.0]; p = 0.097). In the stratified analysis, there was a highly significant association between GCLC genotype and CF lung function in subjects with a milder CFTR genotype (linear regression coefficient [SEM], 5.5 (1.7); p = 0.001). CONCLUSIONS: In patients with CF with a milder CFTR genotype, there is a strong association between functional polymorphisms of the GCLC gene and CF lung disease severity.

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63 Mild CFTR mutations (Class IV and V) ϭ R117H, R334W, G85E, R347P, 3849ϩ10KbC→T, 2789ϩ5G→A, A455E. Login to comment

[hide] Identification of CFTR, PRSS1, and SPINK1 mutation... Pancreas. 2006 Oct;33(3):221-7. Keiles S, Kammesheidt A
Identification of CFTR, PRSS1, and SPINK1 mutations in 381 patients with pancreatitis.
Pancreas. 2006 Oct;33(3):221-7., [PMID:17003641]

Abstract [show]
OBJECTIVES: Chronic pancreatitis is a progressive inflammatory disorder leading to irreversible exocrine and/or endocrine impairment. It is well documented that mutations in the cationic trypsinogen (PRSS1) gene can cause hereditary pancreatitis. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) and the serine protease inhibitor Kazal type 1 (SPINK1) genes are also associated with pancreatitis. METHODS: We analyzed 381 patients with a primary diagnosis of chronic or recurrent pancreatitis using the Ambry Test: Pancreatitis to obtain comprehensive genetic information for the CFTR, SPINK1, and PRSS1 genes. RESULTS: The results identified 32% (122/381) of patients with 166 mutant CFTR alleles, including 12 novel CFTR variants: 4375-20 A>G, F575Y, K598E, L1260P, G194R, F834L, S573C, 2789 + 17 C>T, 621+83 A>G, T164S, 621+25 A>G, and 3500-19 G>A. Of 122 patients with CFTR mutations, 5.5% (21/381) also carried a SPINK1 mutation, and 1.8% (7/381) carried a PRSS1 mutation. In addition, 8.9% (34/381) of all patients had 1 of 11 different SPINK1 mutations. Another 6.3% (24/381) of the patients had 1 of 8 different PRSS1 mutations. Moreover, 1.3% of the patients (5/381) had 1 PRSS1 and 1 SPINK1 mutation. A total 49% (185/381) of the patients carried one or more mutations. CONCLUSIONS: Comprehensive testing of the CFTR, PRSS1, and SPINK1 genes identified genetic variants in nearly half of all subjects considered by their physicians as candidates for genetic testing. Comprehensive test identified numerous novel variants that would not be identified by standard clinical screening panels.

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71 Patients With 1 CFTR Mutation CFTR Mutation 1 No. of Patients 1717-1 G9A 1 2789+5 G9A 1 3849+10kb C9T 2 3849+45 G9A 1 621+3 A9G 2 A1364V 1 A349V 1 A455E 1 D1152H 1 D1445N 1 deltaF508 16 E217G 1 F1286C 1 F316L 1 G542X 1 G551D 1 I148T 1 I807M 1 L206W 1 L967S 2 L997F 2 P55S 1 Q179K 1 Q220X 1 R117H 3 R1453W 1 R297Q 1 R31C 1 R668C 2 S1235R 1 S573C 1 S945L 1 V562A 1 V754M 2 Y1092X 1 Total patients 58 MutationsinboldfacewouldnothavebeendetectedbytheACOG/ACMGmutationpanel. Login to comment

[hide] CFTR genotype as a predictor of prognosis in cysti... Chest. 2006 Nov;130(5):1441-7. McKone EF, Goss CH, Aitken ML
CFTR genotype as a predictor of prognosis in cystic fibrosis.
Chest. 2006 Nov;130(5):1441-7., [PMID:17099022]

Abstract [show]
STUDY RATIONALE: Certain CFTR genotypes are associated with reduced mortality. The accuracy of using CFTR genotype as a predictor of survival and the mechanisms through which CFTR genotype influences survival are unknown. PARTICIPANTS: All patients with cystic fibrosis (CF) enrolled in the US Cystic Fibrosis Foundation national registry between 1993 and 2002. DESIGN: We examined the prognostic value of CFTR genotype, grouped into "high-risk" and "low-risk" categories based on the effect of their CFTR genotype on phenotype and protein production. MEASUREMENTS AND RESULTS: Clinical and genetic data were available from 15,651 patients with CF. Patients with a high-risk CFTR genotype had a greater than twofold increased risk of death compared to patients with a low-risk CFTR genotype (relative risk, 2.25; 95% confidence interval [CI], 1.77 to 2.84; p < 0.001). This association was partly explained by lung function, nutritional status, pancreatic insufficiency, and Pseudomonas aeruginosa colonization. Of the 1,672 patients who died, median age at death for the high-risk CFTR genotype was 24.2 years (interquartile range, 18.4 to 32.0 years) and for the low-risk CFTR genotype was 37.6 years (interquartile range, 28.8 to 47.9 years; p < 0.001). The positive predictive value of this classification method as a test to identify patients who died before or after their 30th birthday was 69% (95% CI, 67 to 72%) with a negative predictive value of 71% (95% CI, 60 to 80%). CONCLUSIONS: Grouping patients into high-risk and low-risk CFTR genotype categories is associated with significant differences in survival and median age at death. These differences are not fully explained by lung function, nutritional measures, pancreatic insufficiency, or P aeruginosa colonization. Modest reassurance about the likelihood of a milder than average course can be provided for CF patients with a low-risk CFTR genotype, although it should be acknowledged that substantial phenotypic variability exists.

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46 Alleles High-risk CFTR genotype Class I 2,131 G542X, R553X, W1282X, R1162X, 621-1G3T, 1717-1G3A, 1078⌬T, 3659⌬C Class II 11,231 ⌬F508, ⌬I507, N1303K, S549N, G85E Class III 783 G551D, R560T Low-risk CFTR genotype Class IV 391 R117H, R334W, R347P Class V 421 3849 ϩ 10KbC3T, 2789 ϩ 5G3A, A455E *Patients with both CFTR alleles in either class I, class II, or class III were grouped together as a high-risk genotype, while patients with at least one mutant allele in class IV and V were considered to have low-risk genotypes; 380 patients had both mutations in either class I, II, or III, while 314 patients had both mutations in either class IV or V (total, n ϭ 15,651). Login to comment

[hide] Heteropolymeric triplex-based genomic assay to det... PLoS One. 2007 Mar 21;2(3):e305. Daksis JI, Erikson GH
Heteropolymeric triplex-based genomic assay to detect pathogens or single-nucleotide polymorphisms in human genomic samples.
PLoS One. 2007 Mar 21;2(3):e305., [PMID:17375191]

Abstract [show]
Human genomic samples are complex and are considered difficult to assay directly without denaturation or PCR amplification. We report the use of a base-specific heteropolymeric triplex, formed by native duplex genomic target and an oligonucleotide third strand probe, to assay for low copy pathogen genomes present in a sample also containing human genomic duplex DNA, or to assay human genomic duplex DNA for Single Nucleotide Polymorphisms (SNP), without PCR amplification. Wild-type and mutant probes are used to identify triplexes containing FVL G1691A, MTHFR C677T and CFTR mutations. The specific triplex structure forms rapidly at room temperature in solution and may be detected without a separation step. YOYO-1, a fluorescent bis-intercalator, promotes and signals the formation of the specific triplex. Genomic duplexes may be assayed homogeneously with single base pair resolution. The specific triple-stranded structures of the assay may approximate homologous recombination intermediates, which various models suggest may form in either the major or minor groove of the duplex. The bases of the stable duplex target are rendered specifically reactive to the bases of the probe because of the activity of intercalated YOYO-1, which is known to decondense duplex locally 1.3 fold. This may approximate the local decondensation effected by recombination proteins such as RecA in vivo. Our assay, while involving triplex formation, is sui generis, as it is not homopurine sequence-dependent, as are "canonical triplexes". Rather, the base pair-specific heteropolymeric triplex of the assay is conformation-dependent. The highly sensitive diagnostic assay we present allows for the direct detection of base sequence in genomic duplex samples, including those containing human genomic duplex DNA, thereby bypassing the inherent problems and cost associated with conventional PCR based diagnostic assays.

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125 Sequence bglIR-WT25C 1 59-TATTTTGATTATAGGACATGAAGAT-39 DR01-WT15 2 59-GAGCCGAAGGGGCAG-39 CFTR delta F508-WT25C 3 59-TAGGAAACACCAAAGATGATATTTT-39 CFTR delta F508-MUT25C 4 59-ATAGGAAACACCA---ATGATATTTTCT-39 CFTR delta I507-WT25C 5 59-TAGGAAACACCAAAGATGATATTTT-39 CFTR delta I507-MUT25C 6 59-ATAGGAAACACCAAAGA---TATTTTCT-39 CFTR 3659delC-WT25C 7 59-TGGTTTGGTTGACTTGGTAGGTTTA-39 CFTR 3659delC-MUT25C 8 59-ATGGTTTGGTTGACTTG-TAGGTTTA-39 CFTR 3849+10kbCRT-WT25C 9 59-GTGTCTTACTCGCCATTTTAATACT-39 CFTR 3849+10kbCRT-MUT25C 10 59-GTGTCTTACTCACCATTTTAATACT-39 CFTR 2789+5GRA-WT25C11 59-AATAGGACATGGAATACTCACTTTC-39 CFTR 2789+5GRA-MUT25C 12 59-AATAGGACATGGAATATTCACTTTC-39 CFTR G551D-WT25C 13 59-ATTCTTGCTCGTTGACCTCCACTCA-39 CFTR G551D-MUT25C 14 59-ATTCTTGCTCGTTGATCTCCACTCA-39 CFTR 621+1GRT-WT25C 15 59-AAGTATTACCTTCTTATAAATCAAA-39 CFTR 621+1GRT-MUT25C16 59-AAGTATTAACTTCTTATAAATCAAA-39 CFTR R1162X-WT25C 17 59-AACTTAAAGACTCGGCTCACAGATC-39 CFTR R1162X-MUT25C 18 59-AACTTAAAGACTCAGCTCACAGATC-39 CFTR 1717-1GRA-WT25C 19 59-TGGAGATGTCCTATTACCAAAAATA-39 CFTR 1717-1GRA- MUT25C 20 59-TGGAGATGTCTTATTACCAAAAATA-39 CFTR A455E-WT25C 21 59-CCAGCAACCGCCAACAACTGTCCTC-39 CFTR A455E-MUT25C 22 59-CCAGCAACCTCCAACAACTGTCCTC-39 CFTR G542X-WT25C 23 59-ATTCCACCTTCTCCAAGAACTATAT-39 CFTR G542X-MUT25C 24 59-ATTCCACCTTCTCAAAGAACTATAT-39 CFTR N1303K-WT25C 25 59-TAGGGATCCAAGTTTTTTCTAAATG-39 CFTR N1303K-MUT25C 26 59-TAGGGATCCAACTTTTTTCTAAATG-39 CFTR R560T-WT25C 27 59-AGTTATTCACCTTGCTAAAGAAATT-39 CFTR R560T-MUT25C 28 59-AGTTATTCACGTTGCTAAAGAAATT-39 CFTR W1282X-WT25C 29 59-TTTCCTCCACTGTTGCAAAGTTATT-39 CFTR W1282X-MUT25C 30 59-TTTCCTTCACTGTTGCAAAGTTATT-39 MTHFR C677T-WT25C 31 59-TGATGATGAAATCGGCTCCCGCAGA-39 MTHFR C677T-MUT25C 32 59-TGATGATGAAATCGACTCCCGCAGA-39 FVL G1691A-WT25C 33 59-CCCTCTGTATTCCTCGCCTGTCCAG-39 FVL G1691A-MUT25C 34 59-CCCTCTGTATTCCTTGCCTGTCCAG-39 All 25-mer probes listed were antisense. Login to comment
704 Mutation Source Number of tests Percentage GC in probe sequence Percentage difference of mismatched TAF relative to perfect match TAF CFTR delta F508 blood 102 28% 2100% to 281% CFTR delta I507 blood 6 28% 2100% to 285% CFTR 3659delC blood 11 40% 2100% to 255% CFTR 3849+10kbCRT blood 9 36% 2100% to 282% CFTR 2789+5GRA blood 16 36% 2100% to 275% CFTR 2789+5GRA saliva 13 36% 2100% to 266% CFTR G551D blood 11 48% 2100% to 261% CFTR 621+1GRT blood 5 20% 2100% to 257% CFTR R1162X blood 6 44% 267% to 236% CFTR 1717-1GRA blood 12 32% 2100% to 258% CFTR A455E blood 9 60% 2100% to 289% CFTR G542X blood 6 36% 2100% to 260% CFTR N1303K blood 8 32% 2100% to 283% CFTR R560T blood 6 28% 2100% to 254% CFTR W1282X blood 14 36% 2100% to 274% MTHFR C677T blood 55 52% 2100% to 272% FVL G1691A blood 34 60% 2100% to 281% TAF indicates Triplex-Associated Fluorescence. doi:10.1371/journal.pone.0000305.t004 ..................................................................................... brighter when intercalated into complexes of identical short oligonucleotides, such as the probes used in our assay, than when a like number of YOYO-1 molecules were in the presence of genomic duplex DNA. Login to comment

[hide] Validation of cystic fibrosis mutation analysis us... Diagn Mol Pathol. 2007 Mar;16(1):57-9. Huang CK, Pan Q
Validation of cystic fibrosis mutation analysis using ABI 3130XL genetic analyzer.
Diagn Mol Pathol. 2007 Mar;16(1):57-9., [PMID:17471160]

Abstract [show]
Cystic fibrosis (CF) is one of the most common autosomal recessive diseases in the white population, with a prevalence estimate of 1 in 2500 to 3300 live births. CF is characterized by viscous mucus in the lungs with involvement of digestive and reproductive systems as well as sweat glands (excess salt loss). Treatment for CF patients is palliative. Over 1300 mutations have been identified in the CFTR gene. However, most of the mutations are at frequencies of <0.1% or represent private mutations. Although other methodologies are available for CF testing, the oligonucleotide ligation assay is a unique approach to mutation detection of point mutations, small deletions, and small insertions, and consists of 2 phases. Applied Biosystems 3130 Series Genetic Analyzers are the next-generation platform for low to medium throughput laboratories and deliver improved performance. One disadvantage of the Genetic Analyzers is that there is no template of instrument settings for POP-6 polymer using 36-cm array. The Abbott CF oligonucleotide ligation assay ASRs can be run only using POP-6 polymer. We are the first to have optimized the instrument settings for POP-6 polymer based on the template of Rapidseq36-POP6 for Abbott Diagnostics CF V3 ASRs. Several conditions were tried, and the conditions of sample injection voltage at 10,000 v and sample injection time at 5 seconds gave better results, which were with clearer peaks and lower background signals. Twenty cell line DNA samples from Coriell were analyzed, and the results were matched. In addition, Synthetic Controls from AcroMetrix were analyzed, and the results were same as expected. Also, about 1500 clinical samples were analyzed, and high-quality reportable results were obtained. In conclusion, our modified protocol is robust and reliable on this ABI 3130XL instrument.

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58 Mutation controls: to specifically assess the detection of CF mutations, 20 cell line DNA samples with mutations of R553X, 3659delC/delF508, delF508/Q493X, 711+ 1G>T/621+1G>T, 621+1G>T/delF508, G85E/ 621+1G>T, R560T/delF508, A455E/621+1G>T, N1303K, W1282X, G551D/R553X, 2789+5G>A/ 2789+5G>A, 3849+10C>T/3849+10C>T, 1717-1G>A, delF508/delF508, R347P/G551D, R334W, V520F, R117H/delF508/5T/9T, or G542X/G542X, respectively, from the Coriell Cell Repositories were analyzed. Login to comment

[hide] Analysis of cystic fibrosis gene mutations and ass... Genet Test. 2007 Summer;11(2):133-8. Knezevic J, Tanackovic G, Matijevic T, Barisic I, Pavelic J
Analysis of cystic fibrosis gene mutations and associated haplotypes in the Croatian population.
Genet Test. 2007 Summer;11(2):133-8., [PMID:17627383]

Abstract [show]
The aim of this study was to reveal the CFTR gene mutation status in the Croatian population as well as to establish the haplotypes associated with cystic fibrosis (CF) and those associated with specific gene mutations. A total of 48 unrelated CF patients from Croatia were examined. Among 96 tested alleles, we found nine different mutations: DeltaF508, 58.33%; G542X, 3.12%; N1303K, 2.08%; R1162X; 621 + 1G --> T; G85E; Y569C; E585X; and S466X, 1.04%. Analysis of three polymorphic loci revealed 15 different haplotypes. Two of them (21-23-13 and 21-17-13) occurred with a higher frequency (40% and 24%). Both of these haplotypes also carried a CFTR gene mutation (DeltaF508 or G542X) on 27 out of 32 chromosomes. Among 12 (of all together 29) CF alleles on which no mutations were found, we detected 10 different haplotypes. Because there are still no published data on the distribution of polymorphic loci in Croatia, nor haplotypes associated with mutations in the CFTR gene, our results greatly contribute to knowledge regarding the genetic background of CF in this region.

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39 INNOGENETICS INNO-LIPA CFTR 12 and INNO-LIPA CFTR 7 ϩ Tn diagnostic kits were used to assess the presence of the 29 mutations in CF patients; ⌬F508, ⌬I507, G542X, N1303K, 1717-1G Ǟ A, W1282X, G551D, R553X, S1251N, R560T, 3905insT, Q552X, 394delTT, G85E, E60X, 621 ϩ 1G Ǟ T, R117H, 1078delT, R347P, R334W, 2143delT, 2183AA Ǟ G, 2184delA, 711 ϩ 5G Ǟ A, 2789 ϩ 5G Ǟ A, R1162X, 3659delC, 3849 ϩ 10kbC Ǟ T, and A455E. Login to comment

[hide] Negative genetic neonatal screening for cystic fib... Clin Genet. 2007 Oct;72(4):374-7. Girardet A, Guittard C, Altieri JP, Templin C, Stremler N, Beroud C, des Georges M, Claustres M
Negative genetic neonatal screening for cystic fibrosis caused by compound heterozygosity for two large CFTR rearrangements.
Clin Genet. 2007 Oct;72(4):374-7., [PMID:17850636]

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34 If IRT at day 3 is positive (.65 ng/ml), the card is subjected to an ARMS Elucigen kit (Tepnel) testing for 30 common CF mutations (F508del, Y1092X, 1717-1G.A, G542X, W1282X, N1303K, 3849110kbC.T, 394delTT, 62111G.T, S1251N, G551D, R117H, R1162X, R334W, A455E, 2183AA.G, 3659delC, 1078delT, I507del, R347P, R553X, E60X, 1 8 1 1 11 . Login to comment

[hide] Scanning the cystic fibrosis transmembrane conduct... Clin Chem. 2007 Nov;53(11):1891-8. Epub 2007 Sep 21. Montgomery J, Wittwer CT, Kent JO, Zhou L
Scanning the cystic fibrosis transmembrane conductance regulator gene using high-resolution DNA melting analysis.
Clin Chem. 2007 Nov;53(11):1891-8. Epub 2007 Sep 21., [PMID:17890437]

Abstract [show]
BACKGROUND: Complete gene analysis of the cystic fibrosis transmembrane conductance regulator gene (CFTR) by scanning and/or sequencing is seldom performed because of the cost, time, and labor involved. High-resolution DNA melting analysis is a rapid, closed-tube alternative for gene scanning and genotyping. METHODS: The 27 exons of CFTR were amplified in 37 PCR products under identical conditions. Common variants in 96 blood donors were identified in each exon by high-resolution melting on a LightScanner(R). We then performed a subsequent blinded study on 30 samples enriched for disease-causing variants, including all 23 variants recommended by the American College of Medical Genetics and 8 additional, well-characterized variants. RESULTS: We identified 22 different sequence variants in 96 blood donors, including 4 novel variants and the disease-causing p.F508del. In the blinded study, all 40 disease-causing heterozygotes (29 unique) were detected, including 1 new probable disease-causing variant (c.3500-2A>T). The number of false-positive amplicons was decreased 96% by considering the 6 most common heterozygotes. The melting patterns of most heterozygotes were unique (37 of 40 pairs within the same amplicon), the exceptions being p.F508del vs p.I507del, p.G551D vs p.R553X, and p.W1282X vs c.4002A>G. The homozygotes p.G542X, c.2789 + 5G>A, and c.3849 + 10kbC>T were directly identified, but homozygous p.F508del was not. Specific genotyping of these exceptions, as well as genotyping of the 5T allele of intron 8, was achieved by unlabeled-probe and small-amplicon melting assays. CONCLUSIONS: High-resolution DNA melting methods provide a rapid and accurate alternative for complete CFTR analysis. False positives can be decreased by considering the melting profiles of common variants.

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145 2 223CϾT R31C 3 355CϾT R75X 386GϾA G85E 4 482GϾA R117H 575TϾC I148T 621 ؉ 1GϾTb 5 711 ؉ 1GϾT 7 1078delT 1132CϾT R334W 1150delA 1172GϾC R347P 8 1341 ϩ 18AϾCc 9 1496CϾA A455E 10 1651-1653del I507del 1653-1655del F508deld 11 1717 - 1GϾA 1756GϾT G542Xe 1784GϾA G551Db 1789CϾT R553Xf 1811GϾC R560T 12 1898 ؉ 1GϾA 13 2184delA 14b 2789 ؉ 5GϾAe 16 3120 ؉ 1GϾA 18 3500 - 2AϾTg 19 3616CϾT R1162X 3659delC Intron 19 3849 ؉ 10kbCϾTe 20 3978GϾA W1282X 21 4041CϾG N1303K 22 4178GϾA G1349Dc a Disease-causing variants recommended for genotyping by the ACMG (4) are in bold. Login to comment

[hide] One multiplex control for 29 cystic fibrosis mutat... Genet Test. 2007 Fall;11(3):256-68. Lebo RV, Bixler M, Galehouse D
One multiplex control for 29 cystic fibrosis mutations.
Genet Test. 2007 Fall;11(3):256-68., [PMID:17949287]

Abstract [show]
A simple approach is described to synthesize and clone an inexhaustible supply of any homozygous and/or heterozygous controls diluted with yeast genomic DNA to mimic human genome equivalents for use throughout the entire multiplex mutation assay. As a proof of principle, the 25 cystic fibrosis mutation panel selected by the American College of Medical Genetics and four additional mutant sequences were prepared as a single control mixture. The 29 CFTR mutations were incorporated into 17 gene fragments by PCR amplification of targeted sequences using mutagenic primers on normal human genomic DNA template. Flanking primers selected to bind beyond all published PCR primer sites amplified controls for most assay platforms. The 17 synthesized 433-933-bp CFTR fragments each with one to four homozygous mutant sequences were cloned into nine plasmid vectors at the multiple cloning site and bidirectionally sequenced. Miniplasmid preps from these nine clones were mixed and diluted with genomic yeast DNA to mimic the final nucleotide molar ratio of two CFTR genes in 6 x 10(9) bp total human genomic DNA. This mixture was added to control PCR reactions prior to amplification as the only positive control sample. In this fashion >200 multiplex clinical PCR analyses of >4,000 clinical patient samples have been controlled simultaneously for PCR amplification and substrate specificity for 29 tested mutations without cross contamination. This clinically validated multiplex cystic fibrosis control can be modified readily for different test formats and provides a robust means to control for all mutations instead of rotating human genomic controls each with a fraction of the mutations. This approach allows scores of additional mutation controls from any gene loci to be added to the same mixture annually.

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118 Replacing modified sequences near the A455E and N1303K mutations in clone #9 The initial clone 9 insert consisted of three amplicon fragments: (Fig. 2, #9, left) the 5Ј CFTR genomic segment with A455E from exon 9 and 5T from intron 8; (Fig. 2, #9, center) a middle segment with the 3849ϩ10kbC Ǟ T mutation in intron 19; and (Fig. 2, #9, right) the 3Ј insert with the N1303K mutation from exon 21 that all tested appropriately on the Innogenetics test strips (Fig. 3, f 9 strip pair). Login to comment
120 However, 10 nucleotide substitutions were found 34 to 257 basepairs downstream of the A455E site. Login to comment
133 Instead, our laboratory has prepared multiplex controls from aliquots of lin- MULTIPLEX CYSTIC FIBROSIS CONTROL 261 1 2 3 4 5 6 7 8 9 EXON/INTRON 4F4 R4 F11 R11INTRON 10/EXON 11 EXON 7R7 F7 R5 F9INTRON 5 R347P R334W 1078delT EXON 10R10 F10 R11 F11EXON 11/INTRON 10 INTRON 16R16 F16 R14b F14bINTRON 14b EXON 19F19 R19 F20 R20EXON 20 R1162X 3659delC INTRON 8/EXON 9F9 R9 F119 R119INTRON 19 5T A455E F21 R21EXON 21 N1303K EXON 10F10 R10 F3 R3EXON 3 1507 INTRON 12F12 R12 EXON 13R13 F13 2184delA FIG. 2. Login to comment

[hide] Distribution of CFTR mutations in Saguenay- Lac-Sa... Genet Med. 2008 Mar;10(3):201-6. Madore AM, Prevost C, Dorfman R, Taylor C, Durie P, Zielenski J, Laprise C
Distribution of CFTR mutations in Saguenay- Lac-Saint-Jean: proposal of a panel of mutations for population screening.
Genet Med. 2008 Mar;10(3):201-6., [PMID:18344710]

Abstract [show]
PURPOSE: Saguenay-Lac-Saint-Jean is a region located in the northeastern part of the Province of Quebec, Canada, and is characterized by a founder effect. In this region, it has been documented that the incidence of cystic fibrosis reached 1/902 live births between 1975 and 1988, three times higher than the average incidence of 1/2500 live births reported in other Caucasian populations. This corresponds to a carrier rate of 1/15. METHODS: Using genotyping data from the Canadian Consortium for Cystic Fibrosis Genetic Studies, this article describes the cystic fibrosis transmembrane conductance regulator profile of the cystic fibrosis population living in the Saguenay-Lac-Saint-Jean region and compares it with cystic fibrosis populations living in three other regions of the Province of Quebec. RESULTS: Significant differences in allelic frequencies of common mutations (as DeltaF508, 621 + 1G>T and A455E), and in percentage of covered allele with three or six mutations, were found in Saguenay-Lac-Saint-Jean compared to other regions. Based on this result, two mutation panels exceeding 90% sensitivity threshold are now proposed for cystic fibrosis carrier screening in this region. CONCLUSION: The implementation of the proposed carrier screening program could diminish the incidence of this disease in this region and allow future parents to make informed decisions about family planning.

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4 Results: Significant differences in allelic frequencies of common mutations (as ‚F508, 621 ϩ 1GϾT and A455E), and in percentage of covered allele with three or six mutations, were found in Saguenay-Lac-Saint-Jean compared to other regions. Login to comment
41 Three mutations are prevalent in the SLSJ population (‚F508, 621 ϩ 1GϾT, and A455E); according to data provided by the genetic counseling services and the Chicoutimi CF clinic, three other mutations are present in at least three different families (711 ϩ 1GϾT, 3199del6, and Y1092X). Login to comment
46 Similarly, the A455E mutation frequency is two to three times higher in the SLSJ population compared with the other Francophone population studied (P ϭ 0.004) and eight times higher than in the Anglophone and multiethnic population of Montreal (P ϭ 0.013). Login to comment
48 Altogether, the six mutations represent 95.89% of the CFTR allele of CF patients in the SLSJ population, whereas the proportions are 86.85, 85.27, and Table 2 Cystic fibrosis mutations present in the four populations studied Mutationa Allelic frequency (number of alleles [%]) Populationb 1 2 3 4 „F508 106 (62.35) 55 (72.37) 398 (72.36) 67 (57.78) 621 ؉ 1G>T 42 (24.71) 6 (7.89) 30 (5.45) 1 (0.85) A455E 12 (7.06) 2 (2.63) 14 (2.55) 1 (0.85) 3199del6 1 (0.59) 1 (1.32) 7 (1.27) 1 (0.85) 711 ؉ 1G>T 1 (0.59) 1 (1.32) 15 (2.73) 1 (0.85) Y1092X 1 (0.59) 1 (1.32) 5 (0.91) 0 R117C 2 (1.18) 0 0 0 ‚I507 1 (0.59) 2 (2.63) 10 (1.82) 0 L206W 1 (0.59) 1 (1.32) 9 (1.64) 0 R1158X 1 (0.59) 0 0 0 S489X 1 (0.59) 0 1 (0.18) 0 R553X 0 2 (2.63) 2 (0.36) 0 R334W 0 1 (1.32) 2 (0.36) 0 G542X 0 0 10 (1.82) 0 G85E 0 0 6 (1.09) 5 (4.24) N1303K 0 0 5 (0.91) 1 (0.85) IVS8-5T 0 0 4 (0.73) 0 W1282X 0 0 3 (0.55) 7 (5.93) R347P 0 0 1 (0.18) 2 (1.69) V520F 0 0 1 (0.18) 0 I1027T 0 0 1 (0.18) 0 R1066C/IVS 0 0 1 (0.18) 0 Q1313X 0 0 1 (0.18) 0 1898ϩ3GϾA 0 0 1 (0.18) 0 2183AAϾG 0 0 1 (0.18) 0 2951insA 0 0 1 (0.18) 0 G551D 0 0 0 2 (1.69) 1525-iG-A 0 0 0 2 (1.69) Y109C 0 0 0 1 (0.85) S549N 0 0 0 1 (0.85) 3154del1G 0 0 0 1 (0.85) UNKNOWN 1 (0.59) 4 (5.26) 20 (3.82) 25 (21.19) Number of alleles genotypedc 170 (100) 76 (100) 550 (100) 118 (100) a The six mutations included in the panels proposed are in bold. Login to comment
59 The three most common alleles in the SLSJ population are the ‚F508, 621 ϩ 1GϾT and A455E mutations. Login to comment
60 The frequency of the ‚F508 mutation is lower in the SLSJ population than in the other Francophones population (P ϭ 0.011) but the frequency of the 621 ϩ 1GϾT and A455E mutation is greater in this region than in any other region described here (P Ͻ 10-12 and P ϭ 0.004 for the Francophone populations, and P Ͻ 10-7 and P ϭ 0.013 for the Anglophone and multiethnic population, respectively). Login to comment
65 In the study of Rozen et al.,33 the authors also observed that the frequency for ‚F508 mutation was lower in SLSJ region (58.0%) than in the other regions of the PQ (71%) (P ϭ 0.047), and that subjects from the SLSJ region also have a higher 621 ϩ 1GϾT (23.2%) frequency than those of the remaining regions of the PQ (12.84%) (P ϭ 10-5 ).21,33 Four of our six most frequent mutations (‚F508, 621 ϩ 1GϾT, A455E, and 711 ϩ 1GϾT) are present in the ACMG- ACOG panel of 23 mutations, representing a detection rate of 94.71% in the SLSJ population. Login to comment
66 However, according to our results, a multimutation panel for carrier screening in the SLSJ region could include only the three principal mutations (‚F508, 621 ϩ 1GϾT, and A455E), covering a total of 94.12% of the CFTR alleles present in the SLSJ region (Fig. 3). Login to comment

[hide] Evaluation and use of a synthetic quality control ... Hum Mutat. 2008 Aug;29(8):1063-70. Berwouts S, Gordon JT, Rundell CA, Barton DE, Dequeker E
Evaluation and use of a synthetic quality control material, included in the European external quality assessment scheme for cystic fibrosis.
Hum Mutat. 2008 Aug;29(8):1063-70., [PMID:18470946]

Abstract [show]
Assuring high quality within the field of genetic testing is fundamental, as the results can have considerable impact on the patient and his or her family. The use of appropriate quality control (QC) samples is therefore essential. Diagnostic laboratories mainly use patient samples as QC material, which of course include a maximum of two mutations per sample. Bearing in mind that some assays (such as for cystic fibrosis [CF] testing) can test for more than 100 mutations, multiplex QC materials including more than two mutations could save valuable time and reagents. Based on this need, synthetic multiplex controls have been developed by Maine Molecular Quality Controls, Inc. (MMQCI) for CF. A synthetic control, containing six homozygous mutations and one polymorphism for CF transmembrane conductance regulator (CFTR), was evaluated by distributing it through the CF external quality assessment (EQA) scheme, along with the EQA samples in 2005. A total of 197 participants returned results of the yearly EQA scheme and 133 laboratories participated in the evaluation of the synthetic sample. Respectively, 76% and 73% of the participants were assigned as successful. This evaluation study revealed that the multiplex QC material performed well in the majority of assays and could be useful in method validation, as a tool to challenge interpretation skills, and as potential proficiency testing (PT) material.

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153 These very faint signals for wild-type R553X (c.1657C4T, p.Arg553X), wild-type R117H (c.350G4A, p.Arg117His), mutant G542X (c.1624G4T, p.Gly542X), and mutant A455E (c.1364C4A, p.Ala455Glu) signal were often not visible to the assessors on the copies of the raw data. Login to comment
157 ErrorTypes for the QCS in More Detail, for the LaboratoriesThat Used Only One Detection AssayÃ Genotype error Genotype Detection assay Number of labs Expected Reported Comment OLA-CFASR v2.0 1 R117 H hom ^ Correct on raw data INNO-LiPA CFTR36 1 R117 H hom R117 H het No signal for wt R117 H visible on copy of the raw data, could be very weak on original raw data INNO-LiPA CFTR36 1 R553X hom R553X het No signal for wt R553X visible on copy of the raw data, could be very weak on original raw dataI507del hom I507del/F508del Sequencing 2 R347 H hom ^ No complete raw data received Sequencing 1 I507del hom ^ No raw data received Additional mutation(s) reported Detection assay Number of labs Additional mutation(s) Comment OLA-CFASR v3.0 US 1 2184delAa hom Software called it INNO-LiPA CFTR36 3 A455E het (3labs), F508del (1lab) No signal for mut A455E visible on copy of the raw data, could be very weak on original raw data ARMS-ElucigeneTM CF29 3 2184delAa (3labs), R347P (3labs), 1717-1G4A (3labs), 3849110kbC4T (2labs) Cross reaction with 2183AA4Gb and R347 H and no full compatibility of MMQCI-CF-P1and ARMS method: no control bands visible ARMS-ElucigeneTM CF29 1CF-HT 1 2184delAa , R347P Cross reaction with 2183AA4Gb and R347H Sequencing 1 W1282X het, N1303 K het No raw data received ASPE-CFTR 4014 Tag-It 1 71111G4T het No raw data received Genotype error 1 additional mutation(s) reported Genotype Detection assay Number of labs Expected Reported Comment Additional mutation(s) Comment OLA-CFASR v3.0 EU 1 R117 H hom ^ No raw data received; probably 2183AA4Gb missed, but 2184delAa reported due to cross reaction 2184delAa hom No raw data received, probably due to cross-reaction with 2183AA4Gb 394delTTc hom 394delTTc het 2183AA4Gb hom ^ INNO-LiPA CFTR36 1 R553X hom I507del hom R553X het I507del/ F508del No signal for wt R553X visible on copy of the raw data, could be very weak on original raw data G542X het A455E het No signal for mut G542X and mut A455E visible on copy of the raw data, could be very weak on original raw data INNO-LiPA CFTR36 1 Italian regional 1 R553X hom R553X het No signal for wt R553X visible on copy of the raw data, could be very weak on original raw data Q552X het Misinterpretation: wt and mut signal for Q552X not visible, but this is a normal reaction pattern when R553X is hom present; the lab reported R553X het ARMS-ElucigeneTM CF29 1 I507del hom ^ No full compatibility of MMQCI- CF-P1 and ARMS method: no control bands R347P Cross-reaction with R347H2183AA4Gb hom ^ ÃIf the zygosity is not mentioned in the table, the laboratory did not report it. Login to comment
191 For example, reporting the weak bands for wild-type R553X (c.1657C4T, p.Arg553X) and R117 H (c.350G4A, p.Arg117His), mutant G542X (c.1624G4T, p.Gly542X) and A455E (c.1364C4A, p.Ala455Glu) seen by some of the laboratories using the INNO-LiPA assay could be explained in this respect. Login to comment
152 Finally, some laboratories using the INNO-LiPA assay obtained a very faint hybridization signal for the A445E (c.1364C4A, p.Ala455Glu) mutant probe, but a normal signal for the wild-type probe. Login to comment

[hide] Role of oxygen availability in CFTR expression and... Am J Respir Cell Mol Biol. 2008 Nov;39(5):514-21. Epub 2008 May 12. Guimbellot JS, Fortenberry JA, Siegal GP, Moore B, Wen H, Venglarik C, Chen YF, Oparil S, Sorscher EJ, Hong JS
Role of oxygen availability in CFTR expression and function.
Am J Respir Cell Mol Biol. 2008 Nov;39(5):514-21. Epub 2008 May 12., [PMID:18474670]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) serves a pivotal role in normal epithelial homeostasis; its absence leads to destruction of exocrine tissues, including those of the gastrointestinal tract and lung. Acute regulation of CFTR protein in response to environmental stimuli occurs at several levels (e.g., ion channel phosphorylation, ATP hydrolysis, apical membrane recycling). However, less information is available concerning the regulatory pathways that control levels of CFTR mRNA. In the present study, we investigated regulation of CFTR mRNA during oxygen restriction, examined effects of hypoxic signaling on chloride transport across cell monolayers, and related these findings to a possible role in the pathogenesis of chronic hypoxic lung disease. CFTR mRNA, protein, and function were robustly and reversibly altered in human cells in relation to hypoxia. In mice subjected to low oxygen in vivo, CFTR mRNA expression in airways, gastrointestinal tissues, and liver was repressed. CFTR mRNA expression was also diminished in pulmonary tissues taken from hypoxemic subjects at the time of lung transplantation. Environmental factors that induce hypoxic signaling regulate CFTR mRNA and epithelial Cl(-) transport in vitro and in vivo.

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234 For example, the A455E mutation results in marginally reduced function of CFTR and clinically mild pulmonary disease, a later age at diagnosis, and a substantially improved prognosis (37). Login to comment

[hide] Atypical cystic fibrosis and CFTR-related diseases... Clin Rev Allergy Immunol. 2008 Dec;35(3):116-23. Paranjape SM, Zeitlin PL
Atypical cystic fibrosis and CFTR-related diseases.
Clin Rev Allergy Immunol. 2008 Dec;35(3):116-23., [PMID:18493878]

Abstract [show]
Cystic fibrosis (CF), which is among the most common life-shortening recessive illnesses, is caused by mutations of the CF transmembrane conductance regulator (CFTR) and typically involves chronic infection and progressive obstruction of the respiratory tract as well as pancreatic exocrine insufficiency. Disease severity, to some extent, correlates with organ sensitivity to CFTR dysfunction and to the amount of functional protein, which is influenced by the type of mutation. Atypical CF represents approximately 2% of affected individuals, and includes cases presenting in adolescence or adulthood with pancreatic exocrine sufficiency, normal or borderline sweat chloride concentrations, or with a single predominant clinical feature. This review briefly describes diagnostic methods and phenotypic characteristics of classic and atypical CF, as well as CFTR-related diseases, conditions in which mutated CFTR may contribute to the pathogenesis but do not strictly fit established diagnostic criteria.

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64 Determination of the transepithelial nasal potential difference has been beneficial in establishing a CF Table 1 Mutations, sites, and molecular consequences associated with either an atypical presentation of CF respiratory disease or pancreatic sufficiency or late-onset pancreatic insufficiency (http:// www.genet.sickkids.on.ca) Mutation Site Consequence Atypical presentation M1210I Exon 19 Met to Ile at 1210 S1455X Exon 24 Ser to Stop at 1455 1811+18G→A Intron 11 mRNA splicing defect L346P Exon 7 Leu to Pro at 346 Y161D Exon 4 Tyr to Asp at 161 R31C Exon 2 Arg to Cys at 31 I752S Exon 13 Ile to Ser at 752 2811G/T Exon 15 Sequence variation Pancreatic sufficiency or late-onset pancreatic insufficiency R600G Exon 13 Arg to Gly at 600 D1152H Exon 18 Asp to His at 1152 Y89C Exon 3 Tyr to Cys at 89 R117H Exon 4 Arg to His at 117 D110E Exon 4 Asp to Glu at 110 296 + 3insT Intron 2 mRNA splicing defect E217G Exon 6a Glu to Gly at 217 V392G Exon 8 Val to Gly at 392 N1088D Exon 17b Asn to Asp at 1088 S737F Exon 13 Missense 1716+1G→A Intron 10 mRNA splicing defect R334W Exon 7 Arg to Trp at 334 R347P Exon 7 Arg to Pro at 347 A455E Exon 9 Ala to Glu at 455 P574H Exon 12 Pro to His at 574 3850-3T→G Intron 19 mRNA splicing defect diagnosis in many atypical cases. Login to comment

[hide] Genetic determinants and epidemiology of cystic fi... Diabetes Care. 2008 Sep;31(9):1789-94. Epub 2008 Jun 5. Adler AI, Shine BS, Chamnan P, Haworth CS, Bilton D
Genetic determinants and epidemiology of cystic fibrosis-related diabetes: results from a British cohort of children and adults.
Diabetes Care. 2008 Sep;31(9):1789-94. Epub 2008 Jun 5., [PMID:18535191]

Abstract [show]
OBJECTIVE: Longer survival of patients with cystic fibrosis has increased the occurrence of cystic fibrosis-related diabetes (CFRD). In this study we documented the incidence of CFRD and evaluated the association between mutations responsible for cystic fibrosis and incident CFRD, while identifying potential risk factors. RESEARCH DESIGN AND METHODS: This was a population-based longitudinal study of 50 cystic fibrosis speciality clinics in the U.K. Subjects included 8,029 individuals aged 0-64 years enrolled in the U.K. Cystic Fibrosis Registry during 1996-2005. Of these, 5,196 with data and without diabetes were included in analyses of incidence, and 3,275 with complete data were included in analyses of risk factors. Diabetes was defined by physician diagnosis, oral glucose tolerance testing, or treatment with hypoglycemic drugs. RESULTS: A total of 526 individuals developed CFRD over 15,010 person-years. The annual incidence was 3.5%. The incidence was higher in female patients and in patients with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in classes I and II. In a multivariate model of 377 cases of 3,275 patients, CFTR class (relative risk 1.70 [95% CI 1.16-2.49], class I or II versus others), increasing age, female sex, worse pulmonary function, liver dysfunction, pancreatic insufficiency, and corticosteroid use were independently associated with incident diabetes. CONCLUSIONS: The incidence of CFRD is high in Britain. CFTR class I and II mutations increase the risk of diabetes independent of other risk factors including pancreatic exocrine dysfunction.

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54 Genotypes associated with cystic fibrosis were coded into five established classes reflecting CFTR function of defective production, processing, regulation, conductance, and quantity of CFTR protein (12) as follows: I: G542X, R553X, W1282X, R1162X, 621-1G3T, 1717- 1G3 A, 1078⌬T, and 3659⌬C; II: ⌬F508, ⌬I507, N1303K, and S549N; III: G551Dand R560T; IV: R117H, R334W, G85E, and R347P; V: 3849ϩ5G3A, and A455E; and unknown: 711ϩIG3 T, 2184DA, and 1898ϩIG3 A. Login to comment

[hide] Guidelines for diagnosis of cystic fibrosis in new... J Pediatr. 2008 Aug;153(2):S4-S14. Farrell PM, Rosenstein BJ, White TB, Accurso FJ, Castellani C, Cutting GR, Durie PR, Legrys VA, Massie J, Parad RB, Rock MJ, Campbell PW 3rd
Guidelines for diagnosis of cystic fibrosis in newborns through older adults: Cystic Fibrosis Foundation consensus report.
J Pediatr. 2008 Aug;153(2):S4-S14., [PMID:18639722]

Abstract [show]
Newborn screening (NBS) for cystic fibrosis (CF) is increasingly being implemented and is soon likely to be in use throughout the United States, because early detection permits access to specialized medical care and improves outcomes. The diagnosis of CF is not always straightforward, however. The sweat chloride test remains the gold standard for CF diagnosis but does not always give a clear answer. Genotype analysis also does not always provide clarity; more than 1500 mutations have been identified in the CF transmembrane conductance regulator (CFTR) gene, not all of which result in CF. Harmful mutations in the gene can present as a spectrum of pathology ranging from sinusitis in adulthood to severe lung, pancreatic, or liver disease in infancy. Thus, CF identified postnatally must remain a clinical diagnosis. To provide guidance for the diagnosis of both infants with positive NBS results and older patients presenting with an indistinct clinical picture, the Cystic Fibrosis Foundation convened a meeting of experts in the field of CF diagnosis. Their recommendations, presented herein, involve a combination of clinical presentation, laboratory testing, and genetics to confirm a diagnosis of CF.

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142 Recommended panel of CF-causing mutations Missense, deletion, stop mutations Splicing, frameshift mutations G85E I507del R560T 621ϩ1GϾT 2789ϩ5GϾA R117H F508del R1162X 711ϩ1GϾT 3120ϩ1GϾA R334W G542X W1282X 1717-1GϾA 3659delC R347P G551D N1303K 1898ϩ1GϾA 3849ϩ10kbCϾT A455E R553X 2184delA Revised from the mutation panel for population screening for CF developed by the ACMG.77 Additional or alternative mutations present at significant frequencies in an ethnic population served by an NBS program may be added. Login to comment

[hide] Identification and characterization of CFTR gene m... Ann Hum Genet. 2009 Jan;73(1):26-33. Epub 2008 Sep 8. Sharma N, Singh M, Kaur G, Thapa BR, Prasad R
Identification and characterization of CFTR gene mutations in Indian CF patients.
Ann Hum Genet. 2009 Jan;73(1):26-33. Epub 2008 Sep 8., [PMID:18782298]

Abstract [show]
Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This study was performed on Indian CF patients (n = 50) to investigate the spectrum of mutations in the CFTR gene and their association with intragenic and extragenic marker haplotypes. We report identification of 14 previously known and eight novel mutations, namely 3986-3987delC, 876-6del4, 1792InsA, L69H, S158N, Q493L, I530L and E1329Q. The frequency of delta F508 was found to be 27%. Absolute linkage between delta F508 and the KM.19-GATT-TUB9-M470V-T854T haplotype (2-2-1-1-1) predicts a relatively recent appearance of delta F508 in Indian CF patients. Low frequency of delta F508 mutation and detection of eight novel and thirteen rare mutations reflect a heterogeneous spectrum of mutations in Indian CF patients. Failure to detect mutations in 34% of alleles indicates the possible presence of gross deletions involving one or more exons or may indicate the location of the molecular defects in either the noncoding parts of the gene or in the promoter region, which warrants analysis of those regions.

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42 CFTR mutations investigated by restriction analysis of PCR products were R334W (MspI), R347P (NcoI), A455E (AciI), 2789+5G-A (SSPI), R1162X (DdeI), and 3849+10kb C-T (HphI) (Gasparini et al., 1991; Dean et al., 1990; Kerem et al., 1990; Highsmith et al., 1990). Login to comment

[hide] Implication of the cystic fibrosis transmembrane c... Biochem Genet. 2008 Dec;46(11-12):847-56. Epub 2008 Sep 23. Sharma N, Singh M, Acharya N, Singh SK, Thapa BR, Kaur G, Prasad R
Implication of the cystic fibrosis transmembrane conductance regulator gene in infertile family members of Indian CF patients.
Biochem Genet. 2008 Dec;46(11-12):847-56. Epub 2008 Sep 23., [PMID:18810634]

Abstract [show]
Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CFTR gene. Among males with CF, 95% are infertile due to congenital absence of the vas deferens. We investigated the role of family history of infertility among CF subjects and characterized mutations in them. Among 50 CF subjects, four had a family history of infertility. A homozygous c.1521_1523delCTT mutation was detected in one, two had a compound heterozygous genotype (c.1521_1523delCTT/c.3717 + 10 kbC>T), and c.1521_1523delCTT mutation was identified on one allele of fourth CF subject. Genetic analysis of each infertile family members of CF subjects revealed the c.1521_1523delCTT mutation on one allele; however, no mutation could be identified on other allele. Haplotype analysis of the infertile family members showed that at least one of the alleles shared the same haplotype as that of the index case. It is suggested that the CFTR gene is implicated in the infertile members of the CF families. Failure to detect mutations on the other allele by SSCP analysis demands direct gene sequencing to detect mutations in the intronic or promoter region.

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41 CFTR mutations were investigated by restriction analysis of PCR products R334W (MspI), R347P (NcoI), A455E (AciI), 2789 ? Login to comment

[hide] Clinical practice and genetic counseling for cysti... Genet Med. 2008 Dec;10(12):851-68. Moskowitz SM, Chmiel JF, Sternen DL, Cheng E, Gibson RL, Marshall SG, Cutting GR
Clinical practice and genetic counseling for cystic fibrosis and CFTR-related disorders.
Genet Med. 2008 Dec;10(12):851-68., [PMID:19092437]

Abstract [show]
Cystic fibrosis transmembrane conductance regulator-related disorders encompass a disease spectrum from focal male reproductive tract involvement in congenital absence of the vas deferens to multiorgan involvement in classic cystic fibrosis. The reproductive, gastrointestinal, and exocrine manifestations of cystic fibrosis transmembrane conductance regulator deficiency are correlated with CFTR genotype, whereas the respiratory manifestations that are the main cause of morbidity and mortality in cystic fibrosis are less predictable. Molecular genetic testing of CFTR has led to new diagnostic strategies and will enable targeting of molecular therapies now in development. Older diagnostic methods that measure sweat chloride and nasal potential difference nonetheless remain important because of their sensitivity and specificity. In addition, the measurement of immunoreactive trypsinogen and the genotyping of CFTR alleles are key to newborn screening programs because of low cost. The multiorgan nature of cystic fibrosis leads to a heavy burden of care, thus therapeutic regimens are tailored to the specific manifestations present in each patient. The variability of cystic fibrosis lung disease and the variable expressivity of mild CFTR alleles complicate genetic counseling for this autosomal recessive disorder. Widespread implementation of newborn screening programs among populations with significant cystic fibrosis mutation carrier frequencies is expected to result in increasing demands on genetic counseling resources.

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56 Liver disease is second to pulmonary disease (plus organ transplantation complications) as a cause of mortality in CF (1.7% of deaths).26 Table 3 Core mutation panel carrier recommended by the ACMG for routine CF diagnostic testing and carrier screening of the general population7 Intronic mutations Exonic mutations Missense Nonsense In-Frame Deletion 621ϩ1GϾT G85E G542X ⌬I507 711ϩ1GϾT R117H R553X ⌬F508 1717-1GϾA R334W R1162X 1898ϩ1GϾA R347P W1282X 2184delA A455E 2789ϩ5GϾA G551D 3120ϩ1GϾA R560T 3659delC N1303K 3849ϩ10kbCϾT Endocrine manifestations of CF CF-related diabetes mellitus (CFRDM) may present in adolescence. Login to comment
98 For example, compound heterozygotes with ⌬F508/A455E have better pulmonary function than individuals who are homozygous for ⌬F508.10 In individuals with one or two R117H mutations, the severity of lung disease depends on the presence of a variation in the poly T tract of intron 8.44,45 Individuals with the 5T variant in cis configuration with the R117H mutation plus a second CFTR disease-causing mutation usually develop the lung disease of CF; but those individuals with the 7T variant in cis configuration with the R117H mutation plus a second CFTR disease-causing mutation have a highly variable phenotype, which can range from no symptoms to mild lung disease (Table 4).44,46 Because the A455E and R117H mutations are associated with pancreatic sufficiency, the less severe lung disease seen in individuals with these mutations could be the consequence of better nutritional status. Login to comment
104 The mechanism of partial penetrance of the 5T allele for CAVD is due to variation in the length of the adjacent TG tract (estimated at 60% in one study).50,51 Thus, interpretation of the disease implications of the 5T variant requires assessment of the number of TG repeats adjacent to the polythymidine tract.51 DIAGNOSIS AND TESTING Clinical phenotype Phenotypic features of CF include but are not limited to the following: ● Chronic suppurative sinopulmonary disease, with chronic coughandsputumproduction,chronicwheezeandairtrap- ping, obstructive lung disease on lung function tests, persistent colonization with pathogens commonly found in individuals with CF, chronic chest radiograph abnormalities, chronic pansinusitis, and/or digital clubbing Table 5 Proportion of CFTR genotypes detected in men with CAVD, based on pooled data4,47,57,116 Allele 1 Allele 2 Proportion (%)a 5T 5T 2 Other than 5T Other than 5T 26 5T Other than 5T 26 5T Wild type 8 Other than 5T Wild type 17 Wild type Wild type 22 a Percentages total to Ͼ100% because of rounding Table 4 CFTR genotype-phenotype correlations41,44,50,51,57,114-116 Allele 1 Allele 2 Range of phenotypes Classica Classic Classic ϾϾ nonclassic Milda Classic or mild Nonclassic Ͼ classic R117H/5T Classic or mild Nonclassic Ͼ classic R117H/7T Classic or mild Asymptomatic female or CAVD Ͼ nonclassic 5T/TG13 or TG12 Classic or mild CAVD or nonclassic CF ϾϾ asymptomatic carrier 5T/TG11 Classic or mild Asymptomatic Ͼ CAVD 7T or 9T Classic or mild Asymptomatic 7T or 9T 7T or 9T Asymptomatic a Classic refers to Class I, II, and III mutations (e.g., ⌬F508); mild refers to Class IV and V mutations (e.g., A455E) exclusive of R117H and 5T alleles (see Table 1). Login to comment

[hide] Heterogenous spectrum of CFTR gene mutations in In... Hum Reprod. 2009 May;24(5):1229-36. Epub 2009 Jan 30. Sharma N, Acharya N, Singh SK, Singh M, Sharma U, Prasad R
Heterogenous spectrum of CFTR gene mutations in Indian patients with congenital absence of vas deferens.
Hum Reprod. 2009 May;24(5):1229-36. Epub 2009 Jan 30., [PMID:19181743]

Abstract [show]
BACKGROUND: Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene can cause congenital bilateral absence of vas deferens. Yet, the spectrum and frequency of CFTR mutations in Indian males with congenital absence of vas deferens (CAVD) is unknown. METHODS: We investigated 50 Indian males, diagnosed with unilateral or bilateral absence of vas deferens at the PGIMER, Chandigarh, for the presence of the most common CFTR gene mutations as well as unknown mutations by single-strand conformation polymorphism followed by sequence analysis. RESULTS: This study led to the identification of 12 CFTR gene mutations on 48% of 100 Indian CAVD chromosomes. CFTR mutations were identified on both alleles in 11 patients (22%) and on one allele in 26 patients (52%). Novel CFTR mutations identified were L69H, F87I, G126S, F157C, E543A, Y852F and D1270E. The T5 allele (25%) and F508del (11%) were the most common mutations identified. The most common intragenic marker haplotype for F508del was 2111 (GATT, TUB9, M470V and T854T). No mutations could be detected in 13 CAVD patients (26%), including 4 with renal malformations. CONCLUSIONS: This study confirms the molecular heterogeneity of CFTR mutations in CAVD. Although the mutation detection rate is indeed lower in Indian CAVD patients, 74% of the patients tested had at least one CFTR mutation. CAVD alleles with no mutations suggest that other changes may be located at the non-screened sites that require extensive search by direct sequencing. Furthermore, the novel CFTR mutations identified require functional studies in a cell-based system.

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56 CFTR mutations investigated by restriction analysis of PCR products were R334W (MspI), R347P (NcoI), A455E (AciI), 2789 þ 5 . Login to comment

[hide] Non-classic cystic fibrosis associated with D1152H... Clin Genet. 2010 Apr;77(4):355-64. Epub 2009 Oct 15. Burgel PR, Fajac I, Hubert D, Grenet D, Stremler N, Roussey M, Siret D, Languepin J, Mely L, Fanton A, Labbe A, Domblides P, Vic P, Dagorne M, Reynaud-Gaubert M, Counil F, Varaigne F, Bienvenu T, Bellis G, Dusser D
Non-classic cystic fibrosis associated with D1152H CFTR mutation.
Clin Genet. 2010 Apr;77(4):355-64. Epub 2009 Oct 15., [PMID:19843100]

Abstract [show]
BACKGROUND: Limited knowledge exists on phenotypes associated with the D1152H cystic fibrosis transmembrane conductance regulator (CFTR) mutation. METHODS: Subjects with a D1152H allele in trans with another CFTR mutation were identified using the French Cystic Fibrosis Registry. Phenotypic characteristics were compared with those of pancreatic insufficient (PI) and pancreatic sufficient (PS) cystic fibrosis (CF) subjects in the Registry (CF cohort). RESULTS: Forty-two subjects with D1152H alleles were identified. Features leading to diagnosis included chronic sinopulmonary disease (n = 25), congenital absence of the vas deferens (n = 11), systematic neonatal screening (n = 4), and genetic counseling (n = 2). Median age at diagnosis was 33 [interquartile range (IQR, 24-41)] years in D1152H subjects. Median sweat chloride concentrations were 43.5 (39-63) mmol/l in D1152H subjects and were markedly lower than in PI and PS CF subjects (p < 0.05). Bronchiectasis was present in 67% of D1152H subjects, but Pseudomonas aeruginosa colonization and pancreatic insufficiency were present in <30% of subjects. Estimated rates of decline in forced expiratory volume in 1 s (FEV(1)) were lower in D1152H subjects vs PI CF subjects (p < 0.05). None of the D1152H subjects identified since 1999 had died or required lung transplantation. CONCLUSIONS: When present in trans with a CF-causing mutation, D1152H causes significant pulmonary disease, but all subjects had prolonged survival.

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42 The CF genetic analysis panel used in France seeks for 32 mutations: G85E, 394delTT, 621+1G>T, 711+1G>T, R334W, R347P, R347H, 1078delT, 5T/7T/9T, A455E, F508del, I507del, V520F, 1717-1G>A, G542X, G551D, R553X, R560T, S549R (T>G), S549N, 1898+1G>A, 2183AA>G, 2184delA, 2789+5G>A, 3120+1G>A, R1162X, 3659delC, 3849+10kbC>T, W1282X, 3905insT, 3876delA, N1303K. Login to comment

[hide] Do common in silico tools predict the clinical con... Clin Genet. 2010 May;77(5):464-73. Epub 2009 Jan 6. Dorfman R, Nalpathamkalam T, Taylor C, Gonska T, Keenan K, Yuan XW, Corey M, Tsui LC, Zielenski J, Durie P
Do common in silico tools predict the clinical consequences of amino-acid substitutions in the CFTR gene?
Clin Genet. 2010 May;77(5):464-73. Epub 2009 Jan 6., [PMID:20059485]

Abstract [show]
Computational methods are used to predict the molecular consequences of amino-acid substitutions on the basis of evolutionary conservation or protein structure, but their utility in clinical diagnosis or prediction of disease outcome has not been well validated. We evaluated three popular computer programs, namely, PANTHER, SIFT and PolyPhen, by comparing the predicted clinical outcomes for a group of known CFTR missense mutations against the diagnosis of cystic fibrosis (CF) and clinical manifestations in cohorts of subjects with CF-disease and CFTR-related disorders carrying these mutations. Owing to poor specificity, none of tools reliably distinguished between individual mutations that confer CF disease from mutations found in subjects with a CFTR-related disorder or no disease. Prediction scores for CFTR mutations derived from PANTHER showed a significant overall statistical correlation with the spectrum of disease severity associated with mutations in the CFTR gene. In contrast, PolyPhen- and SIFT-derived scores only showed significant differences between CF-causing and non-CF variants. Current computational methods are not recommended for establishing or excluding a CF diagnosis, notably as a newborn screening strategy or in patients with equivocal test results.

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64 Mutations in the CFTR gene grouped by clinical category Cystic fibrosis CFTR-related disease No disease T338I D614G L320V V920L L90S M470V H199R S1251N I203M G550R P111A I148T Q1291H R560K L1388Q L183I R170H I1027T S549R D443Y P499A L1414S T908N R668C S549N A455E E1401K Q151K G27E I1234L Y563N R347P C866R S1118C P1290S R75Q A559T V520F P841R M469V E1401G P67L G85E S50Y E1409K R933G G458V G178R Y1032C R248T I980K G85V V392G L973P L137H T351S R334W I444S V938G R792G R560T R555G L1339F D1305E P574H V1240G T1053I D58G G551D L1335P I918M F994C S945L L558S F1337V R810G D1152H G1247R P574S R766M D579G W1098R H949R F200I R352Q L1077P K1351E M244K L206W M1101K D1154G L375F N1303K R1066C E528D D110Y R347H R1070Q A800G P1021S S549K A1364V V392A damaging` (is supposed to affect protein function or structure) and 'probably damaging` (high confidence of affecting protein function or structure). Login to comment
57 PI prevalence and in silico prediction scores for 13 most frequent missense mutations identified in Canadian CF patients Mutation Total PI Total (PI + PS) PI prevalence Class PANTHER scorea POLYPHENa SIFTa p.R334W 1 9 0.11 CF-PS -7.4419 Possibly damaging 0.01 p.P67L 2 14 0.14 CF-PS -4.1736 Probably damaging 0 p.R347P 2 12 0.17 CF-PS -7.5259 Possibly damaging 0.01 p.R347H 1 5 0.20 CF-PS -6.8327 Possibly damaging 0 p.A455E 8 39 0.21 CF-PS -8.8641 Probably damaging 0 p.L206W 4 19 0.21 CF-PS -8.5817 Possibly damaging 0 p.P574H 4 7 0.57 CF-PI/PSb -8.1252 Probably damaging 0 p.G85E 15 24 0.63 CF-PI/PSb -7.3194 Possibly damaging 0 p.M1101K 22 33 0.67 CF-PI/PSb -5.8849 Probably damaging 0.01 p.R1066C 7 8 0.88 CF-PI -7.7424 Probably damaging 0 p.G551D 56 59 0.95 CF-PI -9.5654 Probably damaging 0 p.N1303K 47 49 0.96 CF-PI -9.7687 Probably damaging 0 p.V520F 7 7 1.00 CF-PI -7.1652 Benign 0 aPANTHER scores range from zero to negative values (maximum -12). Login to comment
122 However, it completely misclassified other well-established mutations with low PI prevalence scores (p.L206W, p.R334W, p.R347P and p.A455E). Login to comment
124 SIFT-generated low (deleterious) scores for missense mutations associated both with the highest (p.N1303K, p.G551D, p.V520F) and the lowest PI prevalence scores (p.A455E, p.P67L, p.L206W). Login to comment
127 While PolyPhen correctly classified the PI-CF mutations p.G551D and p.N1303K as 'probably damaging`, it misclassified the mild PS mutations p.A455E and p.P65L into the same category (Fig. S1c, supporting information online). Login to comment

[hide] Impact of gene patents and licensing practices on ... Genet Med. 2010 Apr;12(4 Suppl):S194-211. Chandrasekharan S, Heaney C, James T, Conover C, Cook-Deegan R
Impact of gene patents and licensing practices on access to genetic testing for cystic fibrosis.
Genet Med. 2010 Apr;12(4 Suppl):S194-211., [PMID:20393308]

Abstract [show]
Cystic fibrosis is one of the most commonly tested autosomal recessive disorders in the United States. Clinical cystic fibrosis is associated with mutations in the CFTR gene, of which the most common mutation among Caucasians, DeltaF508, was identified in 1989. The University of Michigan, Johns Hopkins University, and the Hospital for Sick Children, where much of the initial research occurred, hold key patents on cystic fibrosis genetic sequences, mutations, and methods for detecting them. Several patents, including the one that covers detection of the DeltaF508 mutation, are jointly held by the University of Michigan and the Hospital for Sick Children in Toronto, with Michigan administering patent licensing in the United States. The University of Michigan broadly licenses the DeltaF508 patent for genetic testing with >60 providers of genetic testing to date. Genetic testing is now used in newborn screening, diagnosis, and for carrier screening. Interviews with key researchers and intellectual property managers, a survey of laboratories' prices for cystic fibrosis genetic testing, a review of literature on cystic fibrosis tests' cost-effectiveness, and a review of the developing market for cystic fibrosis testing provide no evidence that patents have significantly hindered access to genetic tests for cystic fibrosis or prevented financially cost-effective screening. Current licensing practices for cystic fibrosis genetic testing seem to facilitate both academic research and commercial testing. More than 1000 different CFTR mutations have been identified, and research continues to determine their clinical significance. Patents have been nonexclusively licensed for diagnostic use and have been variably licensed for gene transfer and other therapeutic applications. The Cystic Fibrosis Foundation has been engaged in licensing decisions, making cystic fibrosis a model of collaborative and cooperative patenting and licensing practice.

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182 The ACMG specifically indicated that "Asian-Americans and Native Americans without significant Caucasian admixture should be informed of Table 1 Recommended core mutation panel for cystic fibrosis carrier screening in the general population Standard mutation panel R560T, ⌬F508a , R553Xb , R1162X, ⌬I507, 2184delA, G542X, G551Db , W1282X, N1303K, 621ϩ1G⌬T, R117H, 1717-1G⌬A, A455E, G85E, R334W, R347P, 711ϩ1G⌬T, 1898ϩ1G⌬A, 3849ϩ10kbC⌬T, 2789ϩ5G⌬A, 3659delC, and 3120ϩ1G⌬A Additional testable mutations I506Vc , I507Vc , F508Cc , and 5T/ 7T/9Td a University of Michigan/HSC Patent No. US 5,776,677. b Johns Hopkins University, Patent No. US 5,407,796. c Benign variants. Login to comment

[hide] Carrier screening for cystic fibrosis. Obstet Gynecol Clin North Am. 2010 Mar;37(1):47-59, Table of Contents. Dungan JS
Carrier screening for cystic fibrosis.
Obstet Gynecol Clin North Am. 2010 Mar;37(1):47-59, Table of Contents., [PMID:20494257]

Abstract [show]
Cystic fibrosis is the first genetic disorder for which universal screening of preconceptional or prenatal patients became a component of standard prenatal care. The molecular genetics and mutation profile of the CFTR gene are complex, with a wide range of phenotypic consequences. Carrier screening can facilitate risk assessment for prospective parents to have an affected offspring, although there remains a small residual risk for carrying a mutation even with a negative screening result. There are ethnic differences with respect to disease incidence and effectiveness of carrier testing, which may complicate counseling.

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102 However, in instances of a positive family history of affected individuals, but with no known mutation, further Table 2 Mutation panel recommended by ACOG and ACMG (listed in order of decreasing frequency in non-Hispanic Caucasian population) F508 del delI507 R347P R1162X G542X R553X 71111G>T 2184delA G551D R117H R560T 189811G>A 62111G>T 3849110kbC>T 3569delC R334W W1282X 1717À1G>T A455E 312011G>T N1303K 278915G>A G85E Data from Watson MS, Cutting GR, Desnick RJ, et al. Cystic fibrosis population carrier screening: 2004 revision of American College of Medical Genetics mutation panel. Login to comment

[hide] Folding and rescue of a cystic fibrosis transmembr... J Biol Chem. 2010 Aug 27;285(35):27033-44. Epub 2010 Jun 15. Da Paula AC, Sousa M, Xu Z, Dawson ES, Boyd AC, Sheppard DN, Amaral MD
Folding and rescue of a cystic fibrosis transmembrane conductance regulator trafficking mutant identified using human-murine chimeric proteins.
J Biol Chem. 2010 Aug 27;285(35):27033-44. Epub 2010 Jun 15., 2010-08-27 [PMID:20551307]

Abstract [show]
Impairment of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel causes cystic fibrosis, a fatal genetic disease. Here, to gain insight into CFTR structure and function, we exploited interspecies differences between CFTR homologues using human (h)-murine (m) CFTR chimeras containing murine nucleotide-binding domains (NBDs) or regulatory domain on an hCFTR backbone. Among 15 hmCFTR chimeras analyzed, all but two were correctly processed, one containing part of mNBD1 and another containing part of mNBD2. Based on physicochemical distance analysis of divergent residues between human and murine CFTR in the two misprocessed hmCFTR chimeras, we generated point mutations for analysis of respective CFTR processing and functional properties. We identified one amino acid substitution (K584E-CFTR) that disrupts CFTR processing in NBD1. No single mutation was identified in NBD2 that disrupts protein processing. However, a number of NBD2 mutants altered channel function. Analysis of structural models of CFTR identified that although Lys(584) interacts with residue Leu(581) in human CFTR Glu(584) interacts with Phe(581) in mouse CFTR. Introduction of the murine residue (Phe(581)) in cis with K584E in human CFTR rescued the processing and trafficking defects of K584E-CFTR. Our data demonstrate that human-murine CFTR chimeras may be used to validate structural models of full-length CFTR. We also conclude that hmCFTR chimeras are a valuable tool to elucidate interactions between different domains of CFTR.

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305 The different effects of K584E on CFTR processing and Cl-channel function are reminiscent of A455E and P574H, two CF mutations associated with a milder clinical phenotype (44). Login to comment
306 Although production of the mature forms of A455E and P574H was reduced and very much delayed, A455E had channel activity similar to and P574H had channel activity greater than that of WT-CFTR (44). Login to comment

[hide] Identification of the second CFTR mutation in pati... Asian J Androl. 2010 Nov;12(6):819-26. Epub 2010 Jul 26. Giuliani R, Antonucci I, Torrente I, Grammatico P, Palka G, Stuppia L
Identification of the second CFTR mutation in patients with congenital bilateral absence of vas deferens undergoing ART protocols.
Asian J Androl. 2010 Nov;12(6):819-26. Epub 2010 Jul 26., [PMID:20657600]

Abstract [show]
Congenital bilateral absence of vas deferens (CBAVD) is a manifestation of the mildest form of cystic fibrosis (CF) and is characterized by obstructive azoospermia in otherwise healthy patients. Owing to the availability of assisted reproductive technology, CBAVD patients can father children. These fathers are at risk of transmitting a mutated allele of the CF transmembrane conductance regulator (CFTR) gene, responsible for CF, to their offspring. The identification of mutations in both CFTR alleles in CBAVD patients is a crucial requirement for calculating the risk of producing a child with full-blown CF if the female partner is a healthy CF carrier. However, in the majority of CBAVD patients, conventional mutation screening is not able to detect mutations in both CFTR alleles, and this difficulty hampers the execution of correct genetic counselling. To obtain information about the most represented CFTR mutations in CBAVD patients, we analysed 23 CBAVD patients, 15 of whom had a single CFTR mutation after screening for 36 mutations and the 5T allele. The search for the second CFTR mutation in these cases was performed by using a triplex approach: (i) first, a reverse dot-blot analysis was performed to detect mutations with regional impact; (ii) next, multiple ligation-dependent probe amplification assays were conducted to search for large rearrangements; and (iii) finally, denaturing high-performance liquid chromatography was used to search for point mutations in the entire coding region. Using these approaches, the second CFTR mutation was detected in six patients, which increased the final detection rate to 60.8%.

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58 INNO-LiPA CFTR19 INNO-LiPA CFTR17 INNO-LiPA CFTR Italian regional [delta]F508 621+1G>T 1259insA G542X 3849+10kbC>T 4016insT N1303K 2183AA>G 4382delA W1282X 394delTT 852del22 G551D 2789+5G> A R1162X D579G 1717-1G>A 3659delC G1244E R553X R117H G1349D CFTRdele2,3 (21 kb) R334W I502T [delta]I507 R347P L1065P 711+1G>T G85E R1158X 3272-26A>G 3905insT 1078delT T338I R560T A455E S549R(A>C) 1898+1G>A S1251N 2143delA 711+5G>A 991del5 I148T E60X D1152H 3199del6 3120+1G>A 2184delA 1898+3A>G, R1070Q Q552X Poli-T tract variations R1066H R347H 621+3A>G R334Q E217G Abbreviation: CFTR, cystic fibrosis transmembrane conductance regulator. Login to comment

[hide] Type of CFTR mutation determines risk of pancreati... Gastroenterology. 2011 Jan;140(1):153-61. Epub 2010 Nov 9. Ooi CY, Dorfman R, Cipolli M, Gonska T, Castellani C, Keenan K, Freedman SD, Zielenski J, Berthiaume Y, Corey M, Schibli S, Tullis E, Durie PR
Type of CFTR mutation determines risk of pancreatitis in patients with cystic fibrosis.
Gastroenterology. 2011 Jan;140(1):153-61. Epub 2010 Nov 9., [PMID:20923678]

Abstract [show]
BACKGROUND & AIMS: Different mutations in the cystic fibrosis gene (CFTR) are associated with different functional status of the exocrine pancreas. We investigated whether CFTR genotypes determine the risk of pancreatitis in patients with cystic fibrosis (CF). METHODS: Patients with pancreatic-sufficient CF were identified from 2 CF population-based databases (N = 277; 62 with pancreatitis and 215 without pancreatitis); patients' genotypes and clinical characteristics were analyzed. The loss of pancreatic function associated with each CFTR genotype was determined based on the pancreatic insufficiency prevalence (PIP) score. RESULTS: Patients with pancreatitis were more likely to have genotypes associated with mild (70%) than moderate-severe (30%) PIP scores (P = .004). The cumulative proportion of patients who developed pancreatitis through to the age of 50 years was significantly greater for genotypes associated with mild (50%) than moderate-severe (27%) PIP scores (P = .006). The genotype associated with mild PIP scores had a hazard ratio of 2.4 for pancreatitis (95% confidence interval, 1.3-4.5; P = .006). Patients with pancreatitis were diagnosed with CF at an older median age than those without pancreatitis (14.9 years [interquartile range, 9.5-27.7] vs 9.3 years [interquartile range, 1.5-21.4]; P = .003) and had lower mean levels of sweat chloride than patients without pancreatitis (74.5 +/- 26.2 mmol/L vs 82.8 +/- 25.2 mmol/L; P = .03). CONCLUSIONS: Specific CFTR genotypes are significantly associated with pancreatitis. Patients with genotypes associated with mild phenotypic effects have a greater risk of developing pancreatitis than patients with genotypes associated with moderate-severe phenotypes. This observation provides further insight into the complex pathogenesis of pancreatitis.

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55 PIP Scores for Common, Well-Defined CFTR Mutations Mutation Canadian Consortium for CF Genetic Studies Verona CF Centre Mutation classTotal PI Total PIϩPS PIP score Total PI Total PIϩPS PIP score 621ϩ1GϾT 96 96 1.00 4 4 1.00 I-III 711ϩ1GϾT 36 36 1.00 1 1 1.00 I-III R553X 24 24 1.00 9 9 1.00 I-III I507del 11 11 1.00 12 12 1.00 I-III G542X 74 75 0.99 22 22 1.00 I-III F508del 1276 1324 0.96 181 188 0.96 I-III 1717-1GϾA 20 21 0.95 23 24 0.96 I-III W1282X 19 20 0.95 2 2 1.00 I-III N1303K 45 48 0.94 30 31 0.97 I-III R1162X 12 13 0.92 21 22 0.95 I-III G551D 59 67 0.88 0 0 - I-III G85E 16 22 0.73 4 5 0.80 I-III A455E 18 37 0.49 0 0 - IV-V 2789ϩ5GϾA 6 16 0.38 3 11 0.27 IV-V R334W 1 10 0.10 0 0 - IV-V 3849ϩ10kbCϾT 2 22 0.09 0 1 0.00 IV-V R117H 1 25 0.04 0 0 - IV-V NOTE. Login to comment
66 PIP scores for "moderate" mutations that have an inconsistent effect on pancreatic phenotype (PS and PI), which include 2789 ϩ 5GϾA and A455E, were correctly classified as intermediate (0.38 and 0.59, respectively). Login to comment

[hide] Mutations that permit residual CFTR function delay... Respir Res. 2010 Oct 8;11:140. Green DM, McDougal KE, Blackman SM, Sosnay PR, Henderson LB, Naughton KM, Collaco JM, Cutting GR
Mutations that permit residual CFTR function delay acquisition of multiple respiratory pathogens in CF patients.
Respir Res. 2010 Oct 8;11:140., [PMID:20932301]

Abstract [show]
BACKGROUND: Lung infection by various organisms is a characteristic feature of cystic fibrosis (CF). CFTR genotype effects acquisition of Pseudomonas aeruginosa (Pa), however the effect on acquisition of other infectious organisms that frequently precede Pa is relatively unknown. Understanding the role of CFTR in the acquisition of organisms first detected in patients may help guide symptomatic and molecular-based treatment for CF. METHODS: Lung infection, defined as a single positive respiratory tract culture, was assessed for 13 organisms in 1,381 individuals with CF. Subjects were divided by predicted CFTR function: 'Residual': carrying at least one partial function CFTR mutation (class IV or V) and 'Minimal' those who do not carry a partial function mutation. Kaplan-Meier estimates were created to assess CFTR effect on age of acquisition for each organism. Cox proportional hazard models were performed to control for possible cofactors. A separate Cox regression was used to determine whether defining infection with Pa, mucoid Pa or Aspergillus (Asp) using alternative criteria affected the results. The influence of severity of lung disease at the time of acquisition was evaluated using stratified Cox regression methods by lung disease categories. RESULTS: Subjects with 'Minimal' CFTR function had a higher hazard than patients with 'Residual' function for acquisition of 9 of 13 organisms studied (HR ranging from 1.7 to 3.78 based on the organism studied). Subjects with minimal CFTR function acquired infection at a younger age than those with residual function for 12 of 13 organisms (p-values ranging: < 0.001 to 0.017). Minimal CFTR function also associated with younger age of infection when 3 alternative definitions of infection with Pa, mucoid Pa or Asp were employed. Risk of infection is correlated with CFTR function for 8 of 9 organisms in patients with good lung function (>90%ile) but only 1 of 9 organisms in those with poorer lung function (<50%ile). CONCLUSIONS: Residual CFTR function correlates with later onset of respiratory tract infection by a wide spectrum of organisms frequently cultured from CF patients. The protective effect conferred by residual CFTR function is diminished in CF patients with more advanced lung disease.

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74 For Pa, the hazard ratio Table 1 Classification of CFTR alleles Category Mutation Specific mutations Class I Defective Protein Synthesis (nonsense, frameshift, aberrant splicing) 1078delT, 1154 insTC, 1525-2A > G, 1717-1G > A, 1898+1G > A, 2184delA, 2184 insA, 3007delG, 3120+1G > A, 3659delC, 3876delA, 3905insT, 394delTT, 4010del4, 4016insT, 4326delTC, 4374+1G > T, 441delA, 556delA, 621+1G > T, 621-1G > T, 711+1G > T, 875+1G > C, E1104X, E585X, E60X, E822X, G542X, G551D/R553X, Q493X, Q552X, Q814X, R1066C, R1162X, R553X, V520F, W1282X, Y1092X Class II Abnormal Processing and Trafficking A559T, D979A, ΔF508, ΔI507, G480C, G85E, N1303K, S549I, S549N, S549R Class III Defective Channel Regulation/Gating G1244E, G1349D, G551D, G551S, G85E, H199R, I1072T, I48T, L1077P, R560T, S1255P, S549 (R75Q) Class IV Decreased Channel Conductance A800G, D1152H, D1154G, D614G, delM1140, E822K, G314E, G576A, G622D, G85E, H620Q, I1139V, I1234V, L1335P, M1137V, P67L, R117C, R117P, R117H, R334W, R347H, R347P, R347P/ R347H, R792G, S1251N, V232D Class V Reduced Synthesis and/or Trafficking 2789+5G > A, 3120G > A, 3272-26A > G, 3849+10kbC > T, 5T variant, 621+3A > G, 711+3A > G, A445E, A455E, IVS8 poly T, P574H was increased 3 fold for those with 'Minimal` function when compared to those with 'Residual` function. Login to comment

[hide] CFTR transcription defects in pancreatic sufficien... J Med Genet. 2011 Apr;48(4):235-41. Epub 2010 Nov 20. Sheridan MB, Hefferon TW, Wang N, Merlo C, Milla C, Borowitz D, Green ED, Mogayzel PJ Jr, Cutting GR
CFTR transcription defects in pancreatic sufficient cystic fibrosis patients with only one mutation in the coding region of CFTR.
J Med Genet. 2011 Apr;48(4):235-41. Epub 2010 Nov 20., [PMID:21097845]

Abstract [show]
BACKGROUND: Patients with cystic fibrosis (CF) manifest a multisystem disease due to deleterious mutations in each gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). However, the role of dysfunctional CFTR is uncertain in individuals with mild forms of CF (ie, pancreatic sufficiency) and mutation in only one CFTR gene. METHODS: Eleven pancreatic sufficient (PS) CF patients with only one CFTR mutation identified after mutation screening (three patients), mutation scanning (four patients) or DNA sequencing (four patients) were studied. Bi-directional sequencing of the coding region of CFTR was performed in patients who had mutation screening or scanning. If a second CFTR mutation was not identified, CFTR mRNA transcripts from nasal epithelial cells were analysed to determine if any PS-CF patients harboured a second CFTR mutation that altered RNA expression. RESULTS: Sequencing of the coding regions of CFTR identified a second deleterious mutation in five of the seven patients who previously had mutation screening or mutation scanning. Five of the remaining six patients with only one deleterious mutation identified in the coding region of one CFTR gene had a pathologic reduction in the amount of RNA transcribed from their other CFTR gene (8.4-16% of wild type). CONCLUSIONS: These results show that sequencing of the coding region of CFTR followed by analysis of CFTR transcription could be a useful diagnostic approach to confirm that patients with mild forms of CF harbour deleterious alterations in both CFTR genes.

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15 Most PS-CF patients have two mutations in the coding regions of the CFTR gene.5 6 At least one mutation permits residual CFTR function, allowing the patient to escape the classic CF phenotype.7 8 While the 23 mutation ACMG panel includes several mutations frequently associated with PS-CF (eg, R117H [p.Arg117His], A455E [p.Arg455Glu], 2789+5G/A [c.2657+5G/A], and 3849+10kbC/T [c.3717+12191C/T]), it is not uncommon for a PS-CF patient to carry a rare CFTR mutation that is not present in the panel.9 Detection of less common mutations can be accomplished by use of extended mutation panels10 or by comprehensive analysis of the coding regions of the CFTR gene using scanning11e13 or DNA sequencing methods.14 Scanning techniques detect 85e99% of CFTR mutations15e17 while DNA sequencing has a higher sensitivity because it allows analysis of individual nucleotides.18 19 However, these techniques do not identify gene rearrangements and mutations in non-coding regions that affect splicing or expression of RNA transcripts. Login to comment

[hide] Low abundance of sweat duct Cl- channel CFTR in bo... Am J Physiol Regul Integr Comp Physiol. 2011 Mar;300(3):R605-15. Epub 2011 Jan 12. Brown MB, Haack KK, Pollack BP, Millard-Stafford M, McCarty NA
Low abundance of sweat duct Cl- channel CFTR in both healthy and cystic fibrosis athletes with exceptionally salty sweat during exercise.
Am J Physiol Regul Integr Comp Physiol. 2011 Mar;300(3):R605-15. Epub 2011 Jan 12., [PMID:21228336]

Abstract [show]
To understand potential mechanisms explaining interindividual variability observed in human sweat sodium concentration ([Na(+)]), we investigated the relationship among [Na(+)] of thermoregulatory sweat, plasma membrane expression of Na(+) and Cl(-) transport proteins in biopsied human eccrine sweat ducts, and basal levels of vasopressin (AVP) and aldosterone. Lower ductal luminal membrane expression of the Cl(-) channel cystic fibrosis transmembrane conductance regulator (CFTR) was observed in immunofluorescent staining of sweat glands from healthy young adults identified as exceptionally "salty sweaters" (SS) (n = 6, P < 0.05) and from patients with cystic fibrosis (CF) (n = 6, P < 0.005) compared with ducts from healthy young adults with "typical" sweat [Na(+)] (control, n = 6). Genetic testing of healthy subjects did not reveal any heterozygotes ("carriers") for any of the 39 most common disease-causing CFTR mutations in the United States. SS had higher baseline plasma [AVP] compared with control (P = 0.029). Immunostaining to investigate a potential relationship between higher plasma [AVP] (and sweat [Na(+)]) and ductal membrane aquaporin-5 revealed for all groups a relatively sparse and location-dependent ductal expression of the water channel with localization primarily to the secretory coil. Availability of CFTR for NaCl transport across the ductal membrane appears related to the significant physiological variability observed in sweat salt concentration in apparently healthy humans. At present, a heritable link between healthy salty sweaters and the most prevalent disease-causing CFTR mutations cannot be established.

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114 Mutations tested in this panel were ⌬F508, R334W, S549N, 3659delC, ⌬I507, I347P, A559T, S1255X, 1898ϩ1GϾA, R347H, N1303K, 1898ϩ5GϾT, 3876delA, A455E, 394delTT, 2183GGϾA, 3905insT, 3120ϩ1GϾA, V520F, 2184delA, G85E, Y1092X, 711ϩ1GϾT, 2307insA, Y122X, S549R, M1101K, 1078delT, 2789ϩ5GϾA, G551D, G542X, 621ϩ1GϾT, R560T, W1282X, 1717-1 GϾA, 3849 ϩ 10KbCϾT, R553X, R117H, and R1162X. Login to comment

[hide] Distribution of CFTR mutations in Eastern Hungaria... J Cyst Fibros. 2011 May;10(3):217-20. doi: 10.1016/j.jcf.2010.12.009. Epub 2011 Feb 4. Ivady G, Madar L, Nagy B, Gonczi F, Ajzner E, Dzsudzsak E, Dvorakova L, Gombos E, Kappelmayer J, Macek M Jr, Balogh I
Distribution of CFTR mutations in Eastern Hungarians: relevance to genetic testing and to the introduction of newborn screening for cystic fibrosis.
J Cyst Fibros. 2011 May;10(3):217-20. doi: 10.1016/j.jcf.2010.12.009. Epub 2011 Feb 4., [PMID:21296036]

Abstract [show]
BACKGROUND: The aim of this study was characterization of an updated distribution of CFTR mutations in a representative cohort of 40 CF patients with the classical form of the disease drawn from Eastern Hungary. Due to the homogeneity of the Hungarian population our data are generally applicable to other regions of the country, including the sizeable diaspora. METHODS: We utilized the recommended "cascade" CFTR mutation screening approach, initially using a commercial assay, followed by examination of the common "Slavic" deletion CFTRdele2,3(21kb). Subsequently, the entire CFTR coding region of the CFTR gene was sequenced in patients with yet unidentified mutations. RESULTS: The Elucigene CF29(Tm) v2 assay detected 81.25% of all CF causing mutations. An addition of the CFTRdele2,3(21kb) increased the mutation detection rate to 86.25%. DNA sequencing enabled us to identify mutations on 79/80 CF alleles. Mutations [CFTRdele2,3(21kb), p.Gln685ThrfsX4 (2184insA) were found at an unusually high frequency, each comprising 5.00% of all CF alleles. CONCLUSION: We have identified common CF causing mutations in the Hungarian population with the most common mutations (p.Phe508del, p.Asn1303Lys, CFTRdele2,3(21kb), 2184insA, p.Gly542X, and p.Leu101X), comprising over 93.75% of all CF alleles. Obtained data are applicable to the improvement of DNA diagnostics in Hungary and beyond, and are the necessary prerequisite for the introduction of a nationwide "two tier" CF newborn screening program.

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33 The Elucigene CF29Tm v2 Kit is capable of detecting the following mutations: p.Asp1152His (c.3454 GNC), c.1585-1 GNA, p.Gly542X (c.1624 GNT), p.Trp1282X (c.3846 GNA), p.Asn1303Lys (c.3909 C NG), p.Phe508del (c.1521_ 1523delCTT), c.3717+12191 CNT, p.Leu88IlefsX22 (c.262_ 263delTT), c.489+1 GNT, p.Ser1251Asn (c.3752 GNA), p.Gly551Asp (c.1652 GNA), p.Arg117His (c.350 GNA), p.Arg1162X (c.3484 CNT), p.Arg334Trp (c.1000 CNT), p.Ala455Glu (c.1364 CNA), p.Lys684SerfsX38 (c.2051_ 2052delAAinsG), p.Lys1177SerfsX15 (c. Login to comment

[hide] Association between genotype and pulmonary phenoty... J Cyst Fibros. 2011 May;10(3):187-92. doi: 10.1016/j.jcf.2011.01.005. Epub 2011 Feb 26. Geborek A, Hjelte L
Association between genotype and pulmonary phenotype in cystic fibrosis patients with severe mutations.
J Cyst Fibros. 2011 May;10(3):187-92. doi: 10.1016/j.jcf.2011.01.005. Epub 2011 Feb 26., [PMID:21354377]

Abstract [show]
BACKGROUND: Despite numerous studies a clear relationship between genotype and pulmonary phenotype has not been established within the group pancreatic insufficient cystic fibrosis (CF) patients. We studied the relationship between class I and class II mutations and pulmonary function in Swedish patients with known CFTR functional classification. METHODS: 170 CF patients with two class II mutations, 18 with two class I mutations and 78 with a combination of class I and II mutations were included in the study. Spirometry was performed when patients were in an optimal clinical condition. RESULTS: Patients with two class I mutations had lower lung function (FEV(1) and FVC) compared to the group with either a combination of class I and II mutations or two class II mutations. CONCLUSION: CF patients carrying two class I mutations risk developing more severe lung disease compared to patients with at least one class II mutation.

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98 Class I Class II Class III Class IV Class V 1717-1 G-NA F508del G551D 297 C-NA 2789+5 G-NA 3659delC S945L R560T R117C 3849+10 kb CNT 394delTT R347P A455E R553X T 3381 3849+10 kb C-T 621+1 G-NT E60X G542X W79R W1282X decline of pulmonary function was more rapid in patients with pancreatic insufficiency, mainly class II mutations, compared to CF patients with normal pancreatic function [4]. Login to comment

[hide] Optimal DNA tier for the IRT/DNA algorithm determi... J Cyst Fibros. 2011 Jul;10(4):278-81. Epub 2011 Mar 8. Baker MW, Groose M, Hoffman G, Rock M, Levy H, Farrell PM
Optimal DNA tier for the IRT/DNA algorithm determined by CFTR mutation results over 14 years of newborn screening.
J Cyst Fibros. 2011 Jul;10(4):278-81. Epub 2011 Mar 8., [PMID:21388895]

Abstract [show]
BACKGROUND: There has been great variation and uncertainty about how many and what CFTR mutations to include in cystic fibrosis (CF) newborn screening algorithms, and very little research on this topic using large populations of newborns. METHODS: We reviewed Wisconsin screening results for 1994-2008 to identify an ideal panel. RESULTS: Upon analyzing approximately 1 million screening results, we found it optimal to use a 23 CFTR mutation panel as a second tier when an immunoreactive trypsinogen (IRT)/DNA algorithm was applied for CF screening. This panel in association with a 96th percentile IRT cutoff gave a sensitivity of 97.3%, but restricting the DNA tier to F508del was associated with 90% (P<.0001). CONCLUSIONS: Although CFTR panel selection has been challenging, our data show that a 23 mutation method optimizes sensitivity and is advantageous. The IRT cutoff value, however, is actually more critical than DNA in determining CF newborn screening sensitivity.

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75 CFTR mutationa Proportion of allele Frequency of allele (%) Cumulative detection (%)b F508del 137/214 64.02 92.52 3849+10KbCNT 6/214 2.80 92.52c G542X 5/214 2.34 94.39 N1303K 4/214 1.87 98.13 R117H 4/214 1.87 99.07 R553X 3/214 1.40 99.07 1717-1GNA 2/214 0.93 99.07 G551D 1/214 0.47 100 R347P 1/214 0.47 100 A455E 1/214 0.47 100 W1282X 1/214 0.47 100 621+1GNT 1/214 0.47 100 a The other 11 mutations in ACMG 23 mutation panel are G85E, 711+1GNT, R334W, I507del, R560T, 1898+1GNA, 2184delA, 2789+5GNA, 3120+1GNA, R1162X and 3659delC. Login to comment

[hide] Cystic fibrosis carrier testing in an ethnically d... Clin Chem. 2011 Jun;57(6):841-8. Epub 2011 Apr 7. Rohlfs EM, Zhou Z, Heim RA, Nagan N, Rosenblum LS, Flynn K, Scholl T, Akmaev VR, Sirko-Osadsa DA, Allitto BA, Sugarman EA
Cystic fibrosis carrier testing in an ethnically diverse US population.
Clin Chem. 2011 Jun;57(6):841-8. Epub 2011 Apr 7., [PMID:21474639]

Abstract [show]
BACKGROUND: The incidence of cystic fibrosis (CF) and the frequency of specific disease-causing mutations vary among populations. Affected individuals experience a range of serious clinical consequences, notably lung and pancreatic disease, which are only partially dependent on genotype. METHODS: An allele-specific primer-extension reaction, liquid-phase hybridization to a bead array, and subsequent fluorescence detection were used in testing for carriers of 98 CFTR [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)] mutations among 364 890 referred individuals with no family history of CF. RESULTS: One in 38 individuals carried one of the 98 CFTR mutations included in this panel. Of the 87 different mutations detected, 18 were limited to a single ethnic group. African American, Hispanic, and Asian individuals accounted for 33% of the individuals tested. The mutation frequency distribution of Caucasians was significantly different from that of each of these ethnic groups (P < 1 x 10(1)). CONCLUSIONS: Carrier testing using a broad mutation panel detects differences in the distribution of mutations among ethnic groups in the US.

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65 The median fluorescent intensity was determined, and the presence or absence of mutant and wild-type alleles was evaluated from the ratio of the mutant signal to the wild-type signal for the following mutations: c.1155_1156dupTA, c.2657ϩ5GϾA, c.3717ϩ12191CϾT, p.A455E, p.D1152H, p.F508del, p.G542X, p.G551D, p.I507del, p.L206W, p.N1303K, p.R117H, p.W1282X, and c.54-5940_ 273ϩ10250del21kb. Login to comment

[hide] Assessment of CFTR function in homozygous R117H-7T... J Cyst Fibros. 2011 Sep;10(5):326-32. Epub 2011 Apr 19. de Nooijer RA, Nobel JM, Arets HG, Bot AG, van Berkhout FT, de Rijke YB, de Jonge HR, Bronsveld I
Assessment of CFTR function in homozygous R117H-7T subjects.
J Cyst Fibros. 2011 Sep;10(5):326-32. Epub 2011 Apr 19., [PMID:21507732]

Abstract [show]
BACKGROUND: R117H is a frequent missense mutation included in most CFTR mutation panels. However knowledge about the residual function of R117H-CFTR channels in cystic fibrosis-affected organs, e.g. airways, intestines and sweat glands is presently lacking. METHODS: We evaluated clinical CF symptoms and assessed CFTR function by sweat tests, nasal potential difference and intestinal current measurements in 2 homozygous R117H individuals (7T variant). RESULTS: The CFTR activity in airways and intestine was within the normal range. However both individuals presented with a borderline sweat test and the male patient was infertile. CONCLUSIONS: The lack of impact of the R117H mutation on chloride secretion in intestine and nose contrasts with the ~80% loss of CFTR activity reported in patch clamp studies. Apparently CFTR activity is not rate-limiting for chloride secretion in both tissues at levels >20% of normal, or compensatory factors may operate that are absent in heterologous host cells in vitro.

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120 In addition, the normal bioelectrical phenotype in the nasal epithelium of the R117H homozygous subjects contrasts with the elevated sodium absorption and minimal Cl-conductance reported in NPD measurements for CF patients carrying the A455E mutation [22]. Login to comment
128 5R.A. CBAVD in males [24], have distinct effects on the bioelectrical phenotype of the airways, ranging from normal (R117H) to severe (A455E). Login to comment
133 The lack of an intestinal bioelectrical phenotype in both R117H homozygous individuals may likewise result from intestine-specific rescue mechanisms but is also readily explained by the known insensitivity of the intestinal current measurements to a partial loss of CFTR function [30-32]. Login to comment
136 The R117H (and the A455E) CFTR mutants may therefore behave as borderline cases in which the homozygous expression is associated with a normal ICM pattern (≥20% residual CFTR conductance) whereas compound heterozygotes carrying a second more severe mutation (e.g. F508del) show a more variable residual CFTR Cl- current in the intestine ranging from normal to severely reduced, but not absent [24,33]. Login to comment
116 In addition, the normal bioelectrical phenotype in the nasal epithelium of the R117H homozygous subjects contrasts with the elevated sodium absorption and minimal Cl- conductance reported in NPD measurements for CF patients carrying the A455E mutation [22]. Login to comment
124 CBAVD in males [24], have distinct effects on the bioelectrical phenotype of the airways, ranging from normal (R117H) to severe (A455E). Login to comment

[hide] Implementation of the first worldwide quality assu... Clin Chim Acta. 2011 Jul 15;412(15-16):1376-81. Epub 2011 Apr 14. Earley MC, Laxova A, Farrell PM, Driscoll-Dunn R, Cordovado S, Mogayzel PJ Jr, Konstan MW, Hannon WH
Implementation of the first worldwide quality assurance program for cystic fibrosis multiple mutation detection in population-based screening.
Clin Chim Acta. 2011 Jul 15;412(15-16):1376-81. Epub 2011 Apr 14., 2011-07-15 [PMID:21514289]

Abstract [show]
BACKGROUND: CDC's Newborn Screening Quality Assurance Program collaborated with several U.S. Cystic Fibrosis Care Centers to collect specimens for development of a molecular CFTR proficiency testing program using dried-blood spots for newborn screening laboratories. METHODS: Adult and adolescent patients or carriers donated whole blood that was aliquoted onto filter paper cards. Five blind-coded specimens were sent to participating newborn screening laboratories quarterly. Proficiency testing results were evaluated based on presumptive clinical assessment. Individual evaluations and summary reports were sent to each participating laboratory and technical consultations were offered if incorrect assessments were reported. RESULTS: The current CDC repository contains specimens with 39 different CFTR mutations. Up to 45 laboratories have participated in the program. Three years of data showed that correct assessments were reported 97.7% of the time overall when both mutations could be determined. Incorrect assessments that could have lead to a missed case occurred 0.9% of the time, and no information was reported 1.1% of the time due to sample failure. CONCLUSIONS: Results show that laboratories using molecular assays to detect CFTR mutations are performing satisfactorily. The programmatic results presented demonstrate the importance and complexity of providing proficiency testing for DNA-based assays.

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129 Allele Allele Allele Allele p.Gly85Glu G85E (0.26) p.Arg117His R117H (0.54) c.489+1 GNT 621+1 GNT (1.3) p.Phe508del F508del (66.31) p.Arg347Pro R347P (0.36) p.lle507del I507del (0.90) p.Gly551Asp G551D (1.93) c.2052delA 2184delA (0.15) c.1585-1 GNA 1717-1 GNA (0.44) p.Gly542X G542X (2.64) c.3528delC 3659delC (0.28) p.Asn1303Lys N1303K (1.27) p.Arg553X R553X (1.21) p.Arg560Thr R560T (0.30) p.Arg1162X R1162X (0.30) c.2657+5 GNA 2789+5 GNA (0.38) c.3717+12191 CNT 3849+10kbCNT (0.85) c.2988+1 GNA 3120+1 GNA (0.86) p.Trp1282X W1282X (2.20) p.Ala455Glu A455E (0.26) c.1766+1 GNA 1898+1 GNA (0.13) c.579+1 GNT 711+1 GNT (0.35) p.Arg334Trp R334W (0.37) c.54-5940 _273+10250del21kb CFTR dele2,3 p.Ser549Asn S549N (0.14) c.1584 GNA 1716 G→A c.2051_2052delAAinsG 2183AANG (0.1) c.3140-26ANG 3272-26ANG c.262_263delTT 394delTT p.Arg1066Cys R1066C (0.03) p.Arg1066His R1066H c.1022_1023insTC 1154insTC c.2989-1 GNA 3121-1 GNA c.(?_2989)_(3139_? Login to comment

[hide] Clinical outcomes in infants with cystic fibrosis ... Pediatr Pulmonol. 2011 Apr 29. doi: 10.1002/ppul.21475. Ren CL, Desai H, Platt M, Dixon M
Clinical outcomes in infants with cystic fibrosis transmembrane conductance regulator (CFTR) related metabolic syndrome.
Pediatr Pulmonol. 2011 Apr 29. doi: 10.1002/ppul.21475., 2011-04-29 [PMID:21538969]

Abstract [show]
An unavoidable outcome of cystic fibrosis newborn screening (CF NBS) programs is the detection of infants with an indeterminate diagnosis. The United States CF Foundation recently proposed the term cystic fibrosis transmembrane conductance regulator related metabolic syndrome (CRMS) to describe infants with elevated immunoreactive trypsinogen (IRT) on NBS who do not meet diagnostic criteria for CF. The objective of this study was to describe the clinical outcomes of infants with CRMS identified through an IRT/DNA algorithm. We reviewed the records of all infants with CRMS diagnosed at our CF Center from 2002 to 2010. We identified 12 infants, and compared them to 27 infants diagnosed with CF by NBS. Compared to CF patients, CRMS patients were more likely to be pancreatic sufficient as assessed by fecal elastase measurement (100% vs. 8%, P < 0.01). Their weight for age percentile was normal from birth. A positive oropharyngeal (OP) culture for Pseudomonas aeruginosa (Pa) was found in 25% of CRMS patients. One patient with the F508del/R117H/7T genotype was reassigned the diagnosis of CF after he had a positive OP culture for Pa, and his follow up sweat Cl at 1 year of life was 73 mmol/L. CF patients were more likely to receive oral antibiotics and be hospitalized for pulmonary symptoms. Our results indicate that CRMS patients can develop signs of CF disease, but have a milder clinical course than CF infants. Close initial monitoring of these patients is warranted. Pediatr. Pulmonol. (c) 2011 Wiley-Liss, Inc.

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60 Infants in both groups received treatment with inhaled tobramycin if they had a positive Pa OP culture, and treatment in both groups was associated with eradication of TABLE 1-CFTR Gene Mutation Panel Used by New York CF NBS Program F508del I50e7del G542X G551D W1282X N1303K R553X 621þ1G>T R117H 1717-1G>A A455E R560T R1162X G85E R334W R347P 711þ1G>T 1898þ1G>A 2184delA 1078delT 3849þ10kbC>T 2789þ5G>A 3659delC I148T 3120þ1G>A 3876delA V520F S549R S549N 3849þ4 A-G 3905insT R347H Reflex testing for 5T polymorphism is performed if R117H is detected. Login to comment
61 Infants in both groups received treatment with inhaled tobramycin if they had a positive Pa OP culture, and treatment in both groups was associated with eradication of TABLE 1- CFTR Gene Mutation Panel Used by New York CF NBS Program F508del I50e7del G542X G551D W1282X N1303K R553X 621þ1G>T R117H 1717-1G>A A455E R560T R1162X G85E R334W R347P 711þ1G>T 1898þ1G>A 2184delA 1078delT 3849þ10kbC>T 2789þ5G>A 3659delC I148T 3120þ1G>A 3876delA V520F S549R S549N 3849þ4 A-G 3905insT R347H Reflex testing for 5T polymorphism is performed if R117H is detected. Login to comment

[hide] Pharmacological therapy for cystic fibrosis: from ... J Cyst Fibros. 2011 Jun;10 Suppl 2:S129-45. Becq F, Mall MA, Sheppard DN, Conese M, Zegarra-Moran O
Pharmacological therapy for cystic fibrosis: from bench to bedside.
J Cyst Fibros. 2011 Jun;10 Suppl 2:S129-45., [PMID:21658632]

Abstract [show]
With knowledge of the molecular behaviour of the cystic fibrosis transmembrane conductance regulator (CFTR), its physiological role and dysfunction in cystic fibrosis (CF), therapeutic strategies are now being developed that target the root cause of CF rather than disease symptoms. Here, we review progress towards the development of rational new therapies for CF. We highlight the discovery of small molecules that rescue the cell surface expression and defective channel gating of CF mutants, termed CFTR correctors and CFTR potentiators, respectively. We draw attention to alternative approaches to restore epithelial ion transport to CF epithelia, including inhibitors of the epithelial Na(+) channel (ENaC) and activators of the Ca(2+)-activated Cl(-) channel TMEM16A. The expertise required to translate small molecules identified in the laboratory to drugs for CF patients depends on our ability to coordinate drug development at an international level and our ability to provide pertinent biological information using suitable disease models.

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56 Interestingly, Zielenski and Tsui [10] assigned A455E and P574H, two CF mutations associated with a milder clinical phenotype (pancreatic sufficiency) to Class V. Login to comment
58 Moreover, on reaching the cell surface A455E forms Cl-channels with open probability (Po), a measure of channel activity, similar to that of wild-type CFTR, whereas the Po of P574H exceeds that of wild-type CFTR [15]. Login to comment

[hide] Recommendations for the classification of diseases... J Cyst Fibros. 2011 Jun;10 Suppl 2:S86-102. Bombieri C, Claustres M, De Boeck K, Derichs N, Dodge J, Girodon E, Sermet I, Schwarz M, Tzetis M, Wilschanski M, Bareil C, Bilton D, Castellani C, Cuppens H, Cutting GR, Drevinek P, Farrell P, Elborn JS, Jarvi K, Kerem B, Kerem E, Knowles M, Macek M Jr, Munck A, Radojkovic D, Seia M, Sheppard DN, Southern KW, Stuhrmann M, Tullis E, Zielenski J, Pignatti PF, Ferec C
Recommendations for the classification of diseases as CFTR-related disorders.
J Cyst Fibros. 2011 Jun;10 Suppl 2:S86-102., [PMID:21658649]

Abstract [show]
Several diseases have been clinically or genetically related to cystic fibrosis (CF), but a consensus definition is lacking. Here, we present a proposal for consensus guidelines on cystic fibrosis transmembrane conductance regulator (CFTR)-related disorders (CFTR-RDs), reached after expert discussion and two dedicated workshops. A CFTR-RD may be defined as "a clinical entity associated with CFTR dysfunction that does not fulfil diagnostic criteria for CF". The utility of sweat testing, mutation analysis, nasal potential difference, and/or intestinal current measurement for the differential diagnosis of CF and CFTR-RD is discussed. Algorithms which use genetic and functional diagnostic tests to distinguish CF and CFTR-RDs are presented. According to present knowledge, congenital bilateral absence of vas deferens (CBAVD), acute recurrent or chronic pancreatitis and disseminated bronchiectasis, all with CFTR dysfunction, are CFTR-RDs.

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323 Using biochemical (N) and functional (i and Po) data, the apical CFTR Cl- current generated by the CF-PI mutant p.F508del-CFTR and the CF-PS mutants p.R117H-, p.R334W-, p.R347P-, p.A455E- and p.P574H-CFTR were predicted [166,167]. Login to comment

[hide] Screening of DeltaF508 mutation and IVS8-poly T po... Andrologia. 2011 Jul 18. doi: 10.1111/j.1439-0272.2011.01193.x. Ghorbel M, Baklouti-Gargouri S, Keskes R, Sellami-Ben Hamida A, Feki-Chakroun N, Bahloul A, Fakhfakh F, Ammar-Keskes L
Screening of DeltaF508 mutation and IVS8-poly T polymorphism in CFTR gene in Tunisian infertile men without CBAVD.
Andrologia. 2011 Jul 18. doi: 10.1111/j.1439-0272.2011.01193.x., 2011-07-18 [PMID:21762191]

Abstract [show]
It is well established that cystic fibrosis transmembrane conductance regulator gene (CFTR) mutations are involved in congenital bilateral absence of the vas deferens (CBAVD), causing obstructive azoospermia and male infertility. Also, several studies reported a relatively high prevalence of CFTR gene mutations in healthy men presenting reduced sperm quality. In this study, we investigate DeltaF508 mutation and IVS8-polyT polymorphism in CFTR gene in Tunisian infertile men without CBAVD. Genetic analyses were performed in 148 infertile patients and 126 fertile individuals. The polymorphic IVS8-polyT tract in CFTR gene was analysed in only 129 infertile patients and 54 individuals of control group. As well, we screened for Y chromosome microdeletions in all infertile patients. No DeltaF508 mutation was diagnosed either in infertile patients or in control group. 5T allele of IVS8-polyT tract was found in both infertile men (4.26%) and fertile individuals (8.33%). 5T/5T genotype was observed only in two azoospermic patients without Y microdeletions. The most frequent genotype of IVS8-polyT tract in infertile men and controls was 7T/7T (69.75% and 59.25% respectively). There was no association between IVS8-polyT polymorphism and reduced semen quality. Neither DeltaF508 mutation nor 5T allele is involved in pathogenesis of male infertility in Tunisian infertile patients without CBAVD.

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91 Table 2 Genotype frequencies of IVS8-polyT tract variants in infertile men and controls IVS8-polyT genotype frequencies (%) 5T/5T 7T/7T 9T/9T All infertile patients (n = 129) 1.55 69.76 4.65 Azoospermia (n = 57) 3.50 73.68 5.26 Oligospermia (n = 39) 0 71.79 5.12 Normospermia (n = 33) 0 60.60 3.03 Controls (n = 54) 0 59.25 3.70 Table 3 Microdeleted STSs and IVS8-polyT genotype in patients with Y chromosome microdeletions (n = 7) Number of microdeleted patients Y chromosome microdeleted AZF loci and STSs IVS8-polyT genotype in CFTR gene Azoospermia (n = 57) 1 AZFa (SY86) 9T/9T 1 AZFa (SY84) 7T/7T Oligospermia (n = 48) 1 AZFa (SY86) 9T/9T 1 AZFa (SY86) 7T/7T 1 AZFa (SY84) 7T/7T 1 AZFa + b (SY86 + SY134) 7T/7T Normospermia (n = 43) 1 AZFc (SY254) 7T/7T patients (Boucher et al., 1999); it also agrees with data reported by Tuerlings et al. (1998) showing no increase in 5T allele and in three frequent CFTR mutations (deltaF508, A455E and G542X) among patients with oligozoospermia. Login to comment

[hide] Congenital bilateral absence of vas deferens with ... Clin Genet. 1998 Mar;53(3):202-4. Arduino C, Ferrone M, Brusco A, Garnerone S, Fontana D, Rolle L, Carbonara AO
Congenital bilateral absence of vas deferens with a new missense mutation (P499A) in the CFTR gene.
Clin Genet. 1998 Mar;53(3):202-4., [PMID:9630075]

Abstract [show]
We describe a congenital bilateral absence of the vas deferens (CBAVD) patient with a compound heterozygosity in the cystic fibrosis transmembrane regulator (CFTR) gene for a stop mutation W1282X and a new missense mutation P499A. The P499A is interpreted as a mild mutation whose phenotypic effects, in this case limited to the development of wolffian duct derivatives, are revealed only in combination with a severe CFTR mutation.

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52 Other missense mutations in this domain (A455E, P574H, G576A, S549N) have been found associated with a mild CF phenotype and their functional analysis in transfected cells revealed a low transport efficiency of the chloride channel and a reduced protein expression at the apical cell surface, which can explain the mild clinical phenotype (6). Login to comment

[hide] Pathology of pancreatic and intestinal disorders i... J R Soc Med. 1998;91 Suppl 34:40-9. Wilschanski M, Durie PR
Pathology of pancreatic and intestinal disorders in cystic fibrosis.
J R Soc Med. 1998;91 Suppl 34:40-9., [PMID:9709387]

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97 Molecular consequences of cftr gene mutations Several classification systems have been developed in an attempt to define the large number of cftr gene mutations on 43 I =ON 4o0 o 00 4O0 40 40 I II 111 IV V Normal NOmAfl Missnso G542X Missmnse Missense Missense A455E Fremeshift AA dIeIIOn 05510 R117H Allerndve 39soTT AF508 spiRlng Spl$oeJunculon 3849t10kbC4T1717-1G-4A Figure 4 Molecular consequences of cystic fibrosis transmembrane conductance regulator mutations. Login to comment
119 Class V mutations result in reduced synthesis of normal functioning CFTR due to defective processing (A455E) or aberrant splicing at alternative sites (3849+10kbC-T). Login to comment
152 A small number of more Table 1 Classification of cystic fibrosis gene mutation as severe, mild or indeterminate with respect to pancreatic function Severe Mild Variable (classes 1, I/ or 111) (classes IV or V) (classes IV or V) AF508 R117H G85E 1148T R334W 2789+5G-*A G480C R347P G551D A455E R560T P574H N1303K 3849+1 Okb C-+T G542X G551S W1282X P5748 621 +1 G-T R352Q 1717-1G-T T3381 556delA Adapted from Ref 20 with permission recently described mutations [G85E and 278+5G-÷AI are less clearly determinant with respect to the pancreatic sufficient and pancreatic insufficient phenotypes. Login to comment

[hide] Relation between mutations of the cystic fibrosis ... N Engl J Med. 1998 Sep 3;339(10):653-8. Cohn JA, Friedman KJ, Noone PG, Knowles MR, Silverman LM, Jowell PS
Relation between mutations of the cystic fibrosis gene and idiopathic pancreatitis.
N Engl J Med. 1998 Sep 3;339(10):653-8., 1998-09-03 [PMID:9725922]

Abstract [show]
BACKGROUND: It is unknown whether genetic factors predispose patients to idiopathic pancreatitis. In patients with cystic fibrosis, mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene typically cause pulmonary and pancreatic insufficiency while rarely causing pancreatitis. We examined whether idiopathic pancreatitis is associated with CFTR mutations in persons who do not have lung disease of cystic fibrosis. METHODS: We studied 27 patients (mean age at diagnosis, 36 years), 22 of whom were female, who had been referred for an evaluation of idiopathic pancreatitis. DNA was tested for 17 CFTR mutations and for the 5T allele in intron 8 of the CFTR gene. The 5T allele reduces the level of functional CFTR and is associated with an inherited form of infertility in males. Patients with two abnormal CFTR alleles were further evaluated for unrecognized cystic fibrosis-related lung disease, and both base-line and CFTR-mediated ion transport were measured in the nasal mucosa. RESULTS: Ten patients with idiopathic chronic pancreatitis (37 percent) had at least one abnormal CFTR allele. Eight CFTR mutations were detected (prevalence ratio, 11:1; 95 percent confidence interval, 5 to 23; P<0.001). In three patients both alleles were affected (prevalence ratio, 80:1; 95 percent confidence interval, 17 to 379; P<0.001). These three patients did not have lung disease typical of cystic fibrosis on the basis of sweat testing, spirometry, or base-line nasal potential-difference measurements. Nonetheless, each had abnormal nasal cyclic AMP-mediated chloride transport. CONCLUSION: In a group of patients referred for evaluation of idiopathic pancreatitis, there was a strong association between mutations in the CFTR gene and pancreatitis. The abnormal CFTR genotypes in these patients with pancreatitis resemble those associated with male infertility.

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34 Pancreatograms were assessed for the severity of chronic pancreatitis according to published criteria by a reviewer who was unaware of the patients` histories (Table 1).19 DNA Studies We extracted DNA from blood samples20 and tested for 16 CFTR mutations - ∆F508, W1282X, R117H, 621+1(G→T), R334W, R347P, A455E, ∆I507, 1717¡1(G→A), G542X, S549N, G551D, R553X, R560T, N1303K, and 3849+10Kb(C→T) - using reverse dot blot strips (Roche Molecular Systems, Alameda, Calif.). Login to comment

[hide] Detection of more than 91% cystic fibrosis mutatio... Clin Genet. 1998 Nov;54(5):437-9. Cartault F, Steffann J, Vidaud D, Bousquet S, Lesure F, Renouil M, McDonell N, Feingold J, Beldjord C, Bienvenu T
Detection of more than 91% cystic fibrosis mutations in a sample of the population from Reunion Island and identification of two novel mutations (A309G, S1255L) and one novel polymorphism (L49L)
Clin Genet. 1998 Nov;54(5):437-9., [PMID:9842999]

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15 Five have a frequency of 1% and above: AF508 (51%), Y122X (22.4%), 3120+ lG+A (7.7%), A455E (2.1%) and G551D (1.4%). Login to comment
26 The A455E has only been reported rarely in CF patients; its frequencyis higher than 1%in only two regions, in the Netherlands and in Saguenay Lac-Saint-Jean. Login to comment
30 Ten CFTR mutations identified in 69 CF families from Reunion Island Mutationa Exonlintron CF alleles Percentage Ama E.10 72 52 Y122X E.4 33 24 A455E E.9 3 2.2 G551D E.11 2 1.4 1717-1G-+A i.10 1 0.7 G542X E.ll 1 0.7 116ldelC E.7 1 0.7 A3G9G E.7 1 0.7 zag+ 5~-+A i.14b 1 0.7 3120tlG-A i.16 11 a Unknown mutations 12 8.7 aCystic Fibrosis Genetic Analysis Consortium: Web site: http // w.genet.sickkids.on.ca/cftr/ CFTR represents the missense mutation A309G (Fig. 1A). Login to comment

[hide] Chronic pancreatitis and mutations of the cystic f... Gut. 1999 Jan;44(1):8-9. Taylor CJ
Chronic pancreatitis and mutations of the cystic fibrosis gene.
Gut. 1999 Jan;44(1):8-9., [PMID:9862818]

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61 Reproduced with permission from Wilschanski et al.2 V Missense A455E Alternative splicing 3849+10kbC (f) IV Missense R117H (e) III Missense G551D (d) II Missense AA deletion ∆F508 (c) I Nonsense G542X Frameshift 394delTT Splice junction 1717-1G (b) Normal (a) T A Chronic pancreatitis and mutations of the cyctic fibrosis gene group.bmj.comon August 8, 2011 - Published bygut.bmj.comDownloaded from doi: 10.1136/gut.44.1.8 1999 44: 8-9Gut C J TAYLOR cystic fibrosis gene Chronic pancreatitis and mutations of the http://gut.bmj.com/content/44/1/8.full.html Updated information and services can be found at: These include: References http://gut.bmj.com/content/44/1/8.full.html#related-urls Article cited in: http://gut.bmj.com/content/44/1/8.full.html#ref-list-1 This article cites 4 articles, 2 of which can be accessed free at: service Email alerting box at the top right corner of the online article. Login to comment

[hide] Relationships between nasal potential difference a... Eur Respir J. 1998 Dec;12(6):1295-300. Fajac I, Hubert D, Bienvenu T, Richaud-Thiriez B, Matran R, Kaplan JC, Dall'Ava-Santucci J, Dusser DJ
Relationships between nasal potential difference and respiratory function in adults with cystic fibrosis.
Eur Respir J. 1998 Dec;12(6):1295-300., [PMID:9877480]

Abstract [show]
This study investigated the relations between nasal transepithelial electric potential difference (PD) and the phenotype and genotype of cystic fibrosis (CF) adult patients. Basal nasal PD was measured in 95 adult CF patients who were classified into three groups of nasal PD (expressed as absolute values) according to the 10th and the 90th percentiles (28.3 and 49.2 mV, respectively), which defined group 1 (nasal PD < or =28.3 mV), group 2 (nasal PD 28.3-49.2 mV) and group 3 (nasal PD > or =49.2 mV). Patients from group 1 had a higher forced vital capacity (FVC) than patients from groups 2 and 3 (76.5+/-22.4 versus 57.4+/-21.2 and 55.7+/-21.1% predicted, respectively, p<0.05) and a higher forced expiratory volume in one second (FEV1) (69.3+/-24.0 versus 42.5+/-22.4 and 42.2+/-21.4% pred, respectively, p<0.01). Among patients with severe mutations (deltaF508 homozygotes, or one deltaF508 mutation plus another "severe" mutation, or two "severe" mutations), patients from group 1 had a higher FVC, FEV1 and arterial oxygen tension than patients from groups 2 and 3 (p<0.05 for each comparison). The results show that in adult cystic fibrosis patients a normal basal nasal potential difference is related to milder respiratory disease, irrespective of the severity of the genotype.

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148 In five CF patients carrying the A455E mutation associated with mild pulmonary disease, severe defects in airway bioelectrical properties were found [10]. Login to comment

[hide] Mutations of the cystic fibrosis gene and pancreat... N Engl J Med. 1999 Jan 21;340(3):238-9. Ren CL
Mutations of the cystic fibrosis gene and pancreatitis.
N Engl J Med. 1999 Jan 21;340(3):238-9., 1999-01-21 [PMID:9917235]

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217 If CFTR mutations affect the sweat ducts, the function of CFTR in the lung will also be affected.4 The DF508/A455E genotype in particular is associated with elevated sweat chloride concentrations and delayed onset of pulmonary disease4 ; Sharer et al. did not screen for this mutation. Login to comment
231 An abnormal nasal potential difference is arguably a more reliable demonstrator of CFTR function than sweat testing,2 and indeed, patients with the 3849+10Kb (C→T) mutation may have normal sweat chloride concentrations but abnormal nasal-potential-difference properties.3 We did not test for the A455E mutation, since it does not seem to occur in our population.4 This mutation is associated with mild pulmonary disease, pancreatic sufficiency, and as far as we are aware, normal glucose tolerance.5 In our study, Patients 9 and 15 both had pancreatic insufficiency, with the latter also having insulin-dependent diabetes mellitus. Login to comment

[hide] CFTR is a conductance regulator as well as a chlor... Physiol Rev. 1999 Jan;79(1 Suppl):S145-66. Schwiebert EM, Benos DJ, Egan ME, Stutts MJ, Guggino WB
CFTR is a conductance regulator as well as a chloride channel.
Physiol Rev. 1999 Jan;79(1 Suppl):S145-66., [PMID:9922379]

Abstract [show]
CFTR Is a Conductance Regulator as well as a Chloride Channel. Physiol. Rev. 79, Suppl.: S145-S166, 1999. - Cystic fibrosis transmembrane conductance regulator (CFTR) is a member of the ATP-binding cassette (ABC) transporter gene family. Although CFTR has the structure of a transporter that transports substrates across the membrane in a nonconductive manner, CFTR also has the intrinsic ability to conduct Cl- at much higher rates, a function unique to CFTR among this family of ABC transporters. Because Cl- transport was shown to be lost in cystic fibrosis (CF) epithelia long before the cloning of the CF gene and CFTR, CFTR Cl- channel function was considered to be paramount. Another equally valid perspective of CFTR, however, derives from its membership in a family of transporters that transports a multitude of different substances from chemotherapeutic drugs, to amino acids, to glutathione conjugates, to small peptides in a nonconductive manner. Moreover, at least two members of this ABC transporter family (mdr-1, SUR) can regulate other ion channels in the membrane. More simply, ABC transporters can regulate somehow the function of other cellular proteins or cellular functions. This review focuses on a plethora of studies showing that CFTR also regulates other ion channel proteins. It is the hope of the authors that the reader will take with him or her the message that CFTR is a conductance regulator as well as a Cl- channel.

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108 A''half molecule`` of CFTR (TNR-CFTR) in which amino acids 836 through 1480 were eliminated (TMD-1, NBD1, mild mutation within NBD1, A455E, caused a small reduction in Cl0 channel function but did not affect cAMP stim-and R domains of CFTR intact) functioned in oocytes as a 9-pS single Cl0 channel similar to wild-type CFTR. Login to comment

[hide] Adenosine and its nucleotides activate wild-type a... Am J Physiol. 1999 Feb;276(2 Pt 1):C361-9. Clancy JP, Ruiz FE, Sorscher EJ
Adenosine and its nucleotides activate wild-type and R117H CFTR through an A2B receptor-coupled pathway.
Am J Physiol. 1999 Feb;276(2 Pt 1):C361-9., [PMID:9950763]

Abstract [show]
ATP and its metabolites stimulate Cl- secretion in human epithelium in vitro and in vivo. The specific purinergic receptor subtypes that govern these effects have been difficult to separate, in part due to multiple parallel pathways for Cl- secretion in respiratory and intestinal epithelia. In a simplified model using COS-7 cells, we demonstrate acquisition of an ATP-, ADP-, AMP-, and adenosine (ADO)-regulated halide permeability specifically following expression of wild-type (wt) cystic fibrosis transmembrane conductance regulator (CFTR). This halide permeability is blocked by the P1 purinergic receptor antagonist 8-phenyl theophylline, sensitive to the protein kinase A inhibitor H-89, and associated with a modest, dose-dependent increase in cellular cAMP concentration. Phorbol esters poorly activate halide permeability compared with ADO, and ADO-stimulated efflux was not affected by treatment with the protein kinase C inhibitor bisindolylmaleimide I. The A2 ADO receptor (AR) agonists 5'-N-ethylcarboxamide adenosine and ADO were strong activators, whereas the A1 AR agonist R-phenylisopropyladenosine failed to activate halide permeability. Metabolic conversion of ADO nucleotides by surface ecto-5'-nucleotidase to more active (less phosphorylated) forms contributes to anion transport activation in these cells. Immunoprecipitation with anti-A2B AR antibody identified a 31-kDa protein in both COS-7 and human bronchial epithelial cells. Together, these findings indicate that ADO and its nucleotides are capable of activating wtCFTR-dependent halide permeability through A2B AR and that this AR subtype is present in human bronchial epithelium. We also present data showing that this pathway can activate clinically significant mutant CFTR molecules such as R117H.

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251 For example, additional experiments in COS-7 cells have recently allowed us to identify two other surface-localized CFTR mutants (A455E and G1349D) that can functionally couple to A2B AR activation (11). Login to comment

[hide] Outcomes of a cystic fibrosis carrier testing clin... Med J Aust. 2009 Nov 2;191(9):499-501. Christie LM, Ingrey AJ, Turner GM, Proos AL, Watts GE
Outcomes of a cystic fibrosis carrier testing clinic for couples.
Med J Aust. 2009 Nov 2;191(9):499-501., 2009-11-02 [PMID:19883345]

Abstract [show]
OBJECTIVE: To review the outcomes of offering carrier testing for cystic fibrosis (CF) to couples considering pregnancy, and to women in early pregnancy and their partners. METHODS: An after-hours clinic was established in Newcastle for discussion of issues related to prenatal testing. Couples were offered CF carrier testing by extracting DNA from a mouthwash sample. An expanded one-step model was used with both partners being tested initially for the p.F508del cystic fibrosis transmembrane conductance regulator gene (CFTR) mutation. If one partner was a p.F508del carrier, the other partner was tested for an additional 28 CFTR mutations. RESULTS: Of 1000 individuals who were offered CF carrier testing, none declined. No re-collections of mouthwash samples were required, and results were available within 14 days. There were 730 individuals who had no family history of CF (73%); 27 were carriers (4%; 95% CI, 2.4%-5.3%), and there were two high-risk couples where both partners were carriers of p.F508del. There were 270 individuals who had an affected family member with CF or a child identified as a CF carrier through newborn screening; 126 were carriers (46%; 95% CI, 40.6%-52.8%), and there were two high-risk couples - one couple where both partners were carriers of p.F508del, and another couple where the woman was homozygous for p.F508del and the man was a p.F508del carrier. The information on carrier status led the four high-risk couples to change their reproductive decisions to avoid having a child with CF. CONCLUSION: CF carrier testing for couples using an expanded one-step model will detect about 80% of high-risk couples and enables various reproductive choices. We believe that all couples considering pregnancy, and women in early pregnancy and their partners, should be offered CF carrier testing.

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72 This provides each individual with information on their carrier status, and accurate residual risks of 1 CFTR mutations tested for in individuals whose partner was a carrier of p.F508del* p.F508del p.F316leufsX p.I507del p.R347P p.G542X p.S1251N p.G551D p.E60X p.N1303K p.W1282X c.1585-1G>A p.D1152H p.R553X c.2988+1G>A c.489+G>T c.2657+5G>A p.R117H c.1766+1G>A p.R1162X c.579+1G>A c.3717+10kbC>T p.G85E p.R334W p.K684fs p.A455E p.I148T p.K684fs p.R560T p.T1176fs CFTR = gene encoding cystic fibrosis transmembrane conductance regulator. Login to comment

[hide] Cystic fibrosis in Chilean patients: Analysis of 3... J Cyst Fibros. 2011 Jan;10(1):66-70. Epub 2010 Oct 30. Lay-Son G, Puga A, Astudillo P, Repetto GM
Cystic fibrosis in Chilean patients: Analysis of 36 common CFTR gene mutations.
J Cyst Fibros. 2011 Jan;10(1):66-70. Epub 2010 Oct 30., [PMID:21036675]

Abstract [show]
BACKGROUND: CFTR gene mutations have worldwide differences in prevalence and data on Chilean patients is scarce. METHODS: We studied 36 of the most common CFTR mutations in Chilean patients from the CF National Program [Programa Nacional de Fibrosis Quistica (PNFQ)] of the Ministry of Health of Chile. RESULTS: Two hundred and eighty-nine patients were studied. Fourteen different mutations were identified with an overall allele detection rate of 42.0%. Mutations with frequencies greater than 1% were p.F508del (30.3% of alleles), p.R334W (3.3%), p.G542X (2.4%), c.3849+10Kb C>T (1.7%), and p.R553X (1.2%). A north to south geographical gradient was observed in the overall rate of detection. CONCLUSIONS: Southern European CFTR mutations predominate in the Chilean population, but a high percentage of alleles remain unknown. Geographical heterogeneity could be explained in part by admixture. Complementary analyses are necessary to allow for effective genetic counselling and improve cost-effectiveness of screening and diagnostic tests.

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50 Seven mutations had not been previously reported in the Chilean population (p.1078delT, pG85E, c.3120+1 GNA, c.711+1 GNT, p.R117H, p.A455E, and p.I148T). Login to comment
81 Mutation This study Rios et al. [4] Molina et al. [5] Repetto et al. [6] Perez et al. [13] CFGAC [2] (n=578) (%) (n=72) (%) (n=36) (%) (n=100) (%) (n=4102) (%) (n=43,849) (%) Chile Chile Chile Chile Latin-Americaa Worldwide Unknown 58.0 66.6 61.1 34.0 36.7 22.7 p.F508del 30.6 29.2 30.6 45.0 47.1 66.0 p.R334W 3.1 - - 2.0 0.8 0.1 p.G542X 2.4 0 8.3 7.0 5.0 2.4 c.3849+10Kb CNT 1.7 - - 3.0 0.3 0.2 p.R553X 1.2 4.2 0 1.0 0.4 0.7 p.R1162X 0.9 - - 2.0 1.0 0.3 p.1078delT 0.5 - - 0 b0.1 0.1 p.G85E 0.5 - - - 0.8 0.2 p.W1282X 0.2 - - 5.0 1.0 1.2 c.3120+1 GNA 0.2 - - - 0.3 - c.711+1 GNT 0.2 - - - 0.1 0.1 p.R117H 0.2 - - 0 b0.1 0.3 p.A455E 0.2 - - 0 0 0.1 p.I148T 0.2 - - - - - p.G551D 0 0 0 1.0 0.1 1.6 p.N1303K 0 0 0 0 1.8 1.3 c.621+1 GNT 0 - - 0 0.2 0.7 c.1717-1 GNA 0 - - 0 0.3 0.6 p.I507del 0 - - 0 0.2 0.2 p.R347P 0 - - 0 0 0.2 c.2789+5 GNA 0 - - - 0.2 0.1 c.1898+1 GNA 0 - - - 0.1 0.1 c.2184delA 0 - - - b0.1 0.1 p.S549N 0 - 0 - 0.1 0.1 c.3659delC 0 - - 0 0.1 0.1 p.R560T 0 - - - 0 0.1 c.1811+1.6Kb ANG 0 - - - 0.4 - c.2183AANG 0 - - 0 0.1 - p.S549R 0 - - - 0.1 - c.3272-26 ANG 0 - - - 0.1 - c.3199del6 0 - - - b0.1 - p.E60X 0 - - 0 0 - c.3905insT 0 - - - 0 - p.S1251N 0 - - 0 - - CFTRdele2,3 0 - - - - - p.R347H 0 - - - - - p.V520F 0 - - - - - p.Q552X 0 - - - - - c.394delTT 0 - - - - - c.711+1 GNA 0 - - - - - c.2143delT 0 - - - - - c.3876delA 0 - - - - - a Data from Chilean patients published in Rios et al., Molina et al., and Repetto et al. [4-6] included in this publication were excluded in this table to avoid repetition. Login to comment

[hide] Quantitative expression patterns of multidrug-resi... Eur J Biochem. 1992 May 15;206(1):137-49. Bremer S, Hoof T, Wilke M, Busche R, Scholte B, Riordan JR, Maass G, Tummler B
Quantitative expression patterns of multidrug-resistance P-glycoprotein (MDR1) and differentially spliced cystic-fibrosis transmembrane-conductance regulator mRNA transcripts in human epithelia.
Eur J Biochem. 1992 May 15;206(1):137-49., [PMID:1375156]

Abstract [show]
P-glycoprotein (MDR1), that confers multidrug resistance in cancer, and the cystic-fibrosis transmembrane-conductance regulator (CFTR), that is causative defective in cystic fibrosis, belong to the family of ATP-binding transport proteins. The expression of MDR1 and CFTR in human epithelial tissues and the cell lines T84 and HT29 was estimated by primer-directed reverse transcription (RT) and subsequent monitoring of the kinetics of cDNA product formation during the polymerase chain reaction (PCR). MDR1 mRNA was found in high levels, 15-50 amol mRNA/microgram RNA, in the intestine, kidney, liver and placenta, and in low levels, 0.2 amol/microgram RNA, in respiratory epithelium. Large amounts of CFTR mRNA were measured in the gastrointestinal tract, whereas the kidney, as the phenotypically normal organ, and the lung, as the most severely affected organ in cystic fibrosis, both contained low amounts, 3 amol CFTR/microgram RNA. CFTR transcript levels of 1-5 amol/microgram RNA were determined in lymphocytes and lymphoblast cell lines, suggesting that lymphoblasts are an accessible source for the study of the molecular pathogenesis of cystic fibrosis. When transcripts were scanned by overlapping RT/PCR analyses, only transcript of expected size was detected for MDR1 mRNA, where variable in-frame deletions of either exon 4, 9 or 12 were observed in CFTR mRNA. The complete loss of single exons was seen at proportions of 1-40% in all investigated tissues and cell lines with large donor-to-donor variation. Exons 9 and 12 of the CFTR gene encode parts of the evolutionarily well-conserved first nucleotide-binding fold including the two Walker motifs. Alternative splicing may give rise to various CFTR forms of different function and localization.

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138 After screening for the Phe508 deletion (Kerem et al., 1989), most CFTR mutations were investigated by restriction analysis of PCR products (R334W, R347P, A455E, G551D, R553X, R1162X, W1282X) (Cutting et al., 1990; Dean et al., 1990; Gasparini et al., 1991; Kerem et al., 1990; Vidaud et al., 1990). Login to comment

[hide] Structure-function analysis of the histidine perme... J Biol Chem. 1991 Oct 5;266(28):18714-9. Shyamala V, Baichwal V, Beall E, Ames GF
Structure-function analysis of the histidine permease and comparison with cystic fibrosis mutations.
J Biol Chem. 1991 Oct 5;266(28):18714-9., [PMID:1717452]

Abstract [show]
Traffic ATPases constitute a superfamily of transporters that include prokaryotic permeases and medically important eukaryotic proteins, such as the multidrug resistance P-glycoprotein and the cystic fibrosis gene product. We present a structure-function analysis of a member of this superfamily, the prokaryotic histidine permease, using mutations generated both in vitro and in vivo, and assaying several biochemical functions. The analysis supports a previously predicted structural model and allows the assignment of specific functions to several predicted structural features. Mutations in the secondary structure features which form the nucleotide-binding pocket in general cause the loss of ATP binding activity. Mutations in the helical domain retain ATP binding activity. Several mutations have been identified which may affect the signaling mechanism between ATP hydrolysis and membrane translocation. We relate our findings to those emerging from the recent biochemical and genetic analyses of cystic fibrosis mutations.

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159 A few mutations are located in the nucleotide-binding pocket, A455E,G458V, and P574H, and may be tolerated because they may have maintained partial activity, especially the two that are not located insites defined as critical for ATP binding by the HisPanalysis. Login to comment

[hide] beta-Adrenergic Sweat Secretion as a Diagnostic Te... Am J Respir Crit Care Med. 2012 Oct 15;186(8):732-9. doi: 10.1164/rccm.201205-0922OC. Epub 2012 Aug 2. Quinton P, Molyneux L, Ip W, Dupuis A, Avolio J, Tullis E, Conrad D, Shamsuddin AK, Durie P, Gonska T
beta-Adrenergic Sweat Secretion as a Diagnostic Test for Cystic Fibrosis.
Am J Respir Crit Care Med. 2012 Oct 15;186(8):732-9. doi: 10.1164/rccm.201205-0922OC. Epub 2012 Aug 2., [PMID:22859523]

Abstract [show]
Rationale: beta-Adrenergically induced sweat secretion offers an expedient method to assess native cystic fibrosis transmembrane conductance regulator (CFTR) secretory function in vivo. Objectives: To evaluate the sensitivity, specificity, and reliability of a test based on the activity and secretory function of CFTR in the sweat gland. Methods: Primary and validation trials with prospectively ascertained healthy control subjects, obligate heterozygotes, and patients with a CFTR-related disorder and CF (pancreatic sufficient and insufficient). Measurements and Main Results: Diagnostic accuracy and reliability of beta-adrenergic sweat secretory rates using an evaporimeter was assessed and compared with sweat chloride concentrations. The cholinergically stimulated mean sweat rate did not differ among groups. The mean maximal beta-adrenergically stimulated sweat rate in heterozygotes was about half the rate of healthy control subjects, and completely absent in pancreatic-insufficient patients with CF and pancreatic-sufficient patients with CF (P < 0.0001). Subjects with a CFTR-related disorder showed reduced or absent beta-adrenergic sweat secretion. The beta-adrenergic secretory response demonstrated high diagnostic accuracy (area under a characteristic receiver-operator curve = 0.99; 95% confidence interval, 0.97-1.00) and reliability (intraclass correlation, 0.90; 95% confidence interval, 0.81-0.95). The diagnostic cutoff level for CF, derived from the primary trial, correctly identified all control subjects, heterozygotes, and patients with CF in the validation cohort, whereas concurrent sweat chloride measurements misclassified one heterozygote and five subjects with CF. The cholinergic and beta-adrenergic sweat secretion rates were lower in women compared with men (P < 0.001). Conclusions: beta-Adrenergic sweat secretion rate determined by evaporimetry is an accurate and reliable technique to assess different levels of CFTR function and to identify patients with CF.

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42 DIAGNOSTIC CHARACTERISTICS OF PARTICIPANTS IN THE VALIDATION COHORT Group Age (yr) Sex Genotype Sweat Cl2 (mmol/L) Cholinergic b-Adrenergic Ratio b/Chol Healthy 38 M 2/2 15 64.45 72.79 1.13 Healthy 39 M 2/2 18 81.61 86.08 1.05 Healthy 54 F 2/2 29 48.90 47.30 0.97 Healthy 64 F 2/2 28 50.64 57.54 1.14 Healthy 54 F 2/2 11 68.63 52.30 0.76 Hetero. 64 M F508del/2 16 68.21 36.78 0.54 Hetero. 56 M F508del/2 53 82.44 59.57 0.72 Hetero. 27 F F508del/2 11 78.30 46.30 0.59 Hetero. 29 F F508del/2 16 65.63 26.13 0.40 Hetero. 51 F G551D/2 62 39.13 16.50 0.42 CFTR-RD CBAVD 41 M W1282X/5T 55 84.61 20.69 20.01 CFTR-RD CBAVD 52 M F508del/R117H (7T) 57 70.39 20.61 20.01 CFTR-RD CBAVD 41 M F508del/5T 40 68.00 22.29 20.03 CFTR-RD CBAVD 47 M G551D/R117H (7T) 57 65.93 10.08 0.15 CFTR-RD CBAVD 40 M L206W/W216C 42 67.80 17.00 0.25 CFTR-RD CBAVD 26 M 36599delC15T/7T 55 91.55 0.18 0.00 CFTR-RD Sinopulm 65 F F508del/c.876-9_876-6delGATT 51 74.30 32.20 0.43 CFTR-RD Sinopulm 39 F R764X/2 12 24.64 3.49 0.14 CFTR-RD Sinopulm 17 F 5T/2 50 52.95 14.24 0.27 CFPS 21 M F508del/2 97 46.19 0.56 0.01 CFPS 33 M F508del/3849110kbC.T 50 76.22 22.94 20.04 CFPS 58 M 71111G.T/A455E 72 70.19 23.06 20.04 CFPS 41 M G551D/3849110kbC.T 88 87.37 0.08 0.00 CFPS 54 F F508del/R117C 59 36.74 1.06 0.03 CFPS 23 F F508del/A455E 82 64.85 3.46 0.05 CFPS 30 F D1152H/D1152H 31 41.52 23.54 20.09 CFPS 55 F G551D/2 99 67.62 21.78 20.03 CFPS 42 F F508del/1002-2A.G 94 27.64 2.63 0.10 CFPS 46 F 3849110kbC.T/3849110kbC.T 53 24.43 21.16 20.05 CFPS 14 F R1162X/3849110kbC.T 46 50.19 20.49 20.01 CFPI 32 M F508del/F508del 108 73.93 1.41 0.02 CFPI 28 M F508del/F508del 84 95.13 3.45 0.04 CFPI 24 F F508del/F508del 109 60.48 4.06 0.07 CFPI 34 F F508del/F508del 115 79.24 0.99 0.01 CFPI 35 F F508del/F508del 87 79.79 23.02 20.04 CFPI 44 F F508del/F508del 112 80.60 1.23 0.02 CFPI 23 F F508del/G551D 90 45.80 0.80 0.02 Definition of abbreviations: CBAVD ¼ congenital bilateral absence of vas deference; CF ¼ cystic fibrosis; CFPI ¼ pancreatic-insufficient patients with CF; CFPS ¼ pancreatic-sufficient patients with CF; CFTR ¼ CF transmembrane regulator; CFTR-RD ¼ CFTR-related disorder; hetero ¼ heterozygotes; sinopulm ¼ chronic sinopulmonary disease. Login to comment
43 DIAGNOSTIC CHARACTERISTICS OF PARTICIPANTS IN THE VALIDATION COHORT Group Age (yr) Sex Genotype Sweat Cl2 (mmol/L) Cholinergic b-Adrenergic Ratio b/Chol Healthy 38 M 2/2 15 64.45 72.79 1.13 Healthy 39 M 2/2 18 81.61 86.08 1.05 Healthy 54 F 2/2 29 48.90 47.30 0.97 Healthy 64 F 2/2 28 50.64 57.54 1.14 Healthy 54 F 2/2 11 68.63 52.30 0.76 Hetero. 64 M F508del/2 16 68.21 36.78 0.54 Hetero. 56 M F508del/2 53 82.44 59.57 0.72 Hetero. 27 F F508del/2 11 78.30 46.30 0.59 Hetero. 29 F F508del/2 16 65.63 26.13 0.40 Hetero. 51 F G551D/2 62 39.13 16.50 0.42 CFTR-RD CBAVD 41 M W1282X/5T 55 84.61 20.69 20.01 CFTR-RD CBAVD 52 M F508del/R117H (7T) 57 70.39 20.61 20.01 CFTR-RD CBAVD 41 M F508del/5T 40 68.00 22.29 20.03 CFTR-RD CBAVD 47 M G551D/R117H (7T) 57 65.93 10.08 0.15 CFTR-RD CBAVD 40 M L206W/W216C 42 67.80 17.00 0.25 CFTR-RD CBAVD 26 M 36599delC15T/7T 55 91.55 0.18 0.00 CFTR-RD Sinopulm 65 F F508del/c.876-9_876-6delGATT 51 74.30 32.20 0.43 CFTR-RD Sinopulm 39 F R764X/2 12 24.64 3.49 0.14 CFTR-RD Sinopulm 17 F 5T/2 50 52.95 14.24 0.27 CFPS 21 M F508del/2 97 46.19 0.56 0.01 CFPS 33 M F508del/3849110kbC.T 50 76.22 22.94 20.04 CFPS 58 M 71111G.T/A455E 72 70.19 23.06 20.04 CFPS 41 M G551D/3849110kbC.T 88 87.37 0.08 0.00 CFPS 54 F F508del/R117C 59 36.74 1.06 0.03 CFPS 23 F F508del/A455E 82 64.85 3.46 0.05 CFPS 30 F D1152H/D1152H 31 41.52 23.54 20.09 CFPS 55 F G551D/2 99 67.62 21.78 20.03 CFPS 42 F F508del/1002-2A.G 94 27.64 2.63 0.10 CFPS 46 F 3849110kbC.T/3849110kbC.T 53 24.43 21.16 20.05 CFPS 14 F R1162X/3849110kbC.T 46 50.19 20.49 20.01 CFPI 32 M F508del/F508del 108 73.93 1.41 0.02 CFPI 28 M F508del/F508del 84 95.13 3.45 0.04 CFPI 24 F F508del/F508del 109 60.48 4.06 0.07 CFPI 34 F F508del/F508del 115 79.24 0.99 0.01 CFPI 35 F F508del/F508del 87 79.79 23.02 20.04 CFPI 44 F F508del/F508del 112 80.60 1.23 0.02 CFPI 23 F F508del/G551D 90 45.80 0.80 0.02 Definition of abbreviations: CBAVD &#bc; congenital bilateral absence of vas deference; CF &#bc; cystic fibrosis; CFPI &#bc; pancreatic-insufficient patients with CF; CFPS &#bc; pancreatic-sufficient patients with CF; CFTR &#bc; CF transmembrane regulator; CFTR-RD &#bc; CFTR-related disorder; hetero &#bc; heterozygotes; sinopulm &#bc; chronic sinopulmonary disease. Login to comment

[hide] Management of male infertility due to congenital b... Andrologia. 2012 Oct;44(5):358-62. doi: 10.1111/j.1439-0272.2012.01288.x. Epub 2012 Mar 6. Grzegorczyk V, Rives N, Sibert L, Dominique S, Mace B
Management of male infertility due to congenital bilateral absence of vas deferens should not ignore the diagnosis of cystic fibrosis.
Andrologia. 2012 Oct;44(5):358-62. doi: 10.1111/j.1439-0272.2012.01288.x. Epub 2012 Mar 6., [PMID:22390181]

Abstract [show]
Microsurgical or percutaneous epididymal sperm aspiration and intracytoplasmic sperm injection (ICSI) are proposed to overcome male infertility due to congenital bilateral absence of vas deferens (CBAVD). CBAVD has been associated with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and consequently, genetic counselling has to be addressed before beginning ICSI procedure. However, management of male infertility due to CBAVD should not ignore a mild form of cystic fibrosis. We describe the case of cystic fibrosis late diagnosis performed in a 49-year-old infertile men with CBAVD. CFTR molecular testing detected two mutations F508del and A455E corresponding to a cystic fibrosis genotype. Pneumological evaluation revealed a severe obstructive respiratory disease, bronchiectasis and high sweat chloride levels. Symptoms consistent with a cystic fibrosis have to be identified in infertile men with CBAVD before beginning assisted reproductive procedures.

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6 CFTR molecular testing detected two mutations F508del and A455E corresponding to a cystic fibrosis genotype. Pneumological evaluation revealed a severe obstructive respiratory disease, bronchiectasis and high sweat chloride levels. Login to comment
29 CFTR molecular testing detected two mutations, F508del and A455E (Pr. C. Ferec, Brest University Hospital) corresponding to a CF genotype. Pneumological evaluation confirmed the diagnosis of CF with a severe obstructive respiratory disease, bronchiectasis and high sweat chloride levels. Login to comment
49 Some genotypes had been described in patients with moderate or late CF, such as those with F508del/L206W, F508del/D1152H, F508del/A455E like in our patient. Login to comment
51 A455E mutation is a missense mutation and belongs to class V mutation. Login to comment
54 A relationship has been described between the A455E mutation and milder lung disease in patients with CF. Login to comment
55 Patients with the A455E mutation had significantly better lung function and less pancreatic insufficiency than the F508del homozygotes (Gan et al., 1995) and are generally diagnosed at older age than matched F508del homozygotes. Login to comment
56 Mild symptoms of CF are most likely associated with the presence of A455E mutation because all of the A455E compound heterozygotes had a severe mutation in the second allele like our proband (Gan et al., 1995). Login to comment
57 These data were confirmed by De Braekeleer et al. (1997) who showed that pulmonary problems were the leading clinical feature at diagnosis with a mean sweat chloride concentration lower among the A455E heterozygotes. Login to comment
58 Moreover, a lower mortality rate was also reported in patients with F508del/ A455E than in F508del homozygotes (9.1% vs 21.2%) confirming the evidence that the A455E mutation is associated with a milder form of CF and a better prognosis. Login to comment

[hide] Report on the p.Ser489X (p.Ser489*) CFTR mutation,... Genet Med. 2012 Oct;14(10):883-6. doi: 10.1038/gim.2012.57. Epub 2012 May 24. De Bie I, Agatep R, Scott P, Ruchon A
Report on the p.Ser489X (p.Ser489*) CFTR mutation, a variant with severe associated phenotype and high prevalence in a Quebec French-Canadian cystic fibrosis patient population.
Genet Med. 2012 Oct;14(10):883-6. doi: 10.1038/gim.2012.57. Epub 2012 May 24., [PMID:22627569]

Abstract [show]
Purpose:This study reports on the phenotype of cystic fibrosis patients identified to be carriers of the p.Ser489X (p.Ser489*; c.1466C>A) cystic fibrosis transmembrane conductance regulator (CFTR) mutation, a variant rarely described in the cystic fibrosis literature, as well as on its allelic frequency in a French-Canadian cystic fibrosis patient cohort.Methods:Reported phenotypes and allelic frequency of this variant were collected based on the data from a large French-Canadian cystic fibrosis patient cohort.Results:Cystic fibrosis patients found to carry the p.Ser489X variant generally presented with classic gastrointestinal manifestations of this condition in infancy. The allelic frequency of this variant was calculated to be 0.7% for this population.Conclusion:The p.Ser489X CFTR variant is a severe disease-causing CFTR allele that is relatively frequent in the French-Canadian cystic fibrosis patient population, warranting its inclusion into CFTR molecular testing panel for this population.Genet Med 2012:14(10):883-886.

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4 In this population, three Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations account for ~94% of disease alleles, namely p.Phe508del (p.F508del; [delta] F508, c.1521_1523delCTT), 621+1G>T (c.489+1G>T), and p.Ala455Glu (p.A455E; c.1364C>A).3,4 Molecular CFTR testing is usually performed to confirm a clinical diagnosis of CF, to determine carrier status in individuals at risk, or to corroborate results of newborn screening. Login to comment
62 None of the CF probands of our cohort identified as originating from the SLSJ region were found to be carriers of the p.Ser489X variant, whereas Madore et al.4 had reported this variant in one of their SLSJ CF patients, with an estimated allele frequency of 0.59% for this population.The allele frequencies of two of the three most common SLSJ CFTR mutations, namely p.Phe508del and p.Ala455Glu, are similar in our cohort to those reported by Madore et al.4 for this population. Login to comment
55 Frequencies of CFTR disease-causing alleles in the French-Canadian cystic fibrosis patient population CFTR variant All variants p.Phe508del 621+1G>T 711+1G>T p.Ala455Glu p.Ser489X p.Arg334Trp 3199del6 p.Gly542X p.Gly85Glu p.Ile507del FC SLSJ FC SLSJ FC SLSJ FC SLSJ FC SLSJ FC SLSJ FC SLSJ FC SLSJ FC SLSJ FC SLSJ FC SLSJ Number of CF chromosomes 1712 172 1321 116 143 29 61 1 51 13 12 0 9 0 8 2 6 1 5 1 4 1 % Of total CF chromosomes 100.00 100.00 77.16 67.44 8.35 16.86 3.56 0.58 2.98 7.56 0.70 0.00 0.53 0.00 0.47 1.16 0.35 0.58 0.29 0.58 0.23 0.58 CF, cystic fibrosis; FC, French-Canadian; SLSJ, Saguenay-Lac-St-Jean. Login to comment
61 None of the CF probands of our cohort identified as originating from the SLSJ region were found to be carriers of the p.Ser489X variant, whereas Madore et al.4 had reported this variant in one of their SLSJ CF patients, with an estimated allele frequency of 0.59% for this population.The allele frequencies of two of the three most common SLSJ CFTR mutations, namely p.Phe508del and p.Ala455Glu, are similar in our cohort to those reported by Madore et al.4 for this population. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... J Cyst Fibros. 2012 Sep;11(5):355-62. doi: 10.1016/j.jcf.2012.05.001. Epub 2012 Jun 2. Ooi CY, Durie PR
Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in pancreatitis.
J Cyst Fibros. 2012 Sep;11(5):355-62. doi: 10.1016/j.jcf.2012.05.001. Epub 2012 Jun 2., [PMID:22658665]

Abstract [show]
BACKGROUND: The pancreas is one of the primary organs affected by dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. While exocrine pancreatic insufficiency is a well-recognized complication of cystic fibrosis (CF), symptomatic pancreatitis is often under-recognized. RESULTS: The aim of this review is to provide a general overview of CFTR mutation-associated pancreatitis, which affects patients with pancreatic sufficient CF, CFTR-related pancreatitis, and idiopathic pancreatitis. The current hypothesis regarding the role of CFTR dysfunction in the pathogenesis of pancreatitis, and concepts on genotype-phenotype correlations between CFTR and symptomatic pancreatitis will be reviewed. Symptomatic pancreatitis occurs in 20% of pancreatic sufficient CF patients. In order to evaluate genotype-phenotype correlations, the Pancreatic Insufficiency Prevalence (PIP) score was developed and validated to determine severity in a large number of CFTR mutations. Specific CFTR genotypes are significantly associated with pancreatitis. Patients who carry genotypes with mild phenotypic effects have a greater risk of developing pancreatitis than patients carrying genotypes with moderate-severe phenotypic consequences at any given time. CONCLUSIONS: The genotype-phenotype correlation in pancreatitis is unique compared to other organ manifestations but still consistent with the complex monogenic nature of CF. Paradoxically, genotypes associated with otherwise mild phenotypic effects have a greater risk for causing pancreatitis; compared with genotypes associated with moderate to severe disease phenotypes. Greater understanding into the underlying mechanisms of disease is much needed. The emergence of CFTR-assist therapies may potentially play a future role in the treatment of CFTR-mutation associated pancreatitis.

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847 Total PI Total PI+PS PIP score 621+1G>T 96 96 1.00 Classes I - III 711+1G>T 36 36 1.00 Classes I - III R553X 24 24 1.00 Classes I - III I507del 34 34 1.00 Classes I - III G542X 74 75 0.99 Classes I - III F508del 1276 1324 0.96 Classes I - III 1717-1G>A 20 21 0.95 Classes I - III W1282X 19 20 0.95 Classes I - III N1303K 45 48 0.94 Classes I - III R1162X 12 13 0.92 Classes I - III G551D 59 67 0.88 Classes I - III G85E 16 22 0.73 Classes I - III A455E 18 37 0.49 Classes IV - V 2789+5G>A 6 16 0.38 Classes IV - V R334W 1 10 0.10 Classes IV - V 3849+10kbC>T 2 22 0.09 Classes IV - V R117H 1 25 0.04 Classes IV - V Mutation Canadian Consortium for CF Genetic Studies Mutation class The PIP score for a specific mutation is the ratio between the pancreatic insufficient patients carrying the mutation (Total PI) and all pancreatic insufficient and sufficient patients (Total PI+PS) carrying the same mutation in a homozygous state or heterozygous in a combination with a severe mutation such as F508del, G551D or a Class I mutation. Login to comment
855 CFTR mutation Total PI Total PI + PS PIP score CFTR mutation Total PI Total PI + PS PIP score 621+1G>T 96 96 1.00 G542X 74 75 0.99 711+1G>T 36 36 1.00 F508del 1276 1324 0.96 I507del 34 34 1.00 1717-1G>A 20 21 0.95 R553X 24 24 1.00 W1282X 19 20 0.95 Q493X 11 11 1.00 N1303K 45 48 0.94 S489X 11 11 1.00 R1162X 12 13 0.92 1154insTC 10 10 1.00 Y1092X 12 13 0.92 3659delC 9 9 1.00 I148T 10 11 0.91 CFTRdele2 7 7 1.00 V520F 9 10 0.90 4016insT 7 7 1.00 G551D 59 67 0.88 E60X 7 7 1.00 L1077P 5 6 0.83 R560T 7 7 1.00 R1066C 5 6 0.83 R1158X 7 7 1.00 2184insA 9 12 0.75 3905insT 6 6 1.00 2143delT 3 4 0.75 I148T;3199del6 5 5 1.00 1161delC 3 4 0.75 2183AA>G 5 5 1.00 3120+1G>A 3 4 0.75 1898+1G>A 5 5 1.00 S549N 3 4 0.75 2347delG 4 4 1.00 G85E 16 22 0.73 Q1313X 3 3 1.00 R117C 2 3 0.67 Q220X 3 3 1.00 M1101K 19 30 0.63 2184delA 3 3 1.00 P574H 3 5 0.60 1078delT 3 3 1.00 474del13BP 1 2 0.50 L1254X 3 3 1.00 R352Q 1 2 0.50 E585X 3 3 1.00 Q1291H 1 2 0.50 3876delA 2 2 1.00 A455E 18 37 0.49 S4X 2 2 1.00 R347P 6 15 0.40 R1070Q 2 2 1.00 2789+5G>A 6 16 0.38 F508C 2 2 1.00 L206W 6 18 0.33 DELI507 2 2 1.00 IVS8-5T 4 16 0.25 Q1411X 2 2 1.00 3272-26A>G 1 4 0.25 365-366insT 2 2 1.00 R334W 1 10 0.10 R709X 2 2 1.00 3849+10kbC>T 2 22 0.09 1138insG 2 2 1.00 P67L 1 14 0.07 CFTRdele2-4 2 2 1.00 R117H 1 25 0.04 3007delG 2 2 1.00 R347H 0 5 0.00 Q814X 2 2 1.00 G178R 0 3 0.00 394delTT 2 2 1.00 E116K 0 2 0.00 406-1G>A 2 2 1.00 875+1G>C 0 2 0.00 R75X 2 2 1.00 V232D 0 2 0.00 CFTRdel2-3 2 2 1.00 D579G 0 2 0.00 E193X 2 2 1.00 L1335P 0 2 0.00 185+1G>T 2 2 1.00 Mild mutations (based on PIP scores) are shaded in gray. Login to comment

[hide] Newborn screening for cystic fibrosis: Polish 4 ye... Eur J Hum Genet. 2012 Aug 15. doi: 10.1038/ejhg.2012.180. Sobczynska-Tomaszewska A, Oltarzewski M, Czerska K, Wertheim-Tysarowska K, Sands D, Walkowiak J, Bal J, Mazurczak T
Newborn screening for cystic fibrosis: Polish 4 years' experience with CFTR sequencing strategy.
Eur J Hum Genet. 2012 Aug 15. doi: 10.1038/ejhg.2012.180., [PMID:22892530]

Abstract [show]
Newborn screening for cystic fibrosis (NBS CF) in Poland was started in September 2006. Summary from 4 years' experience is presented in this study. The immunoreactive trypsin/DNA sequencing strategy was implemented. The group of 1 212 487 newborns were screened for cystic fibrosis during the programme. We identified a total of 221 CF cases during this period, including, 4 CF cases were reported to be omitted by NBS CF. Disease incidence in Poland based on the programme results was estimated as 1/4394 and carrier frequency as 1/33. The frequency of the F508del was similar (62%) to population data previously reported. This strategy allowed us to identify 29 affected infants with rare genotypes. The frequency of some mutations (eg, 2184insA, K710X) was assessed in Poland for the first time. Thus, sequencing assay seems to be accurate method for screening programme using blood spots in the Polish population.European Journal of Human Genetics advance online publication, 15 August 2012; doi:10.1038/ejhg.2012.180.

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57 Mutations D537N and P731L have not been Period of NBS CF Method The most frequent mutations in Polish population under analysis September 2006 - December 2007 Estonia Asper Biotech assay E60X, G85E, 394delTT, R117H, R117P, R117L, I148T, 621G>A, 711+1G>T, 711+5G>A, 1078delT, R334W, R347H, R347P, R347L, IVS8-T, A455E, I507del, F508del, 1717-1G>A, G542X, p.G551D, Q552X, R553X, R553G, R560T, R560K, 1898+1G>A, 1898+1G>T, 1898+1G>C, 2143delT, 2184delA, 2183AA>G, 2789+5G>A, 3120+1G>A, 3199del6, 3272-26A>G, R1162X, 3659delC, 3849+10kbC>T, 3905insT, S1235R, S1251N, W1282X, W1282C, N1303K, CFTRdele2,3 January 2007 - June 2009 Sanger sequencing of exons: 4, 7, 10, 11, 13, 21, fragment of intron 19 F508del, CFTRdele2,3, 3849+10kbC>T, R117H+IVS8-T*, R334W, R347P, 1717-1G>A, G542X, R553X, K710X, 2184insA, 2143delT, 2183AA>G, N1303K July 2009 - currently Sanger sequencing of exons: 7, 10, 11, 13, 17b, 20, 21, fragment of intron 19 F508del, CFTRdele2,3, 3849+10kbC>T, R334W, R347P, 1717-1G>A, G542X, R553X, K710X, 2184insA, 2143delT, 2183AA>G, N1303K, 3272-26A>G**, W1282X** * removed from DNA analysis since July 2009 , **added into DNA analysis since July 2009 Figure 1 NBS CF in Poland. Login to comment

[hide] Prospective and parallel assessments of cystic fib... Eur J Pediatr. 2012 Aug;171(8):1223-9. Epub 2012 May 12. Krulisova V, Balascakova M, Skalicka V, Piskackova T, Holubova A, Paderova J, Krenkova P, Dvorakova L, Zemkova D, Kracmar P, Chovancova B, Vavrova V, Stambergova A, Votava F, Macek M Jr
Prospective and parallel assessments of cystic fibrosis newborn screening protocols in the Czech Republic: IRT/DNA/IRT versus IRT/PAP and IRT/PAP/DNA.
Eur J Pediatr. 2012 Aug;171(8):1223-9. Epub 2012 May 12., [PMID:22581207]

Abstract [show]
Cystic fibrosis (CF) is a life-threatening disease for which early diagnosis following newborn screening (NBS) improves the prognosis. We performed a prospective assessment of the immunoreactive trypsinogen (IRT)/DNA/IRT protocol currently in use nationwide, versus the IRT/pancreatitis-associated protein (PAP) and IRT/PAP/DNA CF NBS protocols. Dried blood spots (DBS) from 106,522 Czech newborns were examined for IRT concentrations. In the IRT/DNA/IRT protocol, DNA-testing was performed for IRT >/= 65 ng/mL. Newborns with IRT >/= 200 ng/mL and no detected cystic fibrosis transmembrane conductance regulator gene (CFTR) mutations were recalled for a repeat IRT. In the same group of newborns, for both parallel protocols, PAP was measured in DBS with IRT >/= 50 ng/mL. In PAP-positive newborns (i.e., >/=1.8 if IRT 50-99.9 or >/=1.0 if IRT >/= 100, all in ng/mL), DNA-testing followed as part of the IRT/PAP/DNA protocol. Newborns with at least one CFTR mutation in the IRT/DNA/IRT and IRT/PAP/DNA protocols; a positive PAP in IRT/PAP; or a high repeat IRT in IRT/DNA/IRT were referred for sweat testing. CONCLUSION: the combined results of the utilized protocols led to the detection of 21 CF patients, 19 of which were identified using the IRT/DNA/IRT protocol, 16 using IRT/PAP, and 15 using IRT/PAP/DNA. Decreased cut-offs for PAP within the IRT/PAP protocol would lead to higher sensitivity but would increase false positives. Within the IRT/PAP/DNA protocol, decreased PAP cut-offs would result in high sensitivity, an acceptable number of false positives, and would reduce the number of DNA analyses. Thus, we concluded that the IRT/PAP/DNA protocol would represent the most suitable protocol in our conditions.

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81 According to the protocol, this result indicated the sequencing of the Table 1 Parallel comparison of CF NBS protocols IRT/DNAa /IRT IRT/PAP IRT/PAP/DNAa Newborns screened (N) 106,522 106,522 106,522 IRT positives (N; %) 1,158 (1.09) 3,155 (2.96) 3,155 (2.96) PAP positives (N; %) - 260 (0.24) 260 (0.24) Median age (range) at the availability of DNA-testinga results (days) 36 (9-222b ) - 36 (9-222b ) 1 and/or 2 CF mutations detected (N; %) 76 (0.07) - 27 (0.03) Recalled newborns for repeated IRT examination (N; %) 47 (0.04) - - Positive CF NBS (N; %) 123 (0.12) 260 (0.24) 27 (0.03) Positive IRT in newborns recalled for repeated examination (N) 1 - - ST indicated (N; %) 77 (0.07) 260 (0.24) 27 (0.03) ST carried out (N; % of indicated ST) 72c (93.51) 204c (78.46) 24c (88.89) CF carriers (N) 55 - 12 Prevalence of CF carriers 1 in 21 - 1 in 22 Diagnosed CF patients (N) 19 16 15 False positives based on performed ST (N; % of all cases screened) 99d (0.09) 188 (0.18) 9 (0.01) Newborns with equivocal diagnosis [F508del/R117H-IVS-8 T(7) and ST<30 mmol/L; N] 2 - 0 False negatives (N) 2 5 6 Total of CF patients detected (N) 21e Median age (range) at diagnosis (days) 36 (9-57)e CF prevalence 1 in 5,072e Sensitivity (TP/TP+FN) 0.9048 0.7619 0.7142 Specificity (TN/TN+FP) 0.9991 0.9982 0.9999 PPV (TP/TP+FP) 0.1610 0.0784 0.625 N number, % of all cases screened, TP true positives, FN false negatives, TN true negatives, FP false positives, PPV positive predictive value, ST sweat test a CF-causing mutations covered by Elucigene assays ("legacy" nomenclature) with the CF-EU1Tm accounting for: p.Arg347Pro (R347P), c.2657+ 5G>A (2789+5G>A), c.2988+1G>A (3120+1G>A), c.579+1G>T (711+1G>T), p.Arg334Trp (R334W), p.Ile507del (I507del), p.Phe508del (F508del), c.3718-2477C>T (3849+10kbC>T), p.Phe316LeufsX12 (1078delT), p.Trp1282X (W1282X), p.Arg560Thr (R560T), p.Arg553X (R553X), p.Gly551Asp (G551D), p.Met1101Lys (M1101K), p.Gly542X (G542X), p.Leu1258PhefsX7 (3905insT), p.Ser1251Asn (S1251N), c.1585-1G>A (1717-1G>A), p.Arg117His (R117H), p.Asn1303Lys (N1303K), p.Gly85Glu (G85E), c.1766+1G>A (1898+1G>A), p.Lys684AsnfsX38 (2184delA), p.Asp1152His (D1152H), c.54-5940_273+10250del (CFTRdele2,3), p.Pro67Leu (P67L), p.Glu60X (E60X), p.Lys1177SerfsX15 (3659delC), c.489+1G>T (621+1G>T), p.Ala455Glu (A455E), p.Arg1162X (R1162X), p.Leu671X (2143delT), c.1210-12T[n] (IVS8-T(n) variant), including additional mutations in the CF-EU2Tm : p.Gln890X (Q890X), p.Tyr515X (1677delTA), p.Val520Phe (V520F), c.3140-26A>G (3272-26A>G), p.Leu88IlefsX22 (394delTT), p.Arg1066Cys (R1066C), p.Ile105SerfsX2 (444delA), p.Tyr1092X (C>A) (Y1092X(C>A)), p.Arg117Cys (R117C), p.Ser549Asn (S549N), p.Ser549ArgT>G (S549R T>G), p.Tyr122X (Y122X), p.Arg1158X (R1158X), p.Leu206Trp (L206W), c.1680-886A>G (1811+1.6kbA>G), p.Arg347His (R347H), p.Val739TyrfsX16 (2347delG) and p.Trp846X (W846X) b failed DNA isolation from DBS, including repetition of DNA-testing c deceased patient or non-compliance with referrals (five CF carriers in IRT/DNA/IRT, 56 newborns in IRT/PAP, three CF carriers in IRT/PAP/DNA) d comprising newborns with repeated IRT (47 newborns) e aggregate data from all protocols entire CFTR coding region in both newborns, and led to the identification of p.Ile336Lys (I336K) and p.Glu1104Lys (E1104K) mutations. Login to comment

[hide] Improving test properties for neonatal cystic fibr... J Inherit Metab Dis. 2012 Jul;35(4):635-40. Cornel MC, Gille JJ, Loeber JG, Vernooij-van Langen AM, Dankert-Roelse J, Bolhuis PA
Improving test properties for neonatal cystic fibrosis screening in the Netherlands before the nationwide start by May 1st 2011.
J Inherit Metab Dis. 2012 Jul;35(4):635-40., [PMID:22302635]

Abstract [show]
When new technical possibilities arise in health care, often attunement is needed between different actors from the perspectives of research, health care providers, patients, ethics and policy. For cystic fibrosis (CF) such a process of attunement in the Netherlands started in a committee of the Health Council on neonatal screening in 2005. In the balancing of pros and cons according to Wilson and Jungner criteria, the advantages for the CF patient were considered clear, even though CF remains a severe health problem with treatment. Nevertheless, screening was not started then, mainly since the specificity of the tests available at that time was considered too low. Many healthy infants would have been referred for sweat testing and much uncertainty would arise in their parents. Also the limited sensitivity for immigrants and the detection of less severe phenotypes and carriers were considered problematic. The Health Council recommended a pilot screening project which was subsequently performed in some provinces, leading to a 4-step protocol: IRT, PAP, screening for a CFTR mutation panel, and sequencing of the CFTR gene. This would lead to the identification of 23 cases of classical CF, two infants with less severe forms and 12 carriers per year in the Netherlands. Thus many CF patients can be diagnosed early, while limiting the number of referrals, the number of infants with less severe forms diagnosed and the number of carriers identified. Technical solutions were found to limit the ethical problems. A nationwide program using this four step protocol started by 1 May 2011.

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69 This protocol was expected to identify 25 CF patients on an annual basis, additional to four infants already diagnosed because of meconium ileus (Health Council of 1 Using the LiPA test (INNO-LiPA CFTR 19 en INNO-LiPA CFTR 17+Tn; Innogenetics, Gent, Belgium) the following CFTR mutations can be detected: exon 2-3del (21 kb), 394delTT, E60X, G85E, R117H, 621+1G>T, 711+1G>T, 711+5G>A, 1078delT, R334W, R347P, A455E, I507del, F508del, 1717-1G>A, G542X, G551D, Q552X, R553X, R560T, 1898+1G>A, 2143delT, 2183AA>G, 2184delA, 2789+5G>A, 3120+1G>A, 3199del6, 3272-26A>G, 3659delC, R1162X, 3849+10kbC>T, 3905insT, S1251N, W1282X en N1303K. Login to comment
70 This test also identifies the CFTR polymorphism Tn in intron 8 which is important in cases where the mutation R117H is detected. Login to comment

[hide] Link between CFTR mutations and ABPA: a systematic... Mycoses. 2012 Jul;55(4):357-65. doi: 10.1111/j.1439-0507.2011.02130.x. Epub 2011 Oct 17. Agarwal R, Khan A, Aggarwal AN, Gupta D
Link between CFTR mutations and ABPA: a systematic review and meta-analysis.
Mycoses. 2012 Jul;55(4):357-65. doi: 10.1111/j.1439-0507.2011.02130.x. Epub 2011 Oct 17., [PMID:21999194]

Abstract [show]
Summary There is a biological plausibility on the link between cystic fibrosis transmembrane conductance regulator (CFTR) mutations and allergic bronchopulmonary aspergillosis (ABPA). The aim of the systematic review was to investigate this link by determining the frequency of CFTR mutations in ABPA. We searched the PubMed and EmBase databases for studies reporting CFTR mutations in ABPA. We pooled the odds ratio (OR) and 95% confidence intervals (CI) from individual studies using both fixed and random effects model. Statistical heterogeneity was evaluated using the I(2) test and the Cochran-Q statistic. Publication bias was assessed using both graphical and statistical methods. Our search yielded four studies (79 ABPA, 268 controls). The odds of encountering CFTR mutation was higher in ABPA compared with the control group (OR 10.39; 95% CI, 4.35-24.79) or the asthma population (OR 5.53; 95% CI 1.62-18.82). There was no evidence of statistical heterogeneity or publication bias. There is a possible pathogenetic link between CFTR mutations and ABPA. However, because of the small numbers of patients, further studies are required to confirm this finding. Future studies should adopt a uniform methodology and should screen for the entire genetic sequence of the CFTR gene.

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56 (1996)[30] 11ABPA53chronic bronchitis Asthma,pulmonaryinfiltrates,CB, immediateAfskintestpositivity,totalIgE >1000ngml)1 ,positiveAfprecipitins, elevatedAfIgG/IgE,bloodeosinophilia, sweatchloride<40mmoll)1 /(United States) BothgroupssixmutationsF508del, G542X,GS51D,R553X,W1282X andN1303K;ninemoremutations inABPA:R117H,R347P,R347H, R334W,A455E,G551S, 2789+5G>A,D1152H,and 3849+10kbC>T ReverseASOanalysis andDGGEwithDNA sequencing 1patientcarried2CF (F508del;R347H)and5 carried1CF(4F508del; 1R117H).Mutationsseenin 6/11ABPAvs.1/53 controls Aronetal. Login to comment
59 (2002)[33] 31ABPAHealthycontrols (n=34) Asthma(n=51) Asthma,positiveSPTtoAf,totalIgE >1000ngml)1 ,elevatedAf-IgE,positive precipitinstoAf,bloodeosinophilia >350ll)1 ,pulmonaryinfiltratesonCXR orCBonCT/(NewZealand) 16CFmutations-F508del,I507del, R117H,W1282X,621+1G>T, R334W,R347P,A455E, 1717-1G>A,G542X,5549N, G551D,R553X,R560T,N1303Kand 3849+10kbC>T ASOhybridisationand DGGEwithDNA sequencing 4/31(F508del[n=3], R117H[n=1])vs.2/51 asthma(F508del[n=1], R117H[n=1])vs.1/34 healthycontrols ABPA,allergicbronchopulmonaryaspergillosis;ARMS,amplificationrefractorymutationsystem;ASO,allele-specificoligonucleotide;CB,centralbronchiectasis;CFTR,cysticfibrosis transmembraneconductanceregulator;DGGE,denaturinggradientgelelectrophoresis;OR,oddsratio CFTRmutationclass(classI--1717-1G>A,R1162X,G542X;classII--F508del,N1303K;classIV--R347H,R117H). Login to comment

[hide] Rapid detection of the ACMG/ACOG-recommended 23 CF... J Biomol Tech. 2012 Apr;23(1):24-30. Elliott AM, Radecki J, Moghis B, Li X, Kammesheidt A
Rapid detection of the ACMG/ACOG-recommended 23 CFTR disease-causing mutations using ion torrent semiconductor sequencing.
J Biomol Tech. 2012 Apr;23(1):24-30., [PMID:22468138]

Abstract [show]
Cystic fibrosis (CF) is one of the most frequently diagnosed autosomal-recessive diseases in the Caucasian population. For general-population CF carrier screening, the American College of Medical Genetics (ACMG)/American College of Obstetricians and Gynecologists (ACOG) have recommended a core panel of 23 mutations that will identify 49-98% of carriers, depending on ethnic background. Using a genotyping technology that can rapidly identify disease-causing mutations is important for high-throughput general-population carrier screening, confirming clinical diagnosis, determining treatment options, and prenatal diagnosis. Here, we describe a proof-of-concept study to determine whether the Ion Torrent Personal Genome Machine (PGM) sequencer platform can reliably identify all ACMG/ACOG 23 CF transmembrane conductance regulator (CFTR) mutations. A WT CF specimen along with mutant DNA specimens representing all 23 CFTR mutations were sequenced bidirectionally on the Ion Torrent 314 chip to determine the accuracy of the PGM for CFTR variant detection. We were able to reliably identify all of the targeted mutations except for 2184delA, which lies in a difficult, 7-mer homopolymer tract. Based on our study, we believe PGM sequencing may be a suitable technology for identifying CFTR mutations in the future. However, as a result of the elevated rate of base-calling errors within homopolymer stretches, mutations within such regions currently need to be evaluated carefully using an alternative method.

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26 Amplicons were then pooled together in equimolar concentrations and purified using the T A B L E 1 Data Generation from Three PGM Runs Run Total number of reads Total bases (Mbp) AQ17 total bases (Mbp) AQ17 avg. read length CF WT 101,211 8.5 6.5 68 CF 23 pooled mutants 222,247 18.6 12.52 64 CF mutant 135,000 11.7 8.8 72 T A B L E 2 CFTR Variant Coverage, Mutant Read Percentage, and Base-Call Accuracy from a WT Library Using PGM Sequencing Variant cDNA position Coverage Mutant read % Accuracy/base G85E c.254G Ͼ A 408 0 99.5 R117H c.350G Ͼ A 3627 0 99.9 621 ϩ 1G Ͼ T c.489 ϩ 1G Ͼ T 245 0 99.6 711 ϩ 1G Ͼ T c.579 ϩ 1G Ͼ T 2660 0 99.9 R334W c.1000C Ͼ T 5419 0 99.7 R347P c.1040G Ͼ C 3562 0 99.4 A455E c.1364C Ͼ A 10,340 0 99.9 ⌬I507 c.1519_1521delATC 6507 0 98.6 ⌬F508 c.1521_1523delCTT 6507 0 99.4 1717-1G Ͼ A c.1585-1G Ͼ A 2086 0 99.2 G542X c.1624G Ͼ T 854 0 97.8 G551D c.1652G Ͼ A 3901 0 99 R553X c.1657C Ͼ T 3915 0 99.9 R560T c.1679G Ͼ C 3924 0 99.6 1898 ϩ 1G Ͼ A c.1766 ϩ 1G Ͼ A 1793 0 97.6 2184delAa c.2052delA 2001 35% 63.6 2789 ϩ 5G Ͼ A c.2657 ϩ 5G Ͼ A 293 0 100 3120 ϩ 1G Ͼ A c.2988 ϩ 1G Ͼ A 2408 0 100 R1162X c.3484C Ͼ T 9610 0 98.1 3659delC c.3528delC 9271 0 100 3849 ϩ 10kbC Ͼ T c.3717 ϩ 12191C Ͼ T 10,157 0 99.9 W1282X c.3846G Ͼ A 4789 0 95.6 N1303K c.3909C Ͼ G 3236 0 99.5 a The 2184delA variant lies in a homopolymer stretch of seven adenines and is not detected accurately as a result of homopolymer-length sequencing errors. Login to comment
67 For this data set, the PGM 314 chip output was 18.6 Mbp, with ϳ67% aligning to the CFTR T A B L E 3 PGM CFTR Variant Coverage and Mutant Read Percentage from a Pooled Mutant Library Representing All 23 ACMG/ACOG Mutations Variant cDNA position Coverage Mutant read % Predicted read % Genotype G85E c.254G Ͼ A 93 33 50 Het R117H c.350G Ͼ A 6228 39 50 Het 621 ϩ 1G Ͼ T c.489 ϩ 1G Ͼ T 1243 46 50 Het 711 ϩ 1G Ͼ T c.579 ϩ 1G Ͼ T 1352 29 50 Het R334W c.1000C Ͼ T 13,284 8 25 Het R347P c.1040G Ͼ C 9454 27 25 Het A455E c.1364C Ͼ A 19,527 43 50 Het ⌬I507 c.1519_1521delATC 15,587 14 25 Het ⌬F508 c.1521_1523delCTT 15,587 68 50 Homo 1717-1G Ͼ A c.1585-1G Ͼ A 3584 36 50 Het G542X c.1624G Ͼ T 610 41 50 Het G551D c.1652G Ͼ A 6714 16 17 Het R553X c.1657C Ͼ T 6670 15 17 Het R560T c.1679G Ͼ C 6395 22 17 Het 1898 ϩ 1G Ͼ A c.1766 ϩ 1G Ͼ A 3293 49 50 Het 2184delAa c.2052delA 2256 63 50 Het 2789 ϩ 5G Ͼ A c.2657 ϩ 5G Ͼ A 1765 54 50 Het 3120 ϩ 1G Ͼ A c.2988 ϩ 1G Ͼ A 7447 40 50 Het R1162X c.3484C Ͼ T 19,060 54 50 Het 3659delC c.3528delC 28,321 30 50 Het 3849 ϩ 10kbC Ͼ T c.3717 ϩ 12191C Ͼ T 27,102 46 50 Het W1282X c.3846G Ͼ A 9219 48 50 Het N1303K c.3909C Ͼ G 4842 49 50 Het a The 2184delA variant lies in a homopolymer stretch of seven adenines and is not accurately detected as a result of homopolymer-length sequencing errors. Login to comment
86 Using samples characterized previously, we analyzed the PGM`s data out- T A B L E 4 PGM CFTR Variant Coverage and Mutant Read Percentage from an Individual Harboring Two Disease-Causing CFTR Mutations Variant cDNA position Coverage Mutant read % G85E c.254G Ͼ A 237 0 R117H c.350G Ͼ A 3774 0 621 ϩ 1G Ͼ T c.489 ϩ 1G Ͼ T 936 0 711 ϩ 1G Ͼ T c.579 ϩ 1G Ͼ T 2018 0 R334W c.1000C Ͼ T 10,899 0 R347P c.1040G Ͼ C 7720 0 A455E c.1364C Ͼ A 14,525 0 ⌬I507 c.1519_1521delATC 8855 0 ⌬F508 c.1521_1523delCTT 8855 47 1717-1G Ͼ A c.1585-1G Ͼ A 2216 0 G542X c.1624G Ͼ T 2035 41 G551D c.1652G Ͼ A 4581 0 R553X c.1657C Ͼ T 4545 0 R560T c.1679G Ͼ C 4774 0 1898 ϩ 1G Ͼ A c.1766 ϩ 1G Ͼ A 2702 0 2184delAa c.2052delA 2837 18.5 2789 ϩ 5G Ͼ A c.2657 ϩ 5G Ͼ A 860 0 3120 ϩ 1G Ͼ A c.2988 ϩ 1G Ͼ A 4347 0 R1162X c.3484C Ͼ T 12,039 0 3659delC c.3528delC 7169 0 3849 ϩ 10kbC Ͼ T c.3717 ϩ 12191C Ͼ T 11,588 0 W1282X c.3846G Ͼ A 6187 0 N1303K c.3909C Ͼ G 4479 0 a The 2184delA variant lies in a homopolymer stretch of seven adenines and is not accurately detected as a result of homopolymer-length sequencing errors. Login to comment
66 For this data set, the PGM 314 chip output was 18.6 Mbp, with b03;67% aligning to the CFTR T A B L E 3 PGM CFTR Variant Coverage and Mutant Read Percentage from a Pooled Mutant Library Representing All 23 ACMG/ACOG Mutations Variant cDNA position Coverage Mutant read % Predicted read % Genotype G85E c.254G b0e; A 93 33 50 Het R117H c.350G b0e; A 6228 39 50 Het 621 af9; 1G b0e; T c.489 af9; 1G b0e; T 1243 46 50 Het 711 af9; 1G b0e; T c.579 af9; 1G b0e; T 1352 29 50 Het R334W c.1000C b0e; T 13,284 8 25 Het R347P c.1040G b0e; C 9454 27 25 Het A455E c.1364C b0e; A 19,527 43 50 Het èc;I507 c.1519_1521delATC 15,587 14 25 Het èc;F508 c.1521_1523delCTT 15,587 68 50 Homo 1717-1G b0e; A c.1585-1G b0e; A 3584 36 50 Het G542X c.1624G b0e; T 610 41 50 Het G551D c.1652G b0e; A 6714 16 17 Het R553X c.1657C b0e; T 6670 15 17 Het R560T c.1679G b0e; C 6395 22 17 Het 1898 af9; 1G b0e; A c.1766 af9; 1G b0e; A 3293 49 50 Het 2184delAa c.2052delA 2256 63 50 Het 2789 af9; 5G b0e; A c.2657 af9; 5G b0e; A 1765 54 50 Het 3120 af9; 1G b0e; A c.2988 af9; 1G b0e; A 7447 40 50 Het R1162X c.3484C b0e; T 19,060 54 50 Het 3659delC c.3528delC 28,321 30 50 Het 3849 af9; 10kbC b0e; T c.3717 af9; 12191C b0e; T 27,102 46 50 Het W1282X c.3846G b0e; A 9219 48 50 Het N1303K c.3909C b0e; G 4842 49 50 Het a The 2184delA variant lies in a homopolymer stretch of seven adenines and is not accurately detected as a result of homopolymer-length sequencing errors. Login to comment
85 Using samples characterized previously, we analyzed the PGM`s data out- T A B L E 4 PGM CFTR Variant Coverage and Mutant Read Percentage from an Individual Harboring Two Disease-Causing CFTR Mutations Variant cDNA position Coverage Mutant read % G85E c.254G b0e; A 237 0 R117H c.350G b0e; A 3774 0 621 af9; 1G b0e; T c.489 af9; 1G b0e; T 936 0 711 af9; 1G b0e; T c.579 af9; 1G b0e; T 2018 0 R334W c.1000C b0e; T 10,899 0 R347P c.1040G b0e; C 7720 0 A455E c.1364C b0e; A 14,525 0 èc;I507 c.1519_1521delATC 8855 0 èc;F508 c.1521_1523delCTT 8855 47 1717-1G b0e; A c.1585-1G b0e; A 2216 0 G542X c.1624G b0e; T 2035 41 G551D c.1652G b0e; A 4581 0 R553X c.1657C b0e; T 4545 0 R560T c.1679G b0e; C 4774 0 1898 af9; 1G b0e; A c.1766 af9; 1G b0e; A 2702 0 2184delAa c.2052delA 2837 18.5 2789 af9; 5G b0e; A c.2657 af9; 5G b0e; A 860 0 3120 af9; 1G b0e; A c.2988 af9; 1G b0e; A 4347 0 R1162X c.3484C b0e; T 12,039 0 3659delC c.3528delC 7169 0 3849 af9; 10kbC b0e; T c.3717 af9; 12191C b0e; T 11,588 0 W1282X c.3846G b0e; A 6187 0 N1303K c.3909C b0e; G 4479 0 a The 2184delA variant lies in a homopolymer stretch of seven adenines and is not accurately detected as a result of homopolymer-length sequencing errors. Login to comment

[hide] Novel strategies in newborn screening for cystic f... Thorax. 2012 Apr;67(4):289-95. Epub 2012 Jan 23. Vernooij-van Langen AM, Loeber JG, Elvers B, Triepels RH, Gille JJ, Van der Ploeg CP, Reijntjens S, Dompeling E, Dankert-Roelse JE
Novel strategies in newborn screening for cystic fibrosis: a prospective controlled study.
Thorax. 2012 Apr;67(4):289-95. Epub 2012 Jan 23., [PMID:22271776]

Abstract [show]
CONTEXT: Newborn screening for cystic fibrosis (CF) is included in many routine programmes but current strategies have considerable drawbacks, such as false-positive tests, equivocal diagnosis and detection of carriers. OBJECTIVE: To assess the test performance of two newborn screening strategies for CF. DESIGN, SETTING AND PARTICIPANTS: In 2008 and 2009, CF screening was added to the routine screening programme as a prospective study in part of The Netherlands. INTERVENTIONS: Two strategies were performed in all newborns. In the first strategy, concentrations of immunoreactive trypsinogen (IRT) and pancreatitis-associated protein (PAP) were measured. In the second method, samples with IRT >/=60 mug/litre were analysed for 36 CFTR mutations, followed by sequencing when a single mutation was detected. Tests were positive only with two identified CFTR mutations. MAIN OUTCOME: Sensitivity, specificity and positive predictive value (PPV) of both screening strategies. RESULTS: 145,499 infants were screened. The IRT/PAP approach showed a sensitivity of 95.0%, a specificity of 99.897% and a PPV of 12.3%. Test properties for the IRT/DNA/sequencing strategy were respectively 100%, 100% and 64.9%. Combining both strategies (IRT/PAP/DNA/sequencing) led to a sensitivity of 95.0%, a specificity of 100% and a PPV of 87.5%. CONCLUSION: In conclusion, all strategies performed well. Although there was no statistically significant difference in test performance, the IRT/DNA/sequencing strategy detected one infant that was missed by IRT/PAP (/DNA/sequencing). IRT/PAP may be the optimal choice if the use of DNA technology must be avoided. If identification of carriers and equivocal diagnosis is considered an important disadvantage, IRT/PAP/DNA/sequencing may be the best choice.

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80 One infant was missed because of a low PAP concentration (0.8 mg/litre); this infant had two mutations (F508del and A455E) and a positive sweat test (chloride 65 mmol/litre). Login to comment
110 Table 2 Immunoreactive trypsinogen and pancreatitis-associated protein concentrations, CFTR gene mutation analysis and sweat tests in infants with cystic fibrosis detected by newborn screening IRT (mg/litre) PAP (mg/litre) Mutation 1 Mutation 2 Sweat test chloride (mmol/litre) 1 438 5.3 F508del F508del 74 2 284 1.8 F508del F508del 88 3 266 9.8 F508del F508del 97 4 237 1.8 F508del F508del 11 and 74 5 197 4.3 F508del F508del 69 6* 191 12.6 F508del C.3889dupT 94 7 164 14.4 F508del G542X 102 8 129 4.3 F508del F508del Failed 9 110 2.2 F508del F508del 94 10 109 2.0 F508del F508del 51 11 105 4.4 F508del F508del 149 12 155 2.6 F508del F508del 111 13 191 12.6 F508del F508del 4 14 116 15.8 F508del F508del Failed 3 times 15 293 5.7 F508del 2184A 120 16* 228 15.8 F508del 1294_1300del 99 17 218 4.5 F508del G85E 99 18 153 4.0 F508del S1251N 77 19* 141 15.8 F508del E730X 82 20z 78 0.8 F508del A455E 65 21y 114 11.2 F508del F508del Failed 22y 109 0.8 F508del F508del 78 23y 93 1.3 F508del F508del e 24y 75 6.7 F508del F508del 78 *Second mutation detected by sequencing. Login to comment
79 One infant was missed because of a low PAP concentration (0.8 mg/litre); this infant had two mutations (F508del and A455E) and a positive sweat test (chloride 65 mmol/litre). Login to comment
109 Table 2 Immunoreactive trypsinogen and pancreatitis-associated protein concentrations, CFTR gene mutation analysis and sweat tests in infants with cystic fibrosis detected by newborn screening IRT (mg/litre) PAP (mg/litre) Mutation 1 Mutation 2 Sweat test chloride (mmol/litre) 1 438 5.3 F508del F508del 74 2 284 1.8 F508del F508del 88 3 266 9.8 F508del F508del 97 4 237 1.8 F508del F508del 11 and 74 5 197 4.3 F508del F508del 69 6* 191 12.6 F508del C.3889dupT 94 7 164 14.4 F508del G542X 102 8 129 4.3 F508del F508del Failed 9 110 2.2 F508del F508del 94 10 109 2.0 F508del F508del 51 11 105 4.4 F508del F508del 149 12 155 2.6 F508del F508del 111 13 191 12.6 F508del F508del 4 14 116 15.8 F508del F508del Failed 3 times 15 293 5.7 F508del 2184A 120 16* 228 15.8 F508del 1294_1300del 99 17 218 4.5 F508del G85E 99 18 153 4.0 F508del S1251N 77 19* 141 15.8 F508del E730X 82 20z 78 0.8 F508del A455E 65 21y 114 11.2 F508del F508del Failed 22y 109 0.8 F508del F508del 78 23y 93 1.3 F508del F508del e 24y 75 6.7 F508del F508del 78 *Second mutation detected by sequencing. Login to comment

[hide] CFTR, SPINK1, CTRC and PRSS1 variants in chronic p... Gut. 2012 Mar 17. Rosendahl J, Landt O, Bernadova J, Kovacs P, Teich N, Bodeker H, Keim V, Ruffert C, Mossner J, Kage A, Stumvoll M, Groneberg D, Kruger R, Luck W, Treiber M, Becker M, Witt H
CFTR, SPINK1, CTRC and PRSS1 variants in chronic pancreatitis: is the role of mutated CFTR overestimated?
Gut. 2012 Mar 17., [PMID:22427236]

Abstract [show]
OBJECTIVE: In chronic pancreatitis (CP), alterations in several genes have so far been described, but only small cohorts have been extensively investigated for all predisposing genes. DESIGN: 660 patients with idiopathic or hereditary CP and up to 1758 controls were enrolled. PRSS1, SPINK1 and CTRC were analysed by DNA sequencing, and cystic fibrosis transmembrane conductance regulator (CFTR) by melting curve analysis. RESULTS: Frequencies of CFTR variants p.R75Q, p.I148T, 5T-allele and p.E528E were comparable in patients and controls. We identified 103 CFTR variants, which represents a 2.7-fold risk increase (p<0.0001). Severe cystic fibrosis (CF)-causing variants increased the risk of developing CP 2.9-fold, and mild CF-causing variants 4.5-fold (p<0.0001 for both). Combined CF-causing variants increased CP risk 3.4-fold (p<0.0001), while non-CF-causing variants displayed a 1.5-fold over-representation in patients (p=0.14). CFTR compound heterozygous status with variant classes CF-causing severe and mild represented an OR of 16.1 (p<0.0001). Notably, only 9/660 (1.4%) patients were compound heterozygotes in this category. Trans-heterozygosity increased CP risk, with an OR of 38.7, with 43/660 (6.5%) patients and 3/1667 (0.2%) controls being trans-heterozygous (p<0.0001). CONCLUSIONS: Accumulation of CFTR variants in CP is less pronounced than reported previously, with ORs between 2.7 and 4.5. Only CF-causing variants reached statistical significance. Compound and trans-heterozygosity is an overt risk factor for the development of CP, but the number of CFTR compound heterozygotes in particular is rather low. In summary, the study demonstrates the complexity of genetic interactions in CP and a minor influence of CFTR alterations in CP development.

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72 The following CFTR variants were analysed with specific FRET probes: p.E60X, p.R75Q, p.G85E, p.R117H, p.I148T, c.621 +1G>T (IVS4+1G>T), c.711+1G>T (IVS5+1G>T), c.1078delT, p.R334W, p.R347P, 9-13TG, 5-9T, p.A455E, p.M470V, p.F508del, c.1716G>A (p.E528E), c.1717-1G>A (IVS10-1G>A), p.G542X, p.S549N, p.R553X, p.R560T, c.1898+1G>A (IVS12 +1G>A), c.2143delT, c.2183AA>G, c.2562T>G, c.2657+5G>A (IVS14B+5G>A), p.L997F, p.I1005R, p.Y1092X, p.D1152H, p.R1162X, c.3659delC, p.S1235R, p.S1251N, p.W1282X, p.N1303K, and c.4389G>A. Login to comment
140 Variant distribution in patients aged >20 and <20 years In younger patients, overall PRSS1 variants were 2.9-fold more common (>20 years: 9/239, 3.8%; <20 years: 46/421, 10.9%; p¼0.001, OR 3.1, 95% CI 1.5 to 6.5), whereas overall SPINK1 variants were similarly distributed (56/239, 23.4%; 73/421, Table 2 CFTR variants detected by melting curve analysis Gene Variant Patients Controls p Value OR (95% CI) CFTR (CF-causing, severe) p.F508del 44/660 (6.7%) 48/1758 (2.7%) <0.0001 2.5 (1.7 to 3.9) p.R117H (5T/7T) 2/660 (0.3%) 1/1758 (0.06%) NS e p.G542X 1/660 (0.2%) 1/1758 (0.06%) NS e c.1717-1G>A 3/660 (0.5%) 1/1758 (0.06%) NS e p.E585X 0/660 1/1758 (0.06%) NS e c.2183AA>G 0/660 1/1758 (0.06%) NS e p.R1158X 1/660 (0.2%) 0/1758 NS e p.R1162X 1/660 (0.3%) 0/1758 NS e p.N1303K 3/660 (0.5%) 0/1758 NS e Total 55/660 (8.3%) 53/1758 (3%) <0.0001 2.9 (2 to 4.3) CFTR (CF-causing mild) p.R117H (7T/7T) 13/660 (2%) 8/1758 (0.5%) 0.0009 4.4 (1.8 to 10.7) p.R117H (7T/9T) 3/660 (0.5%) 1/1758 (0.06%) NS e p.R347H 1/660 (0.2%) 0/1758 NS e p.R347P 1/660 (0.2%) 0/1758 NS e p.A455E 1/660 (0.2%) 0/1758 NS e c.2657+5G>A 1/660 (0.2%) 0/1758 NS e p.D1152H 3/660 (0.5%) 5/1758 (0.3%) NS e Total 23/660 (3.5%) 14/1758 (0.8%) <0.0001 4.5 (2.3 to 8.8) CFTR (non CF-causing) p.R74Q 2/660 (0.3%) 0/1758 NS e p.R75Q (het)* 29/660 (4.4%) 59/1758 (3.4%) NS e p.R75Q (hom)* 2/660 (0.3%) 1/1758 (0.06%) NS e p.Y84H 0/660 1/1758 (0.06%) NS e p.A120T 0/660 1/1758 (0.06%) NS e p.I148T* 4/660 (0.6%) 11/1758 (0.6%) NS e p.I507V 1/660 (0.2%) 2/1758 (0.1%) NS e p.F508C 1/660 (0.2%) 0/1758 NS e c.1716+12T>C 0/660 1/1758 (0.06%) NS e p.E528E (het)* 36/660 (5.5%) 82/1758 (4.7%) NS e p.E528E (hom)* 0/660 2/1758 (0.1%) NS e c.1898+8C>G 0/660 1/1758 (0.06%) NS e p.H667Y 1/660 (0.2%) 0/1758 NS e p.R668C 5/660 (0.8%) 3/1758 (0.2%) NS e p.G691R 0/660 1/1758 (0.06%) NS e p.L997F 5/660 (0.8%) 6/1758 (0.3%) NS e p.S1235R 10/660 (1.5%) 18/1758 (1.0%) NS e Total (excluded)* 25/660 (3.8%) 45/1758 (2.6%) NS e CFTR (CF-causing) Total (all) 78/660 (11.8%) 67/1758 (3.8%) <0.0001 3.4 (2.4 to 4.8) CFTR (all) Total (excluded)* 103/660 (15.6%) 112/1758 (6.4%) <0.0001 2.7 (2 to 3.6) The table is divided into three parts. Login to comment
69 The following CFTR variants were analysed with specific FRET probes: p.E60X, p.R75Q, p.G85E, p.R117H, p.I148T, c.621 +1G>T (IVS4+1G>T), c.711+1G>T (IVS5+1G>T), c.1078delT, p.R334W, p.R347P, 9-13TG, 5-9T, p.A455E, p.M470V, p.F508del, c.1716G>A (p.E528E), c.1717-1G>A (IVS10-1G>A), p.G542X, p.S549N, p.R553X, p.R560T, c.1898+1G>A (IVS12 +1G>A), c.2143delT, c.2183AA>G, c.2562T>G, c.2657+5G>A (IVS14B+5G>A), p.L997F, p.I1005R, p.Y1092X, p.D1152H, p.R1162X, c.3659delC, p.S1235R, p.S1251N, p.W1282X, p.N1303K, and c.4389G>A. Login to comment
135 Variant distribution in patients aged >20 and <20 years In younger patients, overall PRSS1 variants were 2.9-fold more common (>20 years: 9/239, 3.8%; <20 years: 46/421, 10.9%; p&#bc;0.001, OR 3.1, 95% CI 1.5 to 6.5), whereas overall SPINK1 variants were similarly distributed (56/239, 23.4%; 73/421, Table 2 CFTR variants detected by melting curve analysis Gene Variant Patients Controls p Value OR (95% CI) CFTR (CF-causing, severe) p.F508del 44/660 (6.7%) 48/1758 (2.7%) <0.0001 2.5 (1.7 to 3.9) p.R117H (5T/7T) 2/660 (0.3%) 1/1758 (0.06%) NS e p.G542X 1/660 (0.2%) 1/1758 (0.06%) NS e c.1717-1G>A 3/660 (0.5%) 1/1758 (0.06%) NS e p.E585X 0/660 1/1758 (0.06%) NS e c.2183AA>G 0/660 1/1758 (0.06%) NS e p.R1158X 1/660 (0.2%) 0/1758 NS e p.R1162X 1/660 (0.3%) 0/1758 NS e p.N1303K 3/660 (0.5%) 0/1758 NS e Total 55/660 (8.3%) 53/1758 (3%) <0.0001 2.9 (2 to 4.3) CFTR (CF-causing mild) p.R117H (7T/7T) 13/660 (2%) 8/1758 (0.5%) 0.0009 4.4 (1.8 to 10.7) p.R117H (7T/9T) 3/660 (0.5%) 1/1758 (0.06%) NS e p.R347H 1/660 (0.2%) 0/1758 NS e p.R347P 1/660 (0.2%) 0/1758 NS e p.A455E 1/660 (0.2%) 0/1758 NS e c.2657+5G>A 1/660 (0.2%) 0/1758 NS e p.D1152H 3/660 (0.5%) 5/1758 (0.3%) NS e Total 23/660 (3.5%) 14/1758 (0.8%) <0.0001 4.5 (2.3 to 8.8) CFTR (non CF-causing) p.R74Q 2/660 (0.3%) 0/1758 NS e p.R75Q (het)* 29/660 (4.4%) 59/1758 (3.4%) NS e p.R75Q (hom)* 2/660 (0.3%) 1/1758 (0.06%) NS e p.Y84H 0/660 1/1758 (0.06%) NS e p.A120T 0/660 1/1758 (0.06%) NS e p.I148T* 4/660 (0.6%) 11/1758 (0.6%) NS e p.I507V 1/660 (0.2%) 2/1758 (0.1%) NS e p.F508C 1/660 (0.2%) 0/1758 NS e c.1716+12T>C 0/660 1/1758 (0.06%) NS e p.E528E (het)* 36/660 (5.5%) 82/1758 (4.7%) NS e p.E528E (hom)* 0/660 2/1758 (0.1%) NS e c.1898+8C>G 0/660 1/1758 (0.06%) NS e p.H667Y 1/660 (0.2%) 0/1758 NS e p.R668C 5/660 (0.8%) 3/1758 (0.2%) NS e p.G691R 0/660 1/1758 (0.06%) NS e p.L997F 5/660 (0.8%) 6/1758 (0.3%) NS e p.S1235R 10/660 (1.5%) 18/1758 (1.0%) NS e Total (excluded)* 25/660 (3.8%) 45/1758 (2.6%) NS e CFTR (CF-causing) Total (all) 78/660 (11.8%) 67/1758 (3.8%) <0.0001 3.4 (2.4 to 4.8) CFTR (all) Total (excluded)* 103/660 (15.6%) 112/1758 (6.4%) <0.0001 2.7 (2 to 3.6) The table is divided into three parts. Login to comment

[hide] Role of Cystic Fibrosis Transmembrane Conductance ... Chest. 2012 Mar 15. Gonska T, Choi P, Stephenson A, Ellis L, Martin S, Solomon M, Dupuis A, Dorfman R, Zielenski J, Ooi CY, Weiser W, Durie PR, Tullis E
Role of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) in patients with chronic sinopulmonary disease.
Chest. 2012 Mar 15., [PMID:22423042]

Abstract [show]
ABSTRACT INTRODUCTION:Previous studies report a high frequency of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in patients with idiopathic bronchiectasis. However, most studies have based their findings on pre-selected patient groups or have performed limited testing for CFTR dysfunction. The objective of our study was to evaluate the prevalence of CFTR gene mutations and/or CFTR-related ion channel abnormalities among subjects with idiopathic chronic sinopulmonary disease and the prevalence of CF or a CFTR-related disorder in this population. METHODS:We evaluated 72 prospectively enrolled patients from 1995-2005 at the Hospital for Sick Children and St. Michael's Hospital with idiopathic chronic sinopulmonary disease for evidence of CFTR-mediated abnormalities. We performed CFTR genotyping and assessed CFTR function using sweat testing and nasal potential difference testing. The results were compared with data from healthy controls, CF heterozygotes and CF patients. RESULTS:The CFTR functional tests in idiopathic sinopulmonary patients showed a continuous spectrum, ranging from normal to values typically seen in individuals with CF. Forty eight patients (66%) demonstrated CFTR mutations and/or abnormalities of CFTR function. Twenty two (31%) fulfilled criteria for a CF diagnosis and 26 (36%) for a CFTR-related disorder with a strong female preponderance. Functional tests, more than genotyping, were instrumental in establishing a CF diagnosis. Clinical features failed to distinguish CF subjects from those with CFTR-related or idiopathic disease. CONCLUSION:The high prevalence of CF and CFTR dysfunction among patients with idiopathic chronic sinopulmonary disease underscores the need for extensive diagnostic evaluation for CF.

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66 All P values are two-sided with a Table 2-CFTR Genotypes Identified in Subjects With Idiopathic Sinopulmonary Disease CF Causing/CF Causing CF Causing/CFTR Mutation CFTR Mutation/CFTR Mutation CF Causing/Unknown CFTR Mutation/Unknown F508del/A455E 3x F508del /D1152H 2x D579G/D579G 2x F508del /26x R764X/2 F508del/S1251N R75X/V456A 758delC/2 F508del/L967S 1716G.A/5T 1716G.A/2 F508del/5T R75Q/5T R117H (7T)/23x F508del/3212T.C 5T/23x G542X/D1152H 1717-1G.A/Q1291H Patients are grouped according to the identified CFTR alterations on allele 1/allele 2. Login to comment

[hide] CFTR mutation analysis and haplotype associations ... Mol Genet Metab. 2012 Feb;105(2):249-54. doi: 10.1016/j.ymgme.2011.10.013. Epub 2011 Oct 26. Cordovado SK, Hendrix M, Greene CN, Mochal S, Earley MC, Farrell PM, Kharrazi M, Hannon WH, Mueller PW
CFTR mutation analysis and haplotype associations in CF patients.
Mol Genet Metab. 2012 Feb;105(2):249-54. doi: 10.1016/j.ymgme.2011.10.013. Epub 2011 Oct 26., [PMID:22137130]

Abstract [show]
Most newborn screening (NBS) laboratories use second-tier molecular tests for cystic fibrosis (CF) using dried blood spots (DBS). The Centers for Disease Control and Prevention's NBS Quality Assurance Program offers proficiency testing (PT) in DBS for CF transmembrane conductance regulator (CFTR) gene mutation detection. Extensive molecular characterization on 76 CF patients, family members or screen positive newborns was performed for quality assurance. The coding, regulatory regions and portions of all introns were sequenced and large insertions/deletions were characterized as well as two intronic di-nucleotide microsatellites. For CF patient samples, at least two mutations were identified/verified and four specimens contained three likely CF-associated mutations. Thirty-four sequence variations in 152 chromosomes were identified, five of which were not previously reported. Twenty-seven of these variants were used to predict haplotypes from the major haplotype block defined by HapMap data that spans the promoter through intron 19. Chromosomes containing the F508del (p.Phe508del), G542X (p.Gly542X) and N1303K (p.Asn1303Lys) mutations shared a common haplotype subgroup, consistent with a common ancient European founder. Understanding the haplotype background of CF-associated mutations in the U.S. population provides a framework for future phenotype/genotype studies and will assist in determining a likely cis/trans phase of the mutations without need for parent studies.

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104 Mutation N alleles c.966T>G(5'flanking) c.234T>A(5'flanking)a c.-8G>C(5'UTR) c.-4G>C(Exon1) c.274-179G>A(Intron3) c.743+40A>G(Intron6) c.744-31TTGA(5_7)(Intron6) c.869+11C>T(Intron7) c.869+88T>A(Intron7) c.1209+43T>G(Intron9) IVS8CA(15-23)(Intron9) TG(10-13)_T(5-9)(Intron9) c.1393-61A>G(Intron10) M470V(Exon11) F508del(Exon11) c.1766+152T>A(Intron13) c.1767-231T>C(Intron13) c.1767-136T>C(Intron13) c.1767-132A>G(Intron13) c.2562T>G(Exon15) c.2604A>G(Exon15) c.2619+86_2619+87del(Intron15) c.2619+106T>A(Intron15) c.2909-92G>A(Intron17) IVS17bCA(11-17)(Intron20) c.3368-140A>C(Intron20) c.3469-65C>A(Intron21) F508del 32 TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- GA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- A5- 55- 55- 55- 66- 66- 66- 66- 66- 66- 66- 66- 66- 66- 55- 55- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TC- TT- TT- TT- TC- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TG- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- T17- 10_9- G- F508del- TA- 13C F508del 29 G23- 10_9- G- F508del- TA- 13C F508del 1 G21- 10_9- G- GG- G-F508del- TA- 13C F508del 1 G17- 10_9- G- F508del- A- G- delTA- 17- C- A N1303K 6 G542X 6 3849+10kbC→T 1 del Ex17a, b, Ex18 1 GG- GG- GG- 23- 10_9- GG-F508- T- TA- 13- C A455E 1 G22- 10_9- G- F508- T- TA- 13- C 621+1G→T 5 G21- 10_9- G- GG- GG- F508C- TA- 13- C 711+1G→T 3 3272-26A→G 2 3659delC 2 R347P 2 G16- 11_7- A- A-F508- TA- 13C del Ex 2, 3 2 del Ex 17a,17b 2 Normal 1 R334W 2 G17- 11_7- A- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA-AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- A-AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- AA- F508- TA- 13C 2183AA→G 2 G16- 10_7- F508- TATA- TATA- TATA- TATA- TATA- TATA- 13C del Ex 2 1 G16- 11_7- F508- 14C 1288insTA 1 G16- 12_7- F508- 13C Normal 1 G16- 12_7- F508- 13C R1162X 1 G17- 10_7- F508- 13C del Ex 2,3 1 G16- 11_7- F508- A17- C del Ex 17a,17b 1 GA- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT- TT-16- 11_7- F508- 14- C G85E 1 G16- 11_7- F508- 15C 1898+1G→A 1 G16- 11_7- F508- G13- C no mut detected 1 GT- TT- T16- 10_7- F508- 13C no mut detected 1 G16- 10_7- F508- 17A W1282X 2 G17- 10_7- F508- 17A W1282X 4 GC- CC- C17- 10_7- F508- delTA- 17- A Q39X 1 I507del 1 3849+10kbC→T 1 R560T 2 1717-1G→A 2 G551D 3 G16- 10_7- F508- delTA- 17- A G551D 2 1154insTC 1 G16- 10_7- F508- delTA- 17- 1717- 17A 1717-1G→A 1 2789+5G→A 1 GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- G17- 10_7- F508- AdelTA- A R1066C 1 GG- 17- 10_7- F508- delTA- A R1066H 1 GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- GG- G17- 9_7- F508- delTAC R553X 3 GG- GG- CA- AA- AA- AA- A17- 12_7- F508- delTA- 11- C 3121-1G→A 1 C17- 12_7- F508- delTA- 11- C R334W 1 G17- 12_7- F508- TA- 13- C (TG)13T5b 1 G17- 13_5- F508- delTA- 13- C CC- CC- CC- CC- CC- CC- CC- CC- CC- CC- CC- CC- CC- CC- CC- CC- CC- R117H 1 CA- 6C- TT- 15- 12_5- AG- F508- T- TT- AT- ATA- TG- 13A- C R117H1 1 CA- 6C- TT- 16- 12_5- AG- F508- T- TT- AT- ATA- TG- 13A- C 1717-1G→A 1 R117Hb 1 GA- 6C- TT- 16- 10_7- AA- F508- A- TC- AG- AdelTA- TG- 13A- C 144c a Variation found in a sample where the haplotype could not be predicted. Login to comment

[hide] Lessons learned from 20 years of newborn screening... Med J Aust. 2012 Jan 16;196(1):67-70. Massie RJ, Curnow L, Glazner J, Armstrong DS, Francis I
Lessons learned from 20 years of newborn screening for cystic fibrosis.
Med J Aust. 2012 Jan 16;196(1):67-70., [PMID:22256939]

Abstract [show]
OBJECTIVE: To compare three cystic fibrosis (CF) newborn screening strategies used in Victoria since 1989. DESIGN, SETTING AND PARTICIPANTS: Retrospective review of newborn screening and clinical records for people with CF born in Victoria between 1989 and 2008 to compare screening strategies: repeat immunoreactive trypsinogen (IRT) testing (IRT/IRT, 1989-1990), IRT and p.F508del mutation analysis (IRT/p.F508del, 1991-2006) and IRT with analysis of 12 CFTR mutations (IRT/12 mutations, 2007-2008). MAIN OUTCOME MEASURES: Total number of infants screened, people identified with CF (by screening or clinical diagnosis), number of CF-affected terminations of pregnancy, and number of carriers detected. RESULTS: There were 420 people born with CF (live-birth prevalence, 1/3139; 95% CI, 1/2853-1/3462) and 78 CF-affected pregnancy terminations (overall prevalence, 1/2647; 95% CI, 1/2425-1/2896). Of the babies born with CF, 283 (67.4%) were detected by newborn screening alone, 61 (14.5%) had meconium ileus, 33 (7.9%) had a family history of CF, nine (2.1%) were diagnosed antenatally, and 34 (8.1%) were missed by screening (17 missed because IRT level was < 99th percentile, two with repeat IRT level not elevated, 14 without a screened CFTR mutation, and one with missing data). The sensitivities of the protocols were 86.6% for IRT/IRT, 89.9% for IRT/p.F508del, and 95.8% for IRT/12 mutations. Including 12 mutations in the analysis detected one patient who would otherwise have been missed and, had this protocol been implemented from 1989, it would have detected four others. CONCLUSION: Most babies with CF without meconium ileus, a family history or antenatal diagnosis are detected by newborn screening. Despite improved sensitivity with the 12-mutation analysis, most infants detected would have been diagnosed using the IRT/p.F508del protocol.

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30 Where possible, all patients with a diagnosis of CF had further CFTR mutation analysis performed in an attempt to clarify the genotype (p.A455E, p.S549N, p.R347H, p.R1162X, p.R347P, p.R334W, p.R117H). Login to comment

[hide] First study of the F508del mutation in Malaysian c... J Paediatr Child Health. 2011 Aug;47(8):573-5. doi: 10.1111/j.1440-1754.2011.02149.x. Nathan AM, Thong MK, deBruyne J, Ariffin H
First study of the F508del mutation in Malaysian children diagnosed with cystic fibrosis.
J Paediatr Child Health. 2011 Aug;47(8):573-5. doi: 10.1111/j.1440-1754.2011.02149.x., [PMID:21843195]

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48 Letters to the Editor Journal of Paediatrics and Child Health 47 (2011) 572-575 (c) 2011 The Authors Journal of Paediatrics and Child Health (c) 2011 Paediatrics and Child Health Division (Royal Australasian College of Physicians) Table1Summaryoftheclinicalcharacteristics,sweattestresultsandcysticfibrosistransmembraneconductanceregulatormutationstudiesofthepatientsdiagnosedwithcysticfibrosisinUniversity MalayaMedicalCenterfrom2000to2009 PatientAgeat presentation PresentingsymptomsOtherfindingsConsanguinityRaceSweatconductivity (mmol/l) KS score Mutations Rin3monthsRecurrentpneumoniaandFTTPseudo-Bartter`ssyndromeYesIndian13440†Nonedetected Nes8yearsSeverepersistentasthmaFTTNoIndian12450F508del/unknown Abd4monthsSeverepneumoniaandventilator dependent FTTYesYemeni11730F508del/F508del Ben7yearsCirrhosisoftheliverwithportal hypertension FTTUnknown(adopted)Unknown14080†Nonedetected(7T polymorphism) Sak3monthsRecurrentpneumoniaandFTTNDYesIndian11350F508del/F508del Ngan3yearsPseudo-Bartter`ssyndromeNDNoChinese13790Notdone(parentsrefused) LJH5monthsPseudo-Bartter`ssyndromeRecurrentpneumoniaNoChinese/Indonesian9465F508delnegative Josh5monthsPseudo-Bartter`ssyndromeandFTTNDNoIndian8585†Nonedetected Nur3monthsChronicdiarrhoeaandFTTPseudo-Bartter`ssyndromeNoMalay/Chinese13085‡†R553X/nonedetected Vin4monthsRecurrentpneumoniaandFTTNDNoChinese12260F508delnegative Muh5yearsPoorlycontrolledasthmaNDNoMalay10765F508delnegative Naz3monthsFTTandsteatorrhoeaRecurrentlunginfectionsand pseudo-Bartter`s NoMalay14675F508delnegative Additionalmutationsscreenedinthefourpatients:†F508del,I506/7del,G551D,G542X,R553X,R117C,R117H,621+1G>T,V520F,A455E,N1303K,3849+10kbC>T.‡R334W,R347P,A455E,S549N,R560T, 3659delC,W1282X.FTT,failuretothrive;KS,Schwachman-Kulczycki(KS)score;ND,nodata. Login to comment

[hide] The use of DHPLC (Denaturing High Performance Liqu... J Prenat Med. 2010 Jul;4(3):45-8. Mesoraca A, Di Natale M, Cima A, Di Giacomo G, Sarti M, Barone MA, Bizzoco D, Cignini P, Mobili L, D'emidio L, Giorlandino C
The use of DHPLC (Denaturing High Performance Liquid Chromatography) in II level screening of the CFTR gene in Prenatal Diagnosis.
J Prenat Med. 2010 Jul;4(3):45-8., [PMID:22439061]

Abstract [show]
OBJECTIVE: The aim of the study is to evaluate the role of Denaturing High Performance Liquid Chromatography (DHPLC) in the second level screening of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. METHODS: A 9-month prospective study, between June 2008 and March 2009 at Artemisia Fetal Medical Centre, included 3829 samples of amniotic fluid collected from women undergoing mid-trimester amniocentesis.The genetic diagnosis of CF was based on research of the main mutations of the CFTR gene on fetal DNA extracted from the amniocytes, (first level screening) using different commercial diagnostic systems. A second level screening using DHPLC, on the amniotic fluid and on a blood sample from the couple, was offered in case of fetuses heterozygous at first level screening. RESULTS: Of 3829 fetuses, 134 were found to be positive, 129 heterozygous and 5 affected. Of the 129 couples, following appropriate genetic counselling, 53 requested a second level screening. Through the use of DHPLC, 44 couples were found to be negative, and in nine couples, nine rare mutations were identified. CONCLUSIONS: The first level screening can be useful to evidence up to 75% of the CF mutations. The second level screening can identify a further 10% of mutant alleles. DHPLC was found to be a reliable and specific method for the rapid identification of the rare CFTR mutations which were not revealed in initial first level screening.

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100 48 Journal of Prenatal Medicine 2010; 4 (3): 45-50 Table III Mutations found with II level screening through DHPLC Mutations of mutated alleles DF508 29 W1282X 3 N1303K 8 1717-1G®A 2 3659delC 1 G85E 1 2789 +5G®A 2 R553X 2 R1162X 1 R117H 1 G542X 3 Total 53Table I Mutations found through I level screeningMutations analysed with I level screening through OLA CFTR Mutations Position on the CFTR gene DF508 Exon 10 3849+10KbC®T Intron 19 R334W Exon 7 W1282X Exon 10 V520F Exon 10 3905insT Exon 20 N1303K Exon 21 3876delA Exon 20 1717-1G®A Exon 11 3659delC Exon 19 DI507 Exon 10 A455E Exon 9 G85E Exon 3 2789 +5G®A Exon 14 / Intron 14 2183AA®G Exon 13 1898+1G®A Exon 12 / Intron 12 R347P Exon 7 R347H Exon 7 R560T Exon 11 1078delT Exon 7 R553X Exon 11 711+1G®T Exon 5 / Intron 5 G551D Exon 11 R1162X Exon 19 S549R Exon 11 R117H Exon 4 S549N Exon 11 621+1G®T Exon 4 G542X Exon 11 394delTT Exon 3 3120+1G®ðA Exon 16/ Intron 16 2184delA Exon 13 Table II Mutations found through I level screening Mutations Positions on CFTR gene R1066C Exon 17 b L1065P Exon 17 b A1006E Exon 19 R75Q Exon 3 D537E Exon 11 W1134X Exon 18 W1145X Exon 18 L1077P Exon 17b C524X Exon 11 Total 9 The use of DHPLC (Denaturing High Performance Liquid Chromatography) in II level screening of the CFTR gene in Prenatal Diagnosis Journal of Prenatal Medicine 2010; 4 (3): 45-50 49 tion was to provide the couple with adequate counselling in order to better understand the genotype-phenotype correlation in the various associations of mutations. Login to comment

[hide] An immunocytochemical assay to detect human CFTR e... Mol Cell Probes. 2009 Dec;23(6):272-80. Epub 2009 Jul 15. Davidson H, Wilson A, Gray RD, Horsley A, Pringle IA, McLachlan G, Nairn AC, Stearns C, Gibson J, Holder E, Jones L, Doherty A, Coles R, Sumner-Jones SG, Wasowicz M, Manvell M, Griesenbach U, Hyde SC, Gill DR, Davies J, Collie DD, Alton EW, Porteous DJ, Boyd AC
An immunocytochemical assay to detect human CFTR expression following gene transfer.
Mol Cell Probes. 2009 Dec;23(6):272-80. Epub 2009 Jul 15., [PMID:19615439]

Abstract [show]
BACKGROUND: To assess gene therapy treatment for cystic fibrosis (CF) in clinical trials it is essential to develop robust assays that can accurately detect transgene expression in human airway epithelial cells. Our aim was to develop a reproducible immunocytochemical assay for human CFTR protein which can measure both endogenous CFTR levels and augmented CFTR expression after gene delivery. METHODS: We characterised an antibody (G449) which satisfied the criteria for use in clinical trials. We optimised our immunocytochemistry method and identified G449 dilutions at which endogenous CFTR levels were negligible in CF samples, thus enhancing detection of transgenic CFTR protein. After developing a transfection technique for brushed human nasal epithelial cells, we transfected non-CF and CF cells with a clinically relevant CpG-free plasmid encoding human CFTR. RESULTS: The optimised immunocytochemistry method gave improved discrimination between CF and non-CF samples. Transfection of a CFTR expression vector into primary nasal epithelial cells resulted in detectable RNA and protein expression. CFTR protein was present in 0.05-10% of non-CF cells and 0.02-0.8% of CF cells. CONCLUSION: We have developed a sensitive, clinically relevant immunocytochemical assay for CFTR protein and have used it to detect transgene-expressed CFTR in transfected human primary airway epithelial cells.

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215 CF genotypes for nasal brushings were 15 DF508/DF508, 2 DF508/ND, 1 DF508/A455E, 1 DF508/G551D, 1 G85E/ND, 1 ND/ND (where 'ND` indicates that none of the 31 most common mutations was detected). Login to comment
218 CF genotypes for nasal brushings were 15 DF508/DF508, 2 DF508/ND, 1 DF508/A455E, 1 DF508/G551D, 1 G85E/ND, 1 ND/ND (where 'ND` indicates that none of the 31 most common mutations was detected). Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... J Hepatol. 2009 Jan;50(1):150-7. Epub 2008 Oct 7. Henckaerts L, Jaspers M, Van Steenbergen W, Vliegen L, Fevery J, Nuytten H, Roskams T, Rutgeerts P, Cassiman JJ, Vermeire S, Cuppens H
Cystic fibrosis transmembrane conductance regulator gene polymorphisms in patients with primary sclerosing cholangitis.
J Hepatol. 2009 Jan;50(1):150-7. Epub 2008 Oct 7., [PMID:18992954]

Abstract [show]
BACKGROUND/AIMS: Primary sclerosing cholangitis (PSC) is a progressive cholestatic disease commonly associated with inflammatory bowel disease (IBD) and characterized by fibrosing inflammatory destruction of bile ducts. The histological features in the liver of PSC patients are similar to those observed in cystic fibrosis (CF). Our aim was to study whether variants in the CFTR gene are associated with the occurrence and/or evolution of PSC. METHODS: PSC patients (n=140) were genotyped for F508del, the TGmTn variants, and four additional polymorphic loci (1001+11 C>T, M470V, T854T and Q1463Q), and compared to 136 matched healthy controls. RESULTS: The 1540G-allele, encoding V470, was less frequent in PSC (52%) than in controls (64%, p=0.003), and was associated with protection against PSC in individuals without IBD (OR 0.25, 95% CI 0.12-0.52, p=0.0002). Also TG11-T7 was less frequent in PSC (53%) than in controls (61%, p=0.04), this haplotype was associated with reduced risk for PSC (OR 0.34, 95% CI 0.17-0.70, p=0.003) in individuals without IBD. CONCLUSIONS: In this cohort of PSC patients, several CFTR-variants affecting the functional properties of the CFTR protein seem to offer protection against the development of PSC, confirming our hypothesis that CFTR might be implicated in the pathogenesis of PSC.

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91 There was Table 4 Summary of the 37 CFTR variants studied in the exploratory phase INNO-LiPA CFTR 19 INNO-LiPA CFTR17+Tn Update F508del 621+1GfiT G542X 3849+10kbCfiT N1303K 2183AAfiG W1282X 394delTT G551D 2789+5GfiA 1717-1GfiA R1162X R553X 3659delC CFTRdele2,3(21kb) R117H I507del R334W 711+1GfiT R347P 3272-26AfiG G85E 3905insT 1078delT R560T A455E 1898+1GfiA 2143delT S1251N E60X I148T 2184delA 3199del6 711+5GfiA 3120+1GfiA Tn Q552X Fig. 1. Login to comment

[hide] Cystic fibrosis carrier frequency and estimated pr... J Cyst Fibros. 2008 Sep;7(5):440-3. Epub 2008 Feb 1. Ratbi I, Genin E, Legendre M, Le Floch A, Costa C, Cherkaoui-Deqqaqi S, Goossens M, Sefiani A, Girodon E
Cystic fibrosis carrier frequency and estimated prevalence of the disease in Morocco.
J Cyst Fibros. 2008 Sep;7(5):440-3. Epub 2008 Feb 1., [PMID:18243066]

Abstract [show]
BACKGROUND: The epidemiology of cystic fibrosis (CF) is poorly known in North African populations, in particular in Morocco and the CF carrier frequency in the general Moroccan population has never been evaluated. METHODS: To estimate the prevalence of CF mutations in Morocco, blood samples from 150 healthy Moroccans were tested for frequent CFTR mutations and the intron 8 polyT variant. RESULTS: Two subjects were heterozygous for F508del and eight others for the (T)5 variant. CONCLUSION: These findings indicate that the Moroccan population is at risk for CF and CFTR-related disorders. CF prevalence could be in the range of that found in European populations. Wider studies are necessary to identify the clinical pattern and accurately determine the prevalence and molecular basis of CF in Morocco.

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27 We screened for 32 CFTR gene mutations (G85E, 394delTT, R117H, 621+1GNT, 711+1GNT, R334W, R347P, R347H, 1078delT, A455E, I507del, F508del, V520F, 1717-1GNA, G542X, G551D, R553X, R560T, S549R(TNG), S549N, 1898+1GNA, 2183AANG, 2184delA, 2789+5GNA, 3120 + 1G NA, R1162X, 3659delC, 3849 + 10kbC NT, W1282X, 3905insT, 3876delA, N1303K) and the (T)5 splicing variant of intron 8, using a commercial kit (CF v3 Genotyping Assay, Abbott, Rungis, France). Login to comment

[hide] Validation of high-resolution DNA melting analysis... J Mol Diagn. 2008 Sep;10(5):424-34. Epub 2008 Aug 7. Audrezet MP, Dabricot A, Le Marechal C, Ferec C
Validation of high-resolution DNA melting analysis for mutation scanning of the cystic fibrosis transmembrane conductance regulator (CFTR) gene.
J Mol Diagn. 2008 Sep;10(5):424-34. Epub 2008 Aug 7., [PMID:18687795]

Abstract [show]
High-resolution melting analysis of polymerase chain reaction products for mutation scanning, which began in the early 2000s, is based on monitoring of the fluorescence released during the melting of double-stranded DNA labeled with specifically developed saturation dye, such as LC-Green. We report here the validation of this method to scan 98% of the coding sequence of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. We designed 32 pairs of primers to amplify and analyze the 27 exons of the gene. Thanks to the addition of a small GC-clamp at the 5' ends of the primers, one single melting domain and one identical annealing temperature were obtained to co-amplify all of the fragments. A total of 307 DNA samples, extracted by the salt precipitation method, carrying 221 mutations and 21 polymorphisms, plus 20 control samples free from variations (confirmed by denaturing high-performance liquid chromatography analysis), was used. With the conditions described in this study, 100% of samples that carry heterozygous mutations and 60% of those with homozygous mutations were identified. The study of a cohort of 136 idiopathic chronic pancreatitis patients enabled us to prospectively evaluate this technique. Thus, high-resolution melting analysis is a robust and sensitive single-tube technique for screening mutations in a gene and promises to become the gold standard over denaturing high-performance liquid chromatography, particularly for highly mutated genes such as CFTR, and appears suitable for use in reference diagnostic laboratories.

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51 Sequences of the Primers Used for CFTR Analysis by HRM, GC Size, Amplicon Length, Number of Positive Controls Validated for Each Exon, and Positive Controls for Routine Analysis Exon Primer Sequences GC length Amplicon length (bp) Introns Number of heterozygous- positive controls Number of homozygous- positive controls Recommended control 1 LSCFE1Fmod 5Ј-CCGCCGCCGTTGAGCGGCAGGCACC-3Ј 8 200 bp 74 4 125GϾC LSCFE1Rmod 5Ј-CCGCCGCCGGCACGTGTCTTT CCGAAGCT-3Ј 8 19 M1I 2 2i5b 5Ј-CAAATCTGTATGGAGACC-3Ј 0 194 bp 39 5 R31C 2i3Љ 5Ј-CAACTAAACAATGTACATGAAC-3Ј 0 4 296ϩ1GϾT 3 LSCFe3Fmod LSCFe3Rmod 5Ј-CGCCGTTAAGGGAAATAGGACAA CTAAAATA-3Ј 5 276 bp 44 10 2 R75Q 5Ј-CCGCCGATTCACCAGATTTCGTAGTC-3Ј 6 66 G85V 4 LSCFe4FmodC 5Ј-CCGCCGCCGCCCGTGTTGAAATT CTCAGGGT-3Ј 12 361 bp 52 14 1 R117H LSCFe4RmodC 5Ј-CCGCCGCCCACATGTACGATAC AGAATATATGTGCC-3Ј 9 26 574delA 5 LSCFE5Fmod 5Ј-CCGCCGGTTGAAATTATCTAACTTTCC-3Ј 6 201 bp 13 8 624delT LSCFE5Rmod 5Ј-CCGAACTCCGCCTTTCCAGTTGT-3Ј 3 48 711ϩ1GϾT 6a LSCF6aFmod2 5Ј-CCGCCGGGGTGGAAGAT ACAATGACACCTG-3Ј 5 317 bp 25 8 C225X LSCF6aRmod2 5Ј-CCGCCGCCGCGATGCATAGAG CAGTCCTGGTT-3Ј 11 66 L206W 6b LSCFE6bFmod 5Ј-CGCGCCGCCGGATTTAC AGAGATCAGAGAG-3Ј 10 239 bp 0 2 1 R258G LSCFE6Brmod 5Ј-CCGCCGCCGAGGTGGA GTCTACCATGA-3Ј 8 66 1001ϩ11CϾT 7 LSCFE7Fmod2 5Ј-CCGCCGCCCTCTCCCTGAATTT TATTGTTATTGTTT-3Ј 13 326 bp 7 11 1078delT LSCFE7Rmod2 5Ј-CCCGCCGCCCTATAATGCAG CATTATGGT-3Ј 10 7 1248ϩ1GϾT 8 LSCFE8Fmod 5Ј-CCGGAATGCATTAATGCTAT TCTGATTC-3Ј 4 199 bp 32 7 W401X LSCFE8Rmod 5Ј-CCCGCAGTTAGGTGTTTAG AGCAAACAA-3Ј 4 18 1249-5AϾG 9 LSCFe9Fmod2 5Ј-CCGCCGCCGGGAATTATTTGAGAA AGCAAAACA-3Ј 8 279 bp 0 3 D443Y LSCFe9Rmod2 5Ј-CCGCCGCGAAAATACCTTCCAG CACTACAAACTAGAAA-3Ј 8 57 A455E 10 LSCF10FmodD 5Ј-CGCCGTTATGGGAGAACTGG AGCCTTCAGAG-3Ј 5 275 bp 0 15 1 F508del LSCF10RmodD 5Ј-CCGCAGACTAACCGATTGAAT ATGGAGCC-3Ј 4 68 E528E 11 h11i5 5Ј-TGCCTTTCAAATTCAGATTGAGC-3Ј 0 197 bp 42 13 2 G542X 11i3ter 5Ј-ACAGCAAATGCTTGCTAGACC-3Ј 0 17 G551D 12 LSCFE12Fmod 5Ј-CGCGTCATCTACACTAGATGACCAG-3Ј 4 244 bp 43 15 G576A 1898 ϩ 1GϾALSCFE12Rmod 5Ј-CCGGAGGTAAAATGCAATCTATGATG-3Ј 3 63 13 LSCF13AFmod 5Ј-CCGCCGCCGGAGACATATTG CAATAAAGTAT-3Ј 9 38 20 I601F LSCF13ARmod 5Ј-GCCTGTCCAGGAGACAGGA GCATCTC-3Ј 2 R668C LSCF13BFmod 5Ј-CCGCCGCAATCCTAACTGAG ACCTTACACCG-3Ј 2 R668C LSCF13BRmod 5Ј-CCGCCGATCAGGTTCAGGA CAGACTGC-3Ј 3 346 bp 2184insA LSCF13CFmod 5Ј-CCGCGGTGATCAGCACTGGCCC-3Ј 6 301 bp 77 L749L LSCF13CRmod 5Ј-CCGCGCGCGCGGCCAGTTTCTTG AGATAACCTTCT-3Ј 13 259 bp V754M LSCF13DFmod 5Ј-CGTGTCACTGGCCCCTCAGGC-3Ј 1 221 bp I807M LSCF13DRmof 5Ј-CCGCCGCCGCTAATCCTATGA TTTTAGTAAAT-3Ј 9 220 bp 2622ϩ1GϾA LSCf13FFmod 5Ј-CGCGGTGCAGAAAGAAGAAAT TCAATCCTAACTG-3Ј 4 R668C LSCF13FRmod 5Ј-CCGCCGTGCCATTCATTTGT AAGGGAGTCT-3Ј 6 2184insA 14a LSCF14aFmodB 5Ј-CCGACCACAATGGTGGCAT GAAACTG-3Ј 3 239 bp 35 7 1 T854T LSCF14aRmodB 5Ј-CCGCCGACTTTAAATCCAGTAAT ACTTTACAATAGAACA-3Ј 6 7 W846X 14b LSCF14bFmod 5Ј-CCGGAGGAATAGGTGAAGAT-3Ј 2 179 bp 38 4 2752-5GϾT LSCF14bRmodb 5Ј-CCGTACATACAAACATAGTGGATT-3Ј 3 59 2789ϩ5GϾT 15 LSCFE15Fmod 5Ј-CGCGCCGTGTATTGGAAA TTCAGTAAGTAACTTTGG-3Ј 7 412 bp 33 16 T908S LSCFE15Rmod 5Ј-CCGCAGCCAGCACTGCCAT TAGAAA-3Ј 4 68 S945L (table continues) phisms that we have chosen to exclude. Login to comment

[hide] Consensus on the use and interpretation of cystic ... J Cyst Fibros. 2008 May;7(3):179-96. Castellani C, Cuppens H, Macek M Jr, Cassiman JJ, Kerem E, Durie P, Tullis E, Assael BM, Bombieri C, Brown A, Casals T, Claustres M, Cutting GR, Dequeker E, Dodge J, Doull I, Farrell P, Ferec C, Girodon E, Johannesson M, Kerem B, Knowles M, Munck A, Pignatti PF, Radojkovic D, Rizzotti P, Schwarz M, Stuhrmann M, Tzetis M, Zielenski J, Elborn JS
Consensus on the use and interpretation of cystic fibrosis mutation analysis in clinical practice.
J Cyst Fibros. 2008 May;7(3):179-96., [PMID:18456578]

Abstract [show]
It is often challenging for the clinician interested in cystic fibrosis (CF) to interpret molecular genetic results, and to integrate them in the diagnostic process. The limitations of genotyping technology, the choice of mutations to be tested, and the clinical context in which the test is administered can all influence how genetic information is interpreted. This paper describes the conclusions of a consensus conference to address the use and interpretation of CF mutation analysis in clinical settings. Although the diagnosis of CF is usually straightforward, care needs to be exercised in the use and interpretation of genetic tests: genotype information is not the final arbiter of a clinical diagnosis of CF or CF transmembrane conductance regulator (CFTR) protein related disorders. The diagnosis of these conditions is primarily based on the clinical presentation, and is supported by evaluation of CFTR function (sweat testing, nasal potential difference) and genetic analysis. None of these features are sufficient on their own to make a diagnosis of CF or CFTR-related disorders. Broad genotype/phenotype associations are useful in epidemiological studies, but CFTR genotype does not accurately predict individual outcome. The use of CFTR genotype for prediction of prognosis in people with CF at the time of their diagnosis is not recommended. The importance of communication between clinicians and medical genetic laboratories is emphasized. The results of testing and their implications should be reported in a manner understandable to the clinicians caring for CF patients.

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1236 Table 1 Geographical distribution of the most common mutations E60X Southern European S549N Indian CFTR Slavic - Eastern European G551D United Kingdom, Central Europe R75X Southern European, US-Hispanic Q552X Southern European, Italian 394delTT Nordic - Baltic sea region R553X Central European G85E Southern Europe A559T African-American 406-1GNA US-Hispanic R560T Northern Irish R117H European-derived populations 1811+1.6kbANG Spanish, US-Hispanic R117C Northern European 1898+1GNA United Kingdom, Central Europe 621+1GNT Southern European 1898+5GNT East Asian populations 711+1GNT French, French Canadian 2143delT Slavic - Eastern European 711+5GNA US-Hispanic 2183delAANG Southern Europe, Middle Eastern, Iranian, Latin American L206W Spanish and US-Hispanic 2184delA European-derived populations V232D Spanish and US-Hispanic 2789+5GNA European-derived populations 1078delT French Brittany Q890X Southern European R334W Southern European, Latin American 3120+1GNA African, Arabian, African-American, Southern Europe 1161delC Indian 3272-26ANG European-derived populations R347P European-derived, Latin America 3659delC Scandinavian R347H Turkish 3849+10kbCNT Ashkenazi-Jewish, Southern European, Middle Eastern, Iranian, Indian A455E Dutch R1066C Southern European 1609delCA Spanish, US-Hispanic Y1092X (CNA) Southern European I506T Southern European, Spanish M1101K US-Hutterite I507del European-derived populations 3905insT Swiss F508del European-derived populations D1152H European-derived populations 1677delTA Southern European, Middle Eastern R1158X Southern European 1717-GNA European-derived populations R1162X Italian, Amerindian, Latin America V520F Irish S1251N European-derived populations G542X Southern European, Mediterranean W1282X Ashkenazi-Jewish, Middle Eastern S549R(TNG) Middle Eastern N1303K Southern European, Middle Eastern Legend: these alleles occur with a frequency superior to 0.1% in selected populations. Login to comment
1239 Table 1 Geographical distribution of the most common mutations E60X Southern European S549N Indian CFTR Slavic - Eastern European G551D United Kingdom, Central Europe R75X Southern European, US-Hispanic Q552X Southern European, Italian 394delTT Nordic - Baltic sea region R553X Central European G85E Southern Europe A559T African-American 406-1GNA US-Hispanic R560T Northern Irish R117H European-derived populations 1811+1.6kbANG Spanish, US-Hispanic R117C Northern European 1898+1GNA United Kingdom, Central Europe 621+1GNT Southern European 1898+5GNT East Asian populations 711+1GNT French, French Canadian 2143delT Slavic - Eastern European 711+5GNA US-Hispanic 2183delAANG Southern Europe, Middle Eastern, Iranian, Latin American L206W Spanish and US-Hispanic 2184delA European-derived populations V232D Spanish and US-Hispanic 2789+5GNA European-derived populations 1078delT French Brittany Q890X Southern European R334W Southern European, Latin American 3120+1GNA African, Arabian, African-American, Southern Europe 1161delC Indian 3272-26ANG European-derived populations R347P European-derived, Latin America 3659delC Scandinavian R347H Turkish 3849+10kbCNT Ashkenazi-Jewish, Southern European, Middle Eastern, Iranian, Indian A455E Dutch R1066C Southern European 1609delCA Spanish, US-Hispanic Y1092X (CNA) Southern European I506T Southern European, Spanish M1101K US-Hutterite I507del European-derived populations 3905insT Swiss F508del European-derived populations D1152H European-derived populations 1677delTA Southern European, Middle Eastern R1158X Southern European 1717-GNA European-derived populations R1162X Italian, Amerindian, Latin America V520F Irish S1251N European-derived populations G542X Southern European, Mediterranean W1282X Ashkenazi-Jewish, Middle Eastern S549R(TNG) Middle Eastern N1303K Southern European, Middle Eastern Legend: these alleles occur with a frequency superior to 0.1% in selected populations. Login to comment

[hide] High incidence of the CFTR mutations 3272-26A-->G ... J Cyst Fibros. 2007 Nov 30;6(6):371-5. Epub 2007 May 3. Storm K, Moens E, Vits L, De Vlieger H, Delaere G, D'Hollander M, Wuyts W, Biervliet M, Van Schil L, Desager K, Nothen MM
High incidence of the CFTR mutations 3272-26A-->G and L927P in Belgian cystic fibrosis patients, and identification of three new CFTR mutations (186-2A-->G, E588V, and 1671insTATCA).
J Cyst Fibros. 2007 Nov 30;6(6):371-5. Epub 2007 May 3., [PMID:17481968]

Abstract [show]
We have analyzed 143 unrelated Belgian patients with a positive diagnosis of cystic fibrosis (CF) for mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. An initial screening for 29 CFTR mutations led to mutation identification in 89.9% of the tested chromosomes. Subsequently an extensive analysis of the CFTR gene was performed by denaturating gradient gel electrophoresis (DGGE) in those patients with at least one unknown mutation after preliminary screening. In addition to 10 previously reported mutations we identified 2 new mutations 186-2A-->G and E588V. A third new mutation 1671insTATCA was identified during routine screening for DeltaF508. Two mutations were detected with a higher frequency than expected: 3272-26A-->G, which is the second most common mutation after DeltaF508 in our CF population with a frequency of 3.8%, and L927P (2.4%). The clinical data is presented for the mutations 186-2A-->G, E588V, 3272-26A-->G and L927P. The mutation data are useful for the Belgian population to supplement the initial screening set of mutations.

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32 The Inno Lipa™ CFTR17 assay contains normal and mutant probes for 17 other CFTR mutations (394delTT, G85E, 621+1G→T, R117H, 1078delT, R347P, R334W, E60X, 711+5G→A, 2789 + 5G→ A, R1162X, 3659delC, 3849 + 10kbC→ T, 2143delT, A455E, 2183AA→G, 2184delA) (Innogenetics). Login to comment

[hide] Mutational spectrum of cystic fibrosis patients fr... Mol Genet Metab. 2006 Apr;87(4):370-5. Epub 2006 Jan 19. Ramirez AM, Ramos MD, Jimenez J, Ghio A, de Botelli MM, Rezzonico CA, Marques I, Pereyro S, Casals T, de Kremer RD
Mutational spectrum of cystic fibrosis patients from Cordoba province and its zone of influence: implications of molecular diagnosis in Argentina.
Mol Genet Metab. 2006 Apr;87(4):370-5. Epub 2006 Jan 19., [PMID:16423550]

Abstract [show]
Cystic Fibrosis (CF) is an autosomal recessive disorder affecting 1/2000-4000 newborns in Caucasian populations. This lethal disease mainly affects respiratory and digestive organs as well as fertility in man. So far, the CF prevalence and mutational spectrum have showed specificity among populations and regions, making it necessary to establish them in each one. In this study, we present the spectrum and frequency of CFTR gene mutations in CF patients from Cordoba (a province with 3.1 millions inhabitants in the middle of Argentina) and its zone of influence, to offer an accurate genetic testing. The study includes 78 families in which 98 patients fulfilled clinical criteria to CF diagnosis. The strategy for the molecular diagnosis comprised analysis of 21 common mutations, microsatellite haplotypes and the complete CFTR gene analysis using scanning techniques followed by sequencing of the abnormal migration patterns. Our first step led us to the identification of 10 mutations that represented 76% of alleles. Another four mutations (p.R1066C, c.1811 + 1.6 kbA > G, c.711 + 1G > T, and p.G85E) were found based on the microsatellite haplotype-mutation association. Finally, 14 mutations were characterized after the CFTR gene scanning, three of them are not previously described (p.G27R, c.622-2A > G, and p.W277R). In summary, we have identified 27 mutations accounting for 94.23% of CF alleles. This characteristic mutational spectrum highlights the 14 most frequent mutations (>1%) in the Cordoba region.

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44 Mutations (p.F508del, p.N1303K, p.G542X, p.R334W, c.2789 + 5G > A, c.3659delC, p.R553X, c.3849 + 10kbC > T, p.R1162X, c.621 + 1G > T, p.W1282X, p.R117H, c.1078delT, p.E60X, p.R347P, p.A455E, p.I507del, c.1717-1G > A, p.G551D, [c.2183A > G; c.2184delA] and p.S1251N) were analyzed by heteroduplex analysis on polyacrylamide gel electrophoresis [11,12] and by ampliWcation refractory mutation system [13] in all 78 patients. Login to comment

[hide] TDP43 depletion rescues aberrant CFTR exon 9 skipp... FEBS Lett. 2006 Feb 20;580(5):1339-44. Epub 2006 Jan 26. Ayala YM, Pagani F, Baralle FE
TDP43 depletion rescues aberrant CFTR exon 9 skipping.
FEBS Lett. 2006 Feb 20;580(5):1339-44. Epub 2006 Jan 26., [PMID:16458894]

Abstract [show]
CFTR exon 9 presents a 3' splice site polymorphism, (UG)mU(n), whose composition influences splicing. TDP43 specifically binds the UG tract of the transcript and inhibits splicing in vitro. We report that depletion of TDP43 through RNA interference removes splicing inhibition caused by unfavorable (UG)mU(n) sequences, indicating that TDP43 exerts a potent inhibitory effect in vivo. We also show that the UG-TDP43 interaction has a dominant role over other exon 9 splicing regulatory elements. These results suggest that TDP43 association near a splice site has determined the evolution of positive splicing regulatory elements to contrast this inhibition.

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13 Among these are mutations in composite exonic regulatory elements of splicing (CERES) that disrupt positive regulatory elements and thus result in exon skipping (e.g., A455E) [5]. Login to comment
95 One of the positive elements, found in the exon, can be affected by a naturally occurring mutation associated with CF (A455E). Login to comment
147 Therefore, TDP43 downregulation would also improve CFTR expression in cases of positive splicing element disruption, such as in the A455E (C1496A) mutation. Login to comment
94 One of the positive elements, found in the exon, can be affected by a naturally occurring mutation associated with CF (A455E). Login to comment
146 Therefore, TDP43 downregulation would also improve CFTR expression in cases of positive splicing element disruption, such as in the A455E (C1496A) mutation. Login to comment

[hide] Cytogenetic analysis of azoospermic patients: kary... Eur J Obstet Gynecol Reprod Biol. 2006 Feb 1;124(2):197-203. Epub 2005 Sep 12. Stipoljev F, Vujisic S, Parazajder J, Hafner D, Jezek D, Sertic J
Cytogenetic analysis of azoospermic patients: karyotype comparison of peripheral blood lymphocytes and testicular tissue.
Eur J Obstet Gynecol Reprod Biol. 2006 Feb 1;124(2):197-203. Epub 2005 Sep 12., [PMID:16157443]

Abstract [show]
OBJECTIVE: The objective was to compare the results of a complete chromosomal, genetic and histological investigation in 13 azoospermic men with the results of the intracytoplasmic sperm injection (ICSI) procedure. STUDY DESIGN: Peripheral blood samples were used for the measurement of follicle-stimulating hormone (FSH) levels, chromosomal analysis, microdeletions in the azoospermia factor (AZF) region of the Y chromosome and cystic fibrosis transmembrane conductance regulator (CFTR) mutation analysis. Testicular tissue was used for histological scoring and cytogenetic evaluation. RESULTS: Peripheral blood cytogenetic analysis revealed a normal male karyotype in all cases. Chromosomal analysis from testicular tissue revealed a mosaicism for the terminal deletion of chromosome 22 with a breakpoint site at 22q13 in one patient with congenital bilateral absence of the vas deferens (CBAVD). Deletions in the AZFa, ATFb, and AZFc regions were not detected. The CFTR mutational analysis showed normal results in all patients. CONCLUSIONS: Cytogenetic evaluation of testicular tissue should be performed in non-obstructive and obstructive azoospermic patients as well as in patients with multiple failed IVF and recurrent spontaneous abortion.

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64 T; intron 8/exon 9: A455E, 5T/7T/9T and LightCycler-based fluorescent-labeled oligonucleotide melting assays (DF508) [5]. Login to comment

[hide] New tests for cystic fibrosis. Paediatr Respir Rev. 2006;7 Suppl 1:S141-3. Epub 2006 Jun 5. Davies JC
New tests for cystic fibrosis.
Paediatr Respir Rev. 2006;7 Suppl 1:S141-3. Epub 2006 Jun 5., [PMID:16798543]

Abstract [show]
Most patients presenting with symptoms and signs of CF are still diagnosed on the basis of a sweat test. CFTR mutation analysis is useful in confirming the diagnosis, screening family members, newborn screening programmes and in those with borderline or normal sweat tests with a high index of suspicion. Nasal PD can also be helpful in the latter group, although there are a number of caveats to its use and interpretation.

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46 A very small number of mutations which appear to confer a mild pulmonary phenotype have been described, such as A455E and R117H. Login to comment

[hide] Spectrum of mutations in CFTR in Finland: 18 years... J Cyst Fibros. 2005 Dec;4(4):233-7. Epub 2005 Jul 26. Kinnunen S, Bonache S, Casals T, Monto S, Savilahti E, Kere J, Jarvela I
Spectrum of mutations in CFTR in Finland: 18 years follow-up study and identification of two novel mutations.
J Cyst Fibros. 2005 Dec;4(4):233-7. Epub 2005 Jul 26., [PMID:16051530]

Abstract [show]
BACKGROUND: The incidence of cystic fibrosis (CF) is low in the isolated Finnish population and the Finnish CF mutation spectrum has differed from many European countries. METHODS: We have analyzed the mutation spectrum and the geographical distribution of CF mutations in Finland covering the last 18 years (1987-2004). RESULTS: A total of 14 mutations were identified; two of them new, 774insT and S589T (G>C at 1,898). The overall coverage of mutations was 97% (99/102 chromosomes). The most frequent mutations were F508del and 394delTT, found in 36% (37/102) and 35% (36/102) of the CF chromosomes respectively. Of the rare mutations, a mutation of presumable Slavic origin, CFTRdele2.3 (21 kb), was enriched in a rural isolate with a frequency of 5,9% (6/102), and a mutation that possibly indicates Swedish influence, 3659delC, was scattered throughout the country with a similar frequency of 5,9% (6/102). G542X, R1162X, R117H, 3732delA, 1,898 + 3A >C, S1196X, S945L, W57R, 774insT and S589T were each identified in a number of chromosomes from one to three. CONCLUSIONS: Our observations of the Finnish CF mutation spectrum fit well with the characteristics of Finland as a population of multiple local founder effects.

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36 The InnoLipa assay recognizes 36 mutations: E60X (c.178G>T, p.Glu60X), G85E (c.254G>A, p.Gly85- Glu), 394delTT, R117H (c.350G>A, p.Arg117His), I148T (c.443T>C, p.Ile148Thr), 621+1G>T (c.489+1G>T), 711+1G>T (c.579+1G>T), 711+5G>A (c.579+5G>A), 1078delT (c.948delT, p.Phe316fs), R334W (c.1000C>T, p.Arg334Trp), R347P (c.1040G>C, p.Arg347Pro), A455E (c.1364C>A, p.Ala455Glu), I507del (c.1519_1521delATC, p.Ile507del), F508del, 1717À1G>A (c.1585À1G>A), G542X, G551D (c.1652G >A, p.Gly551Asp), Q552X (c.1654C > T, p.Gln552X), R553X (c.1657C > T, p.Arg553X), R560T (1679G>vC, p.Arg560Thr), 1898+ 1G > A (c.1766 + 1G > A), 2143delT (c.2012delT, p.Leu671fs), 2183AA > G (c.2051_2052delAAinsG, p.Lys684fs), 2184delA (c.2052delA, p.Lys684fs), 2789+ 5G>A (c.2657+5G>A), 3120+1G>A (c.2988+1G>A), 3199del6 (c.3067_3072del, p.Ile1023_Val1024del), 3272À 26A > G (c.3140 À26A > G), R1162X (c.3484C > T, p.Arg1162X), 3849+10kbCYT, 3659delC (c.3528delC, p.Lys1177fs), S1251N (c.3752G > A, p.Ser1251Asn), 3905insT (c.3773dupT, p.Leu1258fs), W1282X (c.3846G> A, p.Trp1282X), N1303K (c.3909C>G, p.Asn1303Lys), CFTRdele2,3(21kb) and Tn-polymorphism on intron 8. Login to comment
37 The InnoLipa assay recognizes 36 mutations: E60X (c.178G>T, p.Glu60X), G85E (c.254G>A, p.Gly85Glu), 394delTT, R117H (c.350G>A, p.Arg117His), I148T (c.443T>C, p.Ile148Thr), 621+1G>T (c.489+1G>T), 711+1G>T (c.579+1G>T), 711+5G>A (c.579+5G>A), 1078delT (c.948delT, p.Phe316fs), R334W (c.1000C>T, p.Arg334Trp), R347P (c.1040G>C, p.Arg347Pro), A455E (c.1364C>A, p.Ala455Glu), I507del (c.1519_1521delATC, p.Ile507del), F508del, 1717 1G>A (c.1585 1G>A), G542X, G551D (c.1652G >A, p.Gly551Asp), Q552X (c.1654C > T, p.Gln552X), R553X (c.1657C > T, p.Arg553X), R560T (1679G>vC, p.Arg560Thr), 1898+ 1G > A (c.1766 + 1G > A), 2143delT (c.2012delT, p.Leu671fs), 2183AA > G (c.2051_2052delAAinsG, p.Lys684fs), 2184delA (c.2052delA, p.Lys684fs), 2789+ 5G>A (c.2657+5G>A), 3120+1G>A (c.2988+1G>A), 3199del6 (c.3067_3072del, p.Ile1023_Val1024del), 3272 26A > G (c.3140 26A > G), R1162X (c.3484C > T, p.Arg1162X), 3849+10kbCYT, 3659delC (c.3528delC, p.Lys1177fs), S1251N (c.3752G > A, p.Ser1251Asn), 3905insT (c.3773dupT, p.Leu1258fs), W1282X (c.3846G> A, p.Trp1282X), N1303K (c.3909C>G, p.Asn1303Lys), CFTRdele2,3(21kb) and Tn-polymorphism on intron 8. Login to comment

[hide] Hyperechogenic fetal bowel: counseling difficultie... Eur J Med Genet. 2005 Oct-Dec;48(4):421-5. Marcus-Soekarman D, Offermans J, Van den Ouweland AM, Mulder AL, Muntjewerff N, Vossen M, Kleijer W, Schrander-Stumpel C, Dooijes D
Hyperechogenic fetal bowel: counseling difficulties.
Eur J Med Genet. 2005 Oct-Dec;48(4):421-5., [PMID:16378926]

Abstract [show]
The detection of echodense fetal bowel on ultrasound examination in the second trimester of pregnancy justifies invasive procedures such as amniocentesis to detect an underlying cause. We present a case in which initial tests identified only one mutation in the cystic fibrosis transmembrane regulator (CFTR)-gene of the fetus, the family history being negative for CF. Strongly reduced intestinal enzyme activities suggested intestinal obstruction and further increased the estimated risk for CF. After the 24th gestational week, a second mutation was found, confirming cystic fibrosis in this child. Problems in counseling in this particular case are discussed.

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67 Routine CFTR-mutation analysis, using Table 1 CFTR-mutations screened for in the first step E60X 2143delT G542X G85E 2183AA-G G551D 394delTT 2184delA Q552X 621 + 1G-T 2789 + 5G-A R553X R117H 3849 + 10kbC-T R560T 711 + 5G-A R1162X S1251N 1078delT 3659delC 390insT R334W delta I507 W1282X R347P delta F508 N1303K A455E 1717-1G-A a panel of 29 CFTR-mutations, detects only 41.6% of CFTR-mutations in the Turkish population [1]. Login to comment

[hide] Genotyping microarray for the detection of more th... J Mol Diagn. 2005 Aug;7(3):375-87. Schrijver I, Oitmaa E, Metspalu A, Gardner P
Genotyping microarray for the detection of more than 200 CFTR mutations in ethnically diverse populations.
J Mol Diagn. 2005 Aug;7(3):375-87., [PMID:16049310]

Abstract [show]
Cystic fibrosis (CF), which is due to mutations in the cystic fibrosis transmembrane conductance regulator gene, is a common life-shortening disease. Although CF occurs with the highest incidence in Caucasians, it also occurs in other ethnicities with variable frequency. Recent national guidelines suggest that all couples contemplating pregnancy should be informed of molecular screening for CF carrier status for purposes of genetic counseling. Commercially available CF carrier screening panels offer a limited panel of mutations, however, making them insufficiently sensitive for certain groups within an ethnically diverse population. This discrepancy is even more pronounced when such carrier screening panels are used for diagnostic purposes. By means of arrayed primer extension technology, we have designed a genotyping microarray with 204 probe sites for CF transmembrane conductance regulator gene mutation detection. The arrayed primer extension array, based on a platform technology for disease detection with multiple applications, is a robust, cost-effective, and easily modifiable assay suitable for CF carrier screening and disease detection.

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51 Complete List of Mutations Detectable with the CF APEX Assay CFTR location Amino acid change Nucleotide change 1 E 1 Frameshift 175delC 2 E 2,3 Frameshift del E2, E3 3 E 2 W19C 189 GϾT 4 E 2 Q39X 247 CϾT 5 IVS 2 Possible splicing defect 296 ϩ 12 TϾC 6 E 3 Frameshift 359insT 7 E 3 Frameshift 394delTT 8 E 3 W57X (TAG) 302GϾA 9 E 3 W57X (TGA) 303GϾA 10 E 3 E60X 310GϾT 11 E 3 P67L 332CϾT 12 E 3 R74Q 353GϾA 13 E 3 R75X 355CϾT 14 E 3 G85E 386GϾA 15 E 3 G91R 403GϾA 16 IVS 3 Splicing defect 405 ϩ 1GϾA 17 IVS 3 Possible splicing defect 405 ϩ 3AϾC 18 IVS 3 Splicing defect 406 - 1GϾA 19 E 4 E92X 406GϾT 20 E 4 E92K 406GϾA 21 E 4 Q98R 425AϾG 22 E 4 Q98P 425AϾC 23 E 4 Frameshift 444delA 24 E 4 Frameshift 457TATϾG 25 E 4 R117C 481CϾT 26 E 4 R117H 482GϾA 27 E 4 R117P 482GϾC 28 E 4 R117L 482GϾT 29 E 4 Y122X 498TϾA 30 E 4 Frameshift 574delA 31 E 4 I148T 575TϾC 32 E 4 Splicing defect 621GϾA 33 IVS 4 Splicing defect 621 ϩ 1GϾT 34 IVS 4 Splicing defect 621 ϩ 3AϾG 35 E 5 Frameshift 624delT 36 E 5 Frameshift 663delT 37 E 5 G178R 664GϾA 38 E 5 Q179K 667CϾA 39 IVS 5 Splicing defect 711 ϩ 1GϾT 40 IVS 5 Splicing defect 711 ϩ 1GϾA 41 IVS 5 Splicing defect 712 - 1GϾT 42 E 6a H199Y 727CϾT 43 E 6a P205S 745CϾT 44 E 6a L206W 749TϾG 45 E 6a Q220X 790CϾT 46 E 6b Frameshift 935delA 47 E 6b Frameshift 936delTA 48 E 6b N287Y 991AϾT 49 IVS 6b Splicing defect 1002 - 3TϾG 50 E 7 ⌬F311 3-bp del between nucleotides 1059 and 1069 51 E 7 Frameshift 1078delT 52 E 7 Frameshift 1119delA 53 E 7 G330X 1120GϾT 54 E 7 R334W 1132CϾT 55 E 7 I336K 1139TϾA 56 E 7 T338I 1145CϾT 57 E 7 Frameshift 1154insTC 58 E 7 Frameshift 1161delC 59 E 7 L346P 1169TϾC 60 E 7 R347H 1172GϾA 61 E 7 R347P 1172GϾC 62 E 7 R347L 1172GϾT 63 E 7 R352Q 1187GϾA 64 E 7 Q359K/T360K 1207CϾA and 1211CϾA 65 E 7 S364P 1222TϾC 66 E 8 Frameshift 1259insA 67 E 8 W401X (TAG) 1334GϾA 68 E 8 W401X (TGA) 1335GϾA 69 IVS 8 Splicing changes 1342 - 6 poly(T) variants 5T/7T/9T 70 IVS 8 Splicing defect 1342 - 2AϾC Table 1. Continued CFTR location Amino acid change Nucleotide change 71 E 9 A455E 1496CϾA 72 E 9 Frameshift 1504delG 73 E 10 G480C 1570GϾT 74 E 10 Q493X 1609CϾT 75 E 10 Frameshift 1609delCA 76 E 10 ⌬I507 3-bp del between nucleotides 1648 and 1653 77 E 10 ⌬F508 3-bp del between nucleotides 1652 and 1655 78 E 10 Frameshift 1677delTA 79 E 10 V520F 1690GϾT 80 E 10 C524X 1704CϾA 81 IVS 10 Possible splicing defect 1717 - 8GϾA 82 IVS 10 Splicing defect 1717 - 1GϾA 83 E 11 G542X 1756GϾT 84 E 11 G551D 1784GϾA 85 E 11 Frameshift 1784delG 86 E 11 S549R (AϾC) 1777AϾC 87 E 11 S549I 1778GϾT 88 E 11 S549N 1778GϾA 89 E 11 S549R (TϾG) 1779TϾG 90 E 11 Q552X 1786CϾT 91 E 11 R553X 1789CϾT 92 E 11 R553G 1789CϾG 93 E 11 R553Q 1790GϾA 94 E 11 L558S 1805TϾC 95 E 11 A559T 1807GϾA 96 E 11 R560T 1811GϾC 97 E 11 R560K 1811GϾA 98 IVS 11 Splicing defect 1811 ϩ 1.6 kb AϾG 99 IVS 11 Splicing defect 1812 - 1GϾA 100 E 12 Y563D 1819TϾG 101 E 12 Y563N 1819TϾA 102 E 12 Frameshift 1833delT 103 E 12 D572N 1846GϾA 104 E 12 P574H 1853CϾA 105 E 12 T582R 1877CϾG 106 E 12 E585X 1885GϾT 107 IVS 12 Splicing defect 1898 ϩ 5GϾT 108 IVS 12 Splicing defect 1898 ϩ 1GϾA 109 IVS 12 Splicing defect 1898 ϩ 1GϾC 110 IVS 12 Splicing defect 1898 ϩ 1GϾT 111 E 13 Frameshift 1924del7 112 E 13 del of 28 amino acids 1949del84 113 E 13 I618T 1985TϾC 114 E 13 Frameshift 2183AAϾG 115 E 13 Frameshift 2043delG 116 E 13 Frameshift 2055del9ϾA 117 E 13 D648V 2075TϾA 118 E 13 Frameshift 2105-2117 del13insAGAA 119 E 13 Frameshift 2108delA 120 E 13 R668C 2134CϾT 121 E 13 Frameshift 2143delT 122 E 13 Frameshift 2176insC 123 E 13 Frameshift 2184delA 124 E 13 Frameshift 2184insA 125 E 13 Q685X 2185CϾT 126 E 13 R709X 2257CϾT 127 E 13 K710X 2260AϾT 128 E 13 Frameshift 2307insA 129 E 13 V754M 2392GϾA 130 E 13 R764X 2422CϾT 131 E 14a W846X 2670GϾA 132 E 14a Frameshift 2734delGinsAT 133 E 14b Frameshift 2766del8 134 IVS 14b Splicing defect 2789 ϩ 5GϾA 135 IVS 14b Splicing defect 2790 - 2AϾG 136 E 15 Q890X 2800CϾT 137 E 15 Frameshift 2869insG 138 E 15 S945L 2966CϾT 139 E 15 Frameshift 2991del32 140 E 16 Splicing defect 3120GϾA interrogation: ACCAACATGTTTTCTTTGATCTTAC 3121-2A3G,T S; 5Ј-ACCAACATGTTTTCTTTGATCTTAC A GTTGTTATTAATTGTGATTGGAGCTATAG-3Ј; CAACAA- TAATTAACACTAACCTCGA 3121-2A3G,T AS. Login to comment
73 Genomic DNA Samples Used for Mutation Evaluation on the APEX Array Mutations validated with native DNA CFTRdel 2,3 (21 kb) 394delTT G85E R75X 574delA Y122X R117C R117H 621 ϩ 1GϾT 621 ϩ 3AϾG 711 ϩ 1GϾT I336K R334W R347P IVS8-5T IVS8-7T IVS8-9T A455E ⌬F508 ⌬I507 1677delTA 1717 - 1GϾA G542X G551D R553X R560T S549N 1898 ϩ 1GϾA 1898 ϩ 1GϾC 2183AAϾG 2043delG R668C 2143delT 2184delA 2184insA 2789 ϩ 5GϾA S945L 3120 ϩ 1GϾA I1005R 3272 - 26AϾG R1066C G1069R Y1092X (CϾA) 3500 - 2AϾT R1158X R1162X 3659delC S1235R 3849 ϩ 10 kb CϾT W1282X primer. Login to comment

[hide] Complete gene scanning by temperature gradient cap... J Mol Diagn. 2005 Feb;7(1):111-20. Chou LS, Gedge F, Lyon E
Complete gene scanning by temperature gradient capillary electrophoresis using the cystic fibrosis transmembrane conductance regulator gene as a model.
J Mol Diagn. 2005 Feb;7(1):111-20., [PMID:15681482]

Abstract [show]
Many inherited diseases involve large genes with many different mutations. Identifying a wide spectrum of mutations requires an efficient gene-scanning method. By differentiating thermodynamic stability and mobility of heteroduplexes from heterozygous samples, temperature gradient capillary electrophoresis (TGCE) was used to scan the entire coding region of the cystic fibrosis transmembrane conductance regulator gene. An initial panel (29 different mutations) showed 100% agreement between TGCE scanning and previously genotyped results for heterozygous samples. Different peak patterns were observed for single base substitutions and base insertions/deletions. Subsequently, 12 deidentified clinical samples genotyped as wild type for 32 mutations were scanned for the entire 27 exons. Results were 100% concordance with the bidirectional sequence analysis. Ten samples had nucleotide variations including a reported base insertion in intron 14b (2789 + 2insA) resulting in a possible mRNA splicing defect, and an unreported missense mutation in exon 20 (3991 G/A) with unknown clinical significance. This methodology does not require labeled primers or probes for detection and separation through a temperature gradient eliminates laborious temperature optimization required for other technologies. TGCE automation and high-throughput capability can be implemented in a clinical environment for mutation scanning with high sensitivity, thus reducing sequencing cost and effort.

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75 Mutation Samples with Known Genotypes Scanned by TGCE* Exon Mutation† Amplicon size (bp) Location of mutation from 5Ј end (bp) Base change Detection‡ 3 G85E 234 124 G to A 1/1 3 394delTT 234 132 del TT 1/1 4 R117H 270 83 G to T 2/2 4 I148T 270 176 T to C 3/3 Intron 4 621 ϩ 1 G/T 270 233 G to T 1/1 5 663delT/663delT 186 75 del T 0/1 Intron 5 711 ϩ 1 G/T 186 124 G to T 1/1 7 R334W 345 208 C to T 1/1 7 R347P 345 248 G to C 1/1 9 A455E 263 155 C to A 2/2 10 I506V 292 168 A to G 1/1 10 ⌬I507 292 171 del ATC 2/2 10 ⌬F508 292 174 del TTT 2/2 10 ⌬F508/⌬F508 292 174 del TTT 0/1 10 F508C 292 175 T to G 1/1 10 V520F 292 210 G to T 1/1 Intron 10 1717-1 G/A 175 50 G to A 1/1 11 G542X 175 90 G to T 2/2 11 G542X/G542X 175 90 G to T 0/1 11 G551D 175 118 G to A 3/3 11 R553X 175 123 C to T 3/3 11 R560T 175 145 G to C 2/2 13 2184delA 834 356 del A 1/1 Intron 14b 2789 ϩ 5G/A 192 102 G to A 1/1 Intron 16 3120 ϩ 1G/A 216 111 G to A 1/1 19 R1162X 322 68 C to T 1/1 19 3659delC 322 111 del C 1/1 20 W1282X 206 154 G to A 1/1 21 N1303K 250 175 C to G 2/2 Total exon/intron Overall accuracy 17 93% *Samples were compared with their respective wild-type control (confirmed by sequencing). Login to comment
118 Another example of reduced resolution is heterozygous A455E in exon 9. Login to comment
119 A shoulder instead of a small peak was observed in heterozygous A455E when compared to the wild-type control (Figure 5, A and B). Login to comment
149 A: Wild-type (exon 9 of the CFTR gene); B: A455E heterozygous (exon 9 of the CFTR gene). Login to comment
156 In addition, we have sequenced exon 9 for all 12 samples because the mutation A455E is difficult to be detected in some systems. Login to comment

[hide] Rapid screening for 31 mutations and polymorphisms... Methods Mol Med. 2005;114:147-71. Dunbar SA, Jacobson JW
Rapid screening for 31 mutations and polymorphisms in the cystic fibrosis transmembrane conductance regulator gene by Lminex xMAP suspension array.
Methods Mol Med. 2005;114:147-71., [PMID:16156102]

Abstract [show]
A suspension array hybridization assay is described for the detection of 31 mutations and polymorphisms in the cystic fibrosis transmembrane conductance regulator (CFTR) gene using Luminex xMAP technology. The Luminex xMAP system allows simultaneous detection of up to 100 different targets in a single multiplexed reaction. Included in the method are the procedures for design of oligonucleotide capture probes and PCR amplification primers, coupling oligonucleotide capture probes to carboxylated microspheres, hybridization of coupled microspheres to oligonucleotide targets, production of targets from DNA samples by multiplexed PCR amplification, and detection of PCR-amplified targets by direct hybridization to probe-coupled microspheres. Mutation screening with the system is rapid, requires relatively few sample manipulations, and provides adequate resolution to reliably genotype the 25 CFTR mutations and 6 CFTR polymorphisms contained in the ACMG/ACOG/NIH-recommended core mutation panel for general population CF carrier screening.

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25 A 635-nm 10-mW red diode laser excites the two fluo- 148 Dunbar and Jacobson xMAP™ 149 Table 1 Recommended Core Mutation Panel for General Population Cystic Fibrosis (CF) Carrier Screening Standard mutation panel ΔF508 ΔI507 G542X G551D W1282X N1303K R553X 621+1G→T R117H 1717-1G→A A455E R560T R1162X G85E R334W R347P 711+1G→T 1898+1G→A 2184delA 1078delT 3849+10kbC→T 2789+5G→A 3659delC 1148T 3120+1G→A Reflex tests I506Va I507Va F508Ca 5T/7T/9Tb a Benign variants. Login to comment
94 Methods The methods described below include: (1) design of oligonucleotide capture probes, (2) design of PCR amplification primers and multiplexed PCR reactions, (3) preparation of the probe-conjugated microsphere sets, (4) verification 150 Dunbar and Jacobson xMAPTM Table 2 Oligonucleotide Capture Probesa Target Microsphere Probe sequence Modificationb Sequence 5' → 3' set Standard mutation panel 1c I507 & F508 5'-AmMC12 AACACCAAAGATGATATTTT 006 2B DI507 5'-AmMC12 ACACCAAAGATATTTTCTT 008 3B DF508 5'-AmMC12 AAACACCAATGATATTTTC 015 4B W1282 5'-AmMC12 CAACAGTGGAGGAAAGCC 012 5B W1282X 5'-AmMC12 CAACAGTGAAGGAAAGCC 020 6 1717-1G 5'-AmMC12 TTGGTAATAGGACATCTCCA 017 7 1717-1GÆA 5'-AmMC12 TTGGTAATAAGACATCTCCA 019 8B G542 5'-AmMC12 TATAGTTCTTGGAGAAGGTGGA 026 9B G542X 5'-AmMC12 TATAGTTCTTTGAGAAGGTGGA 028 10C G551 & R553 5'-AmMC12 AGTGGAGGTCAACGAGCAA 038 11B G551D 5'-AmMC12 GTGGAGATCAACGAGCAA 030 12C R553X 5'-AmMC12 GTGGAGGTCAATGAGCAA 032 13 R560 5'-AmMC12 CTTTAGCAAGGTGAATAACT 035 14 R560T 5'-AmMC12 CTTTAGCAACGTGAATAACT 039 15 R117 5'-AmMC12 AGGAGGAACGCTCTATCGCG 042 16 R117H 5'-AmMC12 AGGAGGAACACTCTATCGCG 025 17B I148 5'-AmMC12 CTTCATCACATTGGAATGCAGA 034 18B I148T 5'-AmMC12 CTTCATCACACTGGAATGCAGA 045 19C 621+1G 5'-AmMC12 TTTATAAGAAGGTAATACTTCCT 046 20E 621+1G→T 5'-AmMC12 ATTTATAAGAAGTTAATACTTCCTT 048 21 N1303 5'-AmMC12 GGGATCCAAGTTTTTTCTAA 051 22 N1303K 5'-AmMC12 GGGATCCAACTTTTTTCTAA 052 23B 1078T 5'-AmMC12 CACCACAAAGAACCCTGA 054 24C 1078delT 5'-AmMC12 ACACCACAAGAACCCTGA 061 25 R334 5'-AmMC12 ATATTTTCCGGAGGATGATT 063 26 R334W 5'-AmMC12 ATATTTTCCAGAGGATGATT 064 27B R347 5'-AmMC12 ACCGCCATGCGCAGAACAA 067 28B R347P 5'-AmMC12 ACCGCCATGGGCAGAACAA 053 29C 711+1G 5'-AmMC12 ATTTGATGAAGTATGTACCTAT 059 30C 711+1G→T 5'-AmMC12 ATTTGATGAATTATGTACCTAT 071 31 G85 5'-AmMC12 TGTTCTATGGAATCTTTTTA 066 32B G85E 5'-AmMC12 ATGTTCTATGAAATCTTTTTA 073 33 3849+10kbC 5'-AmMC12 GTCTTACTCGCCATTTTAAT 077 34 3849+10kbC→T 5'-AmMC12 GTCTTACTCACCATTTTAAT 075 35 A455 5'-AmMC12 CCAGCAACCGCCAACAACTG 011 36D A455E 5'-AmMC12 TCCAGCAACCTCCAACAACTG 036 37 R1162 5'-AmMC12 TAAAGACTCGGCTCACAGAT 060 38 R1162X 5'-AmMC12 TAAAGACTCAGCTCACAGAT 068 39B 3659C 5'-AmMC12 TTGACTTGGTAGGTTTAC 022 40C 3659delC 5'-AmMC12 TTGACTTGTAGGTTTACC 079 41B 2789+5G 5'-AmMC12 TGGAAAGTGAGTATTCCATGTC 074 42D 2789+5G→A 5'-AmMC12 TTGGAAAGTGAATATTCCATGTC 014 43E 2184A 5'-AmMC12 GAAACAAAAAAACAATC 007 44E 2184delA 5'-AmMC12 AGAAACAAAAAACAATC 018 45B 1898+1G 5'-AmMC12 TATTTGAAAGGTATGTTCTTTG 013 (Continued) of microsphere coupling, (5) direct hybridization of biotinylated PCR amplification products to the multiplexed probe-coupled microsphere sets, and (6) results and data analysis. Login to comment
106 Table 3 Reverse Complementary Oligonucleotide Targetsa Target Target sequence Modification Sequence 5' → 3' Standard mutation panel C1b I507 & F508 5'-Biotin AAAATATCATCTTTGGTGTT C2 ΔI507 5'-Biotin AAAGAAAATATCTTTGGTGT C3 ΔF508 5'-Biotin AGAAAATATCATTGGTGTTT C4 W1282 5'-Biotin GGCTTTCCTCCACTGTTGC C5 W1282X 5'-Biotin GGCTTTCCTTCACTGTTGC C6 1717-1G 5'-Biotin TGGAGATGTCCTATTACCAA C7 1717-1G→A 5'-Biotin TGGAGATGTCTTATTACCAA C8 G542 5'-Biotin CCACCTTCTCCAAGAACTAT C9 G542X 5'-Biotin CCACCTTCTCAAAGAACTAT C10 G551 & R553 5'-Biotin CTTGCTCGTTGACCTCCACT C11 G551D 5'-Biotin CTTGCTCGTTGATCTCCACT C12 R553X 5'-Biotin CTTGCTCATTGACCTCCACT C13 R560 5'-Biotin AGTTATTCACCTTGATAAAG C14 R560T 5'-Biotin AGTTATTCACGTTGCTAAAG C15 R117 5'-Biotin CGCGATAGAGCGTTCCTCCT C16 R117H 5'-Biotin CGCGATAGAGTGTTCCTCCT C17 I148 5'-Biotin CTGCATTCCAATGTGATGAA C18 I148T 5'-Biotin CTGCATTCCAGTGTGATGAA C19 621+1G 5'-Biotin GGAAGTATTACCTTCTTATA C20 621+1G→T 5'-Biotin GGAAGTATTAACTTCTTATA C21 N1303 5'-Biotin TTAGAAAAAACTTGGATCCC C22 N1303K 5'-Biotin TTAGAAAAAAGTTGGATCCC C23 1078T 5'-Biotin CTCAGGGTTCTTTGTGGTGT C24 1078delT 5'-Biotin TCTCAGGGTTCTTGTGGTGT C25 R334 5'-Biotin AATCATCCTCCGGAAAATAT C26 R334W 5'-Biotin AATCATCCTCTGGAAAATAT C27 R347 5'-Biotin ATTGTTCTGCGCATGGCGGT C28 R347P 5'-Biotin ATTGTTCTGCCCATGGCGGT C29 711+1G 5'-Biotin TAGGTACATACTTCATCAAA C30 711+1G→T 5'-Biotin TAGGTACATAATTCATCAAA C31 G85 5'-Biotin TAAAAAGATTCCATAGAACA C32 G85E 5'-Biotin TAAAAAGATTTCATAGAACA C33 3849+10kbC 5'-Biotin ATTAAAATGGCGAGTAAGAC C34 3849+10kbC→T 5'-Biotin ATTAAAATGGTGAGTAAGAC C35 A455 5'-Biotin CAGTTGTTGGCGGTTGCTGG C36 A455E 5'-Biotin CAGTTGTTGGAGGTTGCTGG C37 R1162 5'-Biotin ATCTGTGAGCCGAGTCTTTA C38 R1162X 5'-Biotin ATCTGTGAGCTGAGTCTTTA (Continued) Rapid CF Screening by xMAPTM 153 Table 3 (Continued) Target Target sequence Modification Sequence 5' → 3' C39 3659C 5'-Biotin GGTAAACCTACCAAGTCAAC C40 3659delC 5'-Biotin AGGTAAACCTACAAGTCAAC C41 2789+5G 5'-Biotin ACATGGAATACTCACTTTCC C42 2789+5G→A 5'-Biotin ACATGGAATATTCACTTTCC C43 2184A 5'-Biotin AAGATTGTTTTTTTGTTTCT C44 2184delA 5'-Biotin AAGATTGTTTTTTGTTTCTG C45 1898+1G 5'-Biotin AAAGAACATACCTTTCAAAT C46 1898+1G→A 5'-Biotin AAAGAACATATCTTTCAAAT C47 3120+1G 5'-Biotin TTTTTACATACCTGGATGAA C48 3120+1G→A 5'-Biotin TTTTTACATATCTGGATGAA Reflex panel CR2 I506V 5'-Biotin GAAAATGTCATCTTTGGTGT CR3 I507V 5'-Biotin GAAAATATCGTCTTTGGTGT CR4 F508C 5'-Biotin AAAATATCATCTGTGGTGTT CR5 5T 5'-Biotin TCCCTGTTAAAAACACACAC CR6 7T 5'-Biotin CCCTGTTAAAAAAACACACA CR7 9T 5'-Biotin CCTGTTAAAAAAAAACACAC a The position and sequence of the mutation or variation is indicated in bold type. b Target C1 (I507 & F508) is also used in the reflex panel. Login to comment
114 Using a small target DNA (approx 100-300 bp) minimizes the potential for steric hindrance to affect the xMAPTM Table 4 PCR Amplification Primers Size CFTR target Mutation(s) Primer 5' Modification Sequence 5' → 3' (bp) Exon 10 ΔI507, ΔF508, BE10U 5'-Biotin TTCTGTTCTCAGTTTTCCTGG 107 I506V, I507V, E10D None TTGGCATGCTTTGATGACG F508C Exon 20 W1282X E20U None TTGAGACTACTGAACACTGAAGG 126 BE20D 5'-Biotin TTCTGGCTAAGTCCTTTTGC Intron 10 1717-1G→A E11U None TCAGATTGAGCATACTAAAAGTGAC 89 BE11D2 5'-Biotin GAACTATATTGTCTTTCTCTGCAAAC Exon 11 G542X, G551D, E11U2 None AAGTTTGCAGAGAAAGACAATATAG 135 R553X, R560T BE11D 5'-Biotin GAATGACATTTACAGCAAATGC Exon 4 R117H E4U None TTTGTAGGAAGTCACCAAAGC 145 BE4D2 5'-Biotin GAGCAGTGTCCTCACAATAAAGAG Exon 4/intron 4 I148T, E4U2 None CTTCTCTTTATTGTGAGGACACTGC 169 621+1G→T BE4D 5'-Biotin ATGACATTAAAACATGTACGATACAG Exon 21 N1303K BE21U 5'-Biotin TGCTATAGAAAGTATTTATTTTTTCTGG 106 E21D None AGCCTTACCTCATCTGCAAC Exon 7 1078delT, BE7U 5'-Biotin GAACAGAACTGAAACTGACTCG 199 R334W, R347P E7D3 None CAGGGAAATTGCCGAGTG Intron 5 711+1G→T I5U None CAACTTGTTAGTCTCCTTTCC 99 BI5D2 5'-Biotin AGTTGTATAATTTATAACAATAGTGC Exon 3 G85E E3U None CTGGCTTCAAAGAAAAATCC 117 BE3D2 5'-Biotin TGAATGTACAAATGAGATCCTTACC Chromosome 7 3849+10kbC→T BC7U 5'-Biotin GACTTGTCATCTTGATTTCTGG 148 C7D None TTTGGTGCTAGCTGTAATTGC Exon 9 A455E BE9U 5'-Biotin TCACTTCTTGGTACTCCTGTCC 105 E9D None CAAAAGAACTACCTTGCCTGC Exon 19-I R1162X BE19U 5'-Biotin ATTGTGAAATTGTCTGCCATTC 167 E19Da None CAATAATCATAACTTTCGAGAGTTG Exon 19-II 3659delC BE19U2 5'-Biotin TTTAAGTTCATTGACATGCCAAC 91 E19Da None CAATAATCATAACTTTCGAGAGTTG Intron 14B 2789+5G→A I14BU None GTGTCTTGTTCCATTCCAGG 147 BI14BD 5'-Biotin TGGATTACAATACATACAAACATAGTGG Exon 13 2184delA E13U None AGATGCTCCTGTCTCCTGG 126 BE13D 5'-Biotin TGCACAATGGAAAATTTTCGTATAG Intron 12 1898+1G→A I12U None TTAGACTCTCCTTTTGGATACC 110 BI12D 5'-Biotin GTCTTTCTTTTATTTTAGCATGAGC Intron 16 3120+1G→A I16U None ATGACCTTCTGCCTCTTACC 118 BI16D 5'-Biotin ATGAAAACAAAATCACATTTGC Intron 8 5T/7T/9T I8U None TAATGGATCATGGGCCATGTGC 212 BI8D 5'-Biotin ACTGAAGAAGAGGCTGTCATCACC CFTR, cystic fibrosis transmembrane conductance regulator gene. Login to comment
119 Coriell Cell Repositories, NA12960 ΔI507/R347P Patient sample G551D/R347P Coriell Cell Repositories, NA12785 621+1G→T/711+1G→T Coriell Cell Repositories, NA11280 621+1G→T/G85E Coriell Cell Repositories, NA11282 3849+10kbC→T/3849+10kbC→T Coriell Cell Repositories, NA11860 A455E/normal Patient sample 621+1G→T/A455E Coriell Cell Repositories, NA11290 R1162X/normal Coriell Cell Repositories, NA12585 ΔF508/3659delC Coriell Cell Repositories, NA11275 2789+5G→A/2789+5G→A Coriell Cell Repositories, NA11859 2184delA/normal Patient sample 1898+1G→A/normal Patient sample 621+1G→T/3120+1G→A Coriell Cell Repositories, NA07441 3120+1G→A/3120+1G→A Patient sample F508C/normal Coriell Cell Repositories, NA13033 I506V/normal Coriell Cell Repositories, NA13032 R347H/normal Patient sample ΔF508/3120G→A Patient sample S549N/normal Patient sample S549R/normal Patient sample CFTR, cystic fibrosis transmembrane conductance regulator gene. Login to comment

[hide] High heterogeneity of CFTR mutations and unexpecte... J Cyst Fibros. 2004 Dec;3(4):265-72. des Georges M, Guittard C, Altieri JP, Templin C, Sarles J, Sarda P, Claustres M
High heterogeneity of CFTR mutations and unexpected low incidence of cystic fibrosis in the Mediterranean France.
J Cyst Fibros. 2004 Dec;3(4):265-72., [PMID:15698946]

Abstract [show]
In this report, we present updated spectrum and frequency of mutations of the CFTR gene that are responsible for cystic fibrosis (CF) in Languedoc-Roussillon (L-R), the southwestern part of France. A total of 75 different mutations were identified by DGGE in 215 families, accounting for 97.6% of CF genes and generating 88 different mutational genotypes. The frequency of p.F508del was 60.23% in L-R versus 67.18% in the whole country and only five other mutations (p.G542X, p.N1303K, p.R334W, c.1717-1G>A, c.711+1G>T) had a frequency higher than 1%. The mutations were scattered over 20 exons or their border. This sample representing only 5.7% of French CF patients contributed to 24% of CFTR mutations reported in France. This is one of the highest molecular allelic heterogeneity reported so far in CF. We also present the result of a neonatal screening program based on a two-tiered approach "IRT/20 mutations/IRT" analysis on blood spots, implemented in France with the aim to improve survival and quality of life of patients diagnosed before clinical onset. This 18-month pilot project showed an unexpected low incidence of CF (1/8885) in South of France, with only six CF children detected among 43,489 neonates born in L-R, and 13 among 125,339 neonates born in Provence-Alpes-Cote-d'Azur (PACA).

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38 The 20 most common mutations responsible for CF worldwide were investigated by amplification refractory mutation system (ARMS) and migration on agarose gel (Kit Elucigene CF20, including mutations c.1717-1GNA, p.G542X, p.W1282X, p.N1303K, p.F508del, c.3849+10kbCNT, c.621+1GNT, p.R553X, p.G551D, p.R117H, p.R1162X, p.R334W, p.A455E, c.2183AANG, c.3659delC, c.1078delT, p.I507del, p.R347P, p.S1251N, p.E60X). Login to comment
131 The panel of 30 mutations (c.1717-1GNA, p.G542X, p.W1282X, p.N1303K, p.F508del, c.3849+10kbCNT, c.621+1GNT, p.R553X, p.G551D, p.R117H, p.R1162X, p.R334W, p.A455E, c.2183AANG, c.3659delC, c.1078delT, p.I507del, p.R347P, p.S1251N, p.E60X, p.Y1092X, c.394delTT, c.1811+1.6kbANG, c.3272-26ANG, c.2789+5GNA, c.3120+1GNA, c.711+ 1GNT, p.G85E, p.Y122X, p.W846X) should account for 83.32% of the CF alleles in L-R and 84.25% in the whole country. Login to comment

[hide] Microsphere bead arrays and sequence validation of... J Mol Diagn. 2004 Nov;6(4):348-55. Hadd AG, Laosinchai-Wolf W, Novak CR, Badgett MR, Isgur LA, Goldrick M, Walkerpeach CR
Microsphere bead arrays and sequence validation of 5/7/9T genotypes for multiplex screening of cystic fibrosis polymorphisms.
J Mol Diagn. 2004 Nov;6(4):348-55., [PMID:15507674]

Abstract [show]
The development of simple and rapid methods for the detection of the common genetic mutations associated with cystic fibrosis (CF) requires access to positive-control samples including the 5/7/9T variants of intron 8. We used PCR and a simple multiplex bead-array assay to identify 5/7/9T control samples from 29 commercially available DNA samples. Unpurified PCR products were directly hybridized to color-coded beads containing allele-specific capture probes for 5/7/9T detection. The performance of the assay was investigated using reverse-complement oligonucleotides, individual PCR products, and multiplex PCR products for 5/7/9T detection within a complex CFTR screening assay. Samples were genotyped by grouping the relative signal intensities from each capture probe. Of 29 commercially available DNA samples analyzed, 2 5T/7T, 2 5T/9T, 9 7T/9T, 11 7T/7T, and 5 9T/9T genotypes were identified. The genotype within each sample group was confirmed by DNA sequencing. The assay was compatible with the analysis of 10 to 1000 ng of genomic DNA isolated from whole blood and allowed for the separate identification of primary CFTR mutations from reflex variants. The correct identification of positive controls demonstrated the utility of a simple bead-array assay and provided accessible samples for assay optimization and for routine quality control in the clinical laboratory.

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197 Intron 8 Genotype by Coriell Number, Characterized CF Mutation and Allele Fraction for 5/7/9T Intron 8 genotype Coriell sample Characterized mutation Allele fraction by probe 5T 7T 9T 7T/7T NA09947 Normal 0.04 0.93 0.03 NA11277 ⌬I507/normal 0.06 0.90 0.04 NA11761 G551D/R553X 0.06 0.92 0.02 NA11859 2789ϩ5GϾA/2789ϩ5GϾA 0.02 0.96 0.02 NA11860 3849ϩ10kbCϾT/3849ϩ10kbCϾT 0.03 0.94 0.03 NA12444 1717-1GϾT/normal 0.06 0.87 0.07 NA12585 R1162X/normal 0.07 0.86 0.08 NA12785 R347P/G551D 0.04 0.92 0.05 NA12960 R334W/normal 0.06 0.92 0.02 NA12961 V520F/normal 0.06 0.89 0.05 NA13033 F508C/normal 0.03 0.93 0.04 9T/9T NA01531 ⌬F508/⌬F508 0.14 0.04 0.82 NA11281 621ϩ1GϾT/⌬F508 0.14 0.04 0.82 NA11283 A455E/⌬F508 0.13 0.05 0.82 NA11290 A455E/621ϩ1GϾT 0.12 0.01 0.87 NA11496 G542X/G542X 0.14 0.05 0.81 5T/7T NA11723 W1282X/normal 0.53 0.44 0.03 NA13032 I506V/normal 0.58 0.39 0.03 5T/9T NA11279 129GϾC/⌬F508 0.51 0.00 0.49 NA13591 R117H/⌬F508 0.52 0.00 0.48 7T/9T NA07441 3120ϩ1GϾA/621ϩ1GϾA 0.08 0.41 0.51 NA07552 R553X/⌬F508 0.09 0.36 0.55 NA07830 556dA/⌬F508 0.11 0.37 0.52 NA11275 3659dC/⌬F508 0.10 0.37 0.53 NA11278 Q493X/⌬F508 0.09 0.38 0.53 NA11280 711ϩ1GϾT/621ϩ1GϾA 0.09 0.37 0.54 NA11282 G85E/621ϩ1GϾA 0.07 0.39 0.53 NA11284 R560T/⌬F508 0.08 0.39 0.52 NA11472 N1303K/G1349D 0.08 0.39 0.54 Figure 3. Login to comment

[hide] Cystic fibrosis at the Reunion Island (France): sp... J Cyst Fibros. 2004 Aug;3(3):185-8. Dugueperoux I, Bellis G, Lesure JF, Renouil M, Flodrops H, De Braekeleer M
Cystic fibrosis at the Reunion Island (France): spectrum of mutations and genotype-phenotype for the Y122X mutation.
J Cyst Fibros. 2004 Aug;3(3):185-8., [PMID:15463906]

Abstract [show]
BACKGROUND: The Reunion Island is a French administrative department located in the Indian Ocean between the islands of Madagascar and Mauritius. Its population is known to be at a high risk of cystic fibrosis (CF). METHODS: Data concerning all CF patients born at the Reunion Island was extracted from the French CF Registry. Twenty-eight DeltaF508/DeltaF508, 17 Y122X/DeltaF508, and 11 Y122X/Y122X were included in a genotype-phenotype study. RESULTS: The detection rate of the CFTR mutations was 83% among the CF patients born at the Reunion Island. Three CFTR mutations accounted for 75% of the detected CF alleles at the Reunion Island (DeltaF508, Y122X, and 3120 + 1G-->A.). The DeltaF508/DeltaF508, DeltaF508/Y122X, and Y122X/Y122X genotypes accounted for 60.2% of the CF patients. Patients carrying at least one Y122X mutation were pancreatic insufficient, had high sweat chloride values and significantly lower anthropometric measures. The mean anthropometric values in all three groups were lower that in the whole CF population followed in "continental" France. This may reflect the poor compliance and even the refusal of treatment noted by the clinicians. CONCLUSIONS: The distribution of CFTR mutations could be explained by the history of the Reunion Island: admixture of French settlers, African and Asian populations, founder effect and isolation followed by genetic drift. The Y122X allele appears to be associated with a severe phenotype.

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75 G 1 (0.68) DeltaF508/A455E 1 (1.49) 2789 + 5G ! Login to comment
76 A 1 (0.68) DeltaF508/ D993Y 1 (1.49) 993del5 1 (0.68) DeltaF508/ G542X 1 (1.49) A455E 1 (0.68) DeltaF508/2183AA ! Login to comment

[hide] Pancreatitis in hispanic patients with cystic fibr... Clin Gastroenterol Hepatol. 2004 Jun;2(6):504-9. Maisonneuve P, Campbell P 3rd, Durie P, Lowenfels AB
Pancreatitis in hispanic patients with cystic fibrosis carrying the R334W mutation.
Clin Gastroenterol Hepatol. 2004 Jun;2(6):504-9., [PMID:15181620]

Abstract [show]
BACKGROUND & AIMS: Cystic fibrosis (CF) results from abnormal production of sticky mucus, which obstructs many organs. In most cases, the pancreas is severely compromised, but 10%-15% of patients with CF have pancreas sufficiency (PS) and are subject to develop pancreatitis. The aim of this study is to determine which specific genotypes lead to the development of pancreatitis in patients with CF. METHODS: We used prospective data collected by the Cystic Fibrosis Foundation and performed a nested case-control study with all patients who reported at least 1 episode of pancreatitis constituting the cases. We used logistic regression to assess the association between pancreatitis and genotype and the Kaplan-Meier method to estimate the cumulative incidence of pancreatitis for selected genotypes. RESULTS: Three hundred sixty-four of 17,871 genotyped patients with CF (2.0%) reported at least 1 episode of pancreatitis. Only 0.9% of 12,997 patients with genotypes generally associated with pancreas insufficiency reported pancreatitis against 11.9% of 868 patients carrying at least 1 mild CF mutation generally associated with PS. The greatest rate of pancreatitis (19.0%) was observed for patients carrying an R334W mutation: 48% of these 79 patients were Hispanic and 13 patients were living in Puerto Rico. CONCLUSIONS: Of all patients with CF, those carrying an R334W mutation have the greatest risk for developing pancreatitis. This mutation is found mostly in Hispanic patients with CF living in Puerto Rico. There are no current data to determine whether asymptomatic carriers of the R334W mutation are at greater risk for developing pancreatitis or whether this mutation is frequent in Hispanics with idiopathic pancreatitis.

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26 Of Ͼ1000 identified mutations in the CFTR gene, only 25 proven disease-causing mutant alleles (⌬F508, G551D, G542X, R553X, W1282X, R347P, NI303K, R560T, ⌬I507, 1717-1GϾA, A455E, 3120ϩ1GϾA, 621ϩ1GϾT, R117H, 711ϩ1GϾT, R1162X, 3849ϩ10kbCϾT, 2789ϩ5GϾT, R334W, G85E, 1078delT, 1898ϩ1GϾT, 2184delA, 3659delC, and I148T) are recommended by the American College of Medical Genetics for routine diagnostic and carrier testing.16 Most of these are routinely recorded in the CFF registry, but rarer mutations can be recorded if identified by more comprehensive testing. Login to comment
28 Patients were classified according to their genotype: those carrying 2 severe mutations (⌬F508, ⌬I507, G542X, G551D, N1303K, R553X, R560T, R1162X, W1282X, 621ϩ1GϾT, 711ϩ1GϾT, 1717-1GϾA, 2184delA, and 3659delC), which generally are associated with pancreas insufficiency (PI); and those carrying at least 1 mild mutation (3849ϩ10kbCϾT, R117H, 2789ϩ5GϾA, R347P, R334W, and A455E), which are generally associated with PS. Login to comment
42 The greatest frequency of pancreatitis was reported in patients carrying at least 1 R334W mutation (19.0%), followed by patients with a 2789ϩ5GϾA mutation (14.9%), R117H mutation (11.7%), R347P mutation (11.6%), 3849ϩ10kbCϾT mutation (9.0%), A455E mutation (8.3%), or G85E mutation (8.0%; Table 1). Login to comment
64 of patients Patients with pancreatitis At least 1 attack of pancreatitis Ն2 attacks of pancreatitis All genotyped patients with CF 17,871 364 (2.0) - - Pancreas insufficienta 12,997 114 (0.9) 1.0 (reference) 1.0 (reference) Pancreas sufficientb 868 103 (11.9) 9.3 (6.7-12.8) 14.8 (8.2-26.8) 3849ϩ10kbCϾT/anyc 256 23 (9.0) 5.3 (3.1-9.0) 7.1 (2.8-18.3) R117H/anyc 249 29 (11.7) 8.9 (5.5-14.5) 14.1 (6.1-32.7) 2789ϩ5GϾA/anyc 134 20 (14.9) 13.2 (7.3-23.8) 10.4 (3.1-35.5) R347P/anyc 95 11 (11.6) 11.1 (5.3-23.1) 26.6 (9.1-77.4) R334W/anyc,d 79 15 (19.0) 25.8 (13.2-50.5) 43.6 (15.3-124) A455E/anyc 60 5 (8.3) 3.4 (2.6-4.4) 18.3 (5.0-67.9) Genotype incompletely determinede 4006 147 (3.7) 3.4 (2.6-4.4) 6.3 (3.8-10.5) NOTE. Values expressed as number (percent) or odds ratio (95% confidence interval). Login to comment
68 bPatients with pancreas sufficiency (PS) carrying at least 1 PS mutation (3849ϩ10kbCϾT, R117H, 2789ϩ5GϾA, R347P, R334W, A455E). Login to comment

[hide] Therapeutic approaches to repair defects in deltaF... Adv Drug Deliv Rev. 2002 Dec 5;54(11):1395-408. Powell K, Zeitlin PL
Therapeutic approaches to repair defects in deltaF508 CFTR folding and cellular targeting.
Adv Drug Deliv Rev. 2002 Dec 5;54(11):1395-408., [PMID:12458151]

Abstract [show]
The deltaF508 mutation in the cystic fibrosis transmembrane regulator (CFTR) gene is the most common mutation in CF. The mutant CFTR protein is defective with respect to multiple functions including cAMP-regulated chloride conductance, nucleotide transport, and regulatory actions on other ion channels. Since the deltaF508 protein is also temperature-sensitive and unstable during translation and folding in the endoplasmic reticulum (ER), most of the nascent chains are targeted for premature proteolysis from the ER. This paper focuses on the events that occur in the ER during folding and reviews potential targets for therapeutic intervention.

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97 Class V defects (3849 1 10 kB C → T, A455E, by lowering the incubation temperature for cell 2789 1 5G → A) lead to a reduction in the pro-growth, the CFTR may attain a conformation that duction of CFTR, although residual product reaches allows it to escape from degradation in the ER and the surface and is functionally operational. Login to comment
98 Class V defects (3849 1 10 kB C ࢐ T, A455E, by lowering the incubation temperature for cell 2789 1 5G ࢐ A) lead to a reduction in the pro-growth, the CFTR may attain a conformation that duction of CFTR, although residual product reaches allows it to escape from degradation in the ER and the surface and is functionally operational. Login to comment

[hide] Genotype and phenotype correlations in patients wi... Gastroenterology. 2002 Dec;123(6):1857-64. Durno C, Corey M, Zielenski J, Tullis E, Tsui LC, Durie P
Genotype and phenotype correlations in patients with cystic fibrosis and pancreatitis.
Gastroenterology. 2002 Dec;123(6):1857-64., [PMID:12454843]

Abstract [show]
BACKGROUND & AIMS: Pancreatitis is known to occur in some patients with cystic fibrosis (CF), but the prevalence, natural history, and genotypic basis are unclear. We examined a well-defined cohort of patients with CF to answer these questions. METHODS: Patients with CF were identified from a computerized database (1966-1996). Chart audit identified all patients with CF and pancreatitis. RESULTS: Among 1075 patients with CF, 937 (87%) were pancreatic insufficient at diagnosis, 28 (3%) were pancreatic sufficient but developed pancreatic insufficiency after diagnosis, and 110 (10%) have remained pancreatic sufficient. No patients with pancreatic insufficiency developed pancreatitis. Nineteen patients (17.3%) with pancreatic sufficiency experienced one or more attacks of pancreatitis. The mean age at diagnosis of pancreatitis was 22.7 +/- 10.3 years (range, 10-35 years), and pancreatitis was recognized before the diagnosis of CF in 6 patients (32%). The diagnosis of CF in pancreatic-sufficient patients, with and without pancreatitis, was established at a significantly older age than in those with pancreatic insufficiency (P < 0.0001). Genotyped patients with pancreatic insufficiency carried 2 severe mutant alleles. All genotyped patients with pancreatic sufficiency and pancreatitis carried at least one mild mutation. No specific genotype was predictive of pancreatitis. CONCLUSIONS: Patients with CF with pancreatic sufficiency carry at least one mild mutant allele and are at a significant risk of developing pancreatitis. Symptoms of pancreatitis may precede the diagnosis of CF. Pancreatitis is associated with an otherwise mild CF phenotype.

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105 CFTR Genotypes Among CF Patients With PS With and Without Pancreatitis Two mutations (n) ⌬F508/R117H (9) ⌬F508/(5T) (6) ⌬F508/3272-26A 3 G (4) ⌬F508/R347H (2) ⌬F508/P574H (2) ⌬F508/875 ϩ 1G Ͼ C (2) ⌬F508/3849 ϩ 10kb C 3 T (1) ⌬F508/A455E (1) ⌬F508/D614G (1) ⌬F508/G85E (1) ⌬F508/R347P (1) ⌬F508/S1251N (1) ⌬F508/⌬F508a (1) ⌬F508/3120G Ͼ A (1) ⌬F508/G551Da (1) G542X/R117H (1) R560T/L206W (1) R117H/R117H (1) R31L/P67L (1) 1461ins4 (AGAT)/G85E (1) G551D/(5T) (1) R1066C/3849 ϩ 10kb C Ͼ T (1) G551D/3849 ϩ 10kb C Ͼ T (1) R334W/R334W (1) R334W/681delC (1) W1282X/3489 ϩ 10kb C Ͼ T (1) One mutation (n) ⌬F508/- (18) L1077P/- (1) W1282X/- (1) M1137V/- (1) G551D/- (1) R347H/- (1) Q30X1/- (1) G1244E/- (1) R117H/- (1) 621 ϩ 2G621 ϩ 1G 3 T/- (1) NOTE. Login to comment
124 of episodes of pancreatitis Genotype 1 0.3 12 21.7 2 ⌬F508/S1251N 2 0.3 34 30.0 1 ⌬F508/R347H 3 4.4 13 42.5 3 / 4 4.4 21 36.5 1 ⌬F508/ 5 7.3 26 40.8 10 ⌬F508/P67L 6 9.6 29 29.9 (D) 1 ⌬F508/ 7 12.0 18 39.9 1 ⌬F508/R347P 8 12.9 37 40.9 2 G542X/D1152H 9 13.0 30 50.3 1 ⌬F508/3849 ϩ 10Kbc Ͼ T 10 14.7 13 21.5 1 DF508/R117H 11 15.6 34 40.8 1 ⌬F508/2789ϩ5G Ͼ T 12 15.6 10 26.0 10 ⌬F508/R117H 13 16.0 10 22.0 14 ⌬F/508/3849 ϩ 10kbC Ͼ T 14 16.0 18 21.2 (D) 1 R1066C/3849 ϩ 10kbC Ͼ T 15 19.9 15 40.8 5 No DNA 16 23.2 19 23.2 15 ⌬F508/11234V 17 24.1 40 47.6 (D) 1 No DNA 18 26.9 25 43.3 12 No DNA 19 27.4 35 50.3 (D) 2 ⌬F508/A455E NOTE. Login to comment

[hide] Cystic fibrosis and related diseases of the pancre... Best Pract Res Clin Gastroenterol. 2002 Jun;16(3):511-26. Naruse S, Kitagawa M, Ishiguro H, Fujiki K, Hayakawa T
Cystic fibrosis and related diseases of the pancreas.
Best Pract Res Clin Gastroenterol. 2002 Jun;16(3):511-26., [PMID:12079272]

Abstract [show]
The discovery of the gene for cystic fibrosis (CF), the cystic fibrosis transmembrane conductance regulator (CFTR), brought about a new era in the study of this disease. Identification of the molecular target has yielded a flood of data that add to our understanding of the pathogenesis, diagnosis and treatment of CF. The CFTR protein is a cAMP-regulated Cl(-) channel with multiple functions in epithelial cells. In the exocrine pancreas the CFTR plays a key role in the apical Cl(-), HCO(3)(-), and water transport in duct cells. The severe loss of functions, caused by mutations of the CFTR gene, leads to pathological lesions of the pancreas. Over 1200 CFTR mutations and polymorphisms have been identified and their diversity may explain the high level of heterogeneity in the CF phenotype. Mutation analyses of the CFTR gene have revealed a spectrum of CFTR-related diseases that do not fit the classical CF picture but are associated with dysfunction of CFTR, such as chronic pancreatitis.

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62 is observed only when normal CFTR function is less than 1%.13 In general, patients with pancreatic insuciency are homozygous or compound heterozygous for two severe mutations (class I, II or III in Figure 3), such as DF508, DI507, Q493X, G542X, R553X, W1282X, 621 1G 4 T, 1717-1G 4 A, 556delA, 3659delC, I148T, G480C, V520F, G551D, and R560T, whereas the PS phenotype occurs in patients who have one or two mild CFTR mutations, such as R117H, R334W, R347P, A455E, and P574H (class IV or V).5,20 EXOCRINE PANCREAS IN CYSTIC FIBROSIS Pathology of the pancreas in CF There is a spectrum of pancreatic abnormalities in CF irrespective of age.21,22 Pancreatic lesions may be absent in an individual case, but in long-standing CF the pancreas is small, hard and nodular with increased fat and multiple cysts; hence the name `cystic ®brosis of the pancreas'. Login to comment
64 is observed only when normal CFTR function is less than 1%.13 In general, patients with pancreatic insuQciency are homozygous or compound heterozygous for two severe mutations (class I, II or III in Figure 3), such as DF508, DI507, Q493X, G542X, R553X, W1282X, 621 W 1G 4 T, 1717-1G 4 A, 556delA, 3659delC, I148T, G480C, V520F, G551D, and R560T, whereas the PS phenotype occurs in patients who have one or two mild CFTR mutations, such as R117H, R334W, R347P, A455E, and P574H (class IV or V).5,20 EXOCRINE PANCREAS IN CYSTIC FIBROSIS Pathology of the pancreas in CF There is a spectrum of pancreatic abnormalities in CF irrespective of age.21,22 Pancreatic lesions may be absent in an individual case, but in long-standing CF the pancreas is small, hard and nodular with increased fat and multiple cysts; hence the name `cystic &#ae;brosis of the pancreas'. Login to comment

[hide] CFTR mutations in three Latin American countries. Am J Med Genet. 2000 Apr 10;91(4):277-9. Restrepo CM, Pineda L, Rojas-Martinez A, Gutierrez CA, Morales A, Gomez Y, Villalobos MC, Borjas L, Delgado W, Myers A, Barrera-Saldana HA
CFTR mutations in three Latin American countries.
Am J Med Genet. 2000 Apr 10;91(4):277-9., [PMID:10766983]

Abstract [show]
We analyzed 192 cystic fibrosis (CF) alleles in three Latin American countries: Mexico, Colombia, and Venezuela. Mutation screening was performed by polymerase chain reaction (PCR) and a reverse dot blot detection kit that enables determination of 16 of the most common CF mutations worldwide. Mutations were detected in 47.9% of the screened CF alleles. The most prevalent CF allele was DeltaF508 (39. 6%). The remaining 16 non-DeltaF508 detectable mutations represented 8.3% of the CF alleles. Among them, the G542X, N1303K, and 3849+10kb C>T were the most common. Although the frequency of DeltaF508 described here is lower than that reported for Caucasian populations, including in Spain, it is remarkable that mutation prevalences found in this study resemble those observed in Spain. Two of these mutations, G542X and 3849+10kb C>T, that were relevant in this analysis, have a particularly high incidence in Spanish communities. The low frequency of DeltaF508 described here may be explained by the Amerindian, Caucasian, and Black admixture that occurred in Latin America after the discovery of the New World, and also by the probable occurrence of mutations contributed by the original natives, which were undetectable in this analysis.

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34 The isolated DNA from each patient was amplified by polymerase chain reaction (PCR) using a kit for reverse dot blot detection of 16 common CF mutations: ⌬F508, R553X, G542X, G551D, N1303K, W1282X, R117H, R334W, R347P, A455E, ⌬I507, 1717-1 G>A, R560T, 3849+10kb C>T, 621+1 G>T, S549N [Villalobos-Torres et al., 1997]. Login to comment

[hide] Spectrum of CFTR mutations in cystic fibrosis and ... Hum Mutat. 2000;16(2):143-56. Claustres M, Guittard C, Bozon D, Chevalier F, Verlingue C, Ferec C, Girodon E, Cazeneuve C, Bienvenu T, Lalau G, Dumur V, Feldmann D, Bieth E, Blayau M, Clavel C, Creveaux I, Malinge MC, Monnier N, Malzac P, Mittre H, Chomel JC, Bonnefont JP, Iron A, Chery M, Georges MD
Spectrum of CFTR mutations in cystic fibrosis and in congenital absence of the vas deferens in France.
Hum Mutat. 2000;16(2):143-56., [PMID:10923036]

Abstract [show]
We have collated the results of cystic fibrosis (CF) mutation analysis conducted in 19 laboratories in France. We have analyzed 7, 420 CF alleles, demonstrating a total of 310 different mutations including 24 not reported previously, accounting for 93.56% of CF genes. The most common were F508del (67.18%; range 61-80), G542X (2.86%; range 1-6.7%), N1303K (2.10%; range 0.75-4.6%), and 1717-1G>A (1.31%; range 0-2.8%). Only 11 mutations had relative frequencies >0. 4%, 140 mutations were found on a small number of CF alleles (from 29 to two), and 154 were unique. These data show a clear geographical and/or ethnic variation in the distribution of the most common CF mutations. This spectrum of CF mutations, the largest ever reported in one country, has generated 481 different genotypes. We also investigated a cohort of 800 French men with congenital bilateral absence of the vas deferens (CBAVD) and identified a total of 137 different CFTR mutations. Screening for the most common CF defects in addition to assessment for IVS8-5T allowed us to detect two mutations in 47.63% and one in 24.63% of CBAVD patients. In a subset of 327 CBAVD men who were more extensively investigated through the scanning of coding/flanking sequences, 516 of 654 (78. 90%) alleles were identified, with 15.90% and 70.95% of patients carrying one or two mutations, respectively, and only 13.15% without any detectable CFTR abnormality. The distribution of genotypes, classified according to the expected effect of their mutations on CFTR protein, clearly differed between both populations. CF patients had two severe mutations (87.77%) or one severe and one mild/variable mutation (11.33%), whereas CBAVD men had either a severe and a mild/variable (87.89%) or two mild/variable (11.57%) mutations.

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103 b 3905insT, 1811+1.6kbA>G, S945L, S1251N, Y122X, 2711delT, R117H, E60X, 2184insA, E585X, L558S, S1235R, D1152H, K710X, Q493X, A455E, G178R, I148T, 574delA. Login to comment
141 Some mutants are misprocessed (class II) but generate channels that retain significant activity which is sufficient to confer a milder clinical phenotype (for instance, A455E or P574H). Login to comment
152 Twenty-four non F508del mutations were found associated with the 9T allele: 394delTT, L90S, D110H, R117G, 621+1G>T, V232D, A455E, G542X, R851L, T908N, 2789+5G>A, 2896insAG, H939R, 3007delG, I980K, I1027T, R1066H, A1067T, D1154G, 3737delA, R74W+D1270N, N1303I, N1303K, D1377H. Login to comment

[hide] Genotype-phenotype correlations for the paranasal ... Am J Respir Crit Care Med. 1999 May;159(5 Pt 1):1412-6. Jorissen MB, De Boeck K, Cuppens H
Genotype-phenotype correlations for the paranasal sinuses in cystic fibrosis.
Am J Respir Crit Care Med. 1999 May;159(5 Pt 1):1412-6., [PMID:10228103]

Abstract [show]
Genotype-phenotype correlations in cystic fibrosis (CF) have been found for lung and pancreatic function, but not for paranasal sinus disease. Because such correlations may have pathophysiological and clinical implications, the correlation of mutations, in particular DeltaF508, with paranasal sinus disease was investigated in 113 CF patients with known genotype. The clinical importance of paranasal sinus disease was evaluated using three parameters: polyps, overall clinical severity of upper airway problems, and surgery. Polyps were evaluated by nasal endoscopy and graded on a five-point scale. Four severity groups were distinguished based on history, clinical records, and examination: no upper airway problems; more problems than in control subjects; severe, recurrent or chronic problems; and paranasal sinus surgery cases. DeltaF508 homozygosity correlated with clinical severity (p < 0.02) and with the presence of polyps on endoscopy (p < 0.05). The relative risk for paranasal sinus surgery in DeltaF508 homozygous CF patients was 2.33. In conclusion, there are genotype-phenotype correlations for paranasal sinus disease in CF. DeltaF508 homozygosity is a risk factor for paranasal sinus disease in CF.

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16 The mutation ⌬F508, associated with pancreatic insufficiency and diagnosis at younger age, is classified as a "severe" mutation (6), whereas others such as R117H and A455E are considered to be "mild" mutations. Login to comment
17 A455E also correlated with better lung function (7); a correlation between ⌬F508 and lung function was not found (8, 9). Login to comment
93 Three of them had a mild mutation (R117H or A455E) and were clinically classified as class 0 (n ϭ 2) or class 1 (n ϭ 1). Login to comment
94 The fourth patient had undergone sinus surgery and was ⌬F508 negative (G542X/unidentified). Login to comment
120 of Patients in Surgical Group ⌬F508 Genotype Homozygosity 69 61 22 Compound heterozygosity 33 29 5 Negative 11 10 1 Mutations ⌬F508 171 75.7 27 Non-⌬F508 55 24.3 6 R117H (4) C276X (1) 394delT (1) W401X (2,† ) A455E (1) G542X (4,‡ ) G551D (1) R553X (1) G628R(G→C) (1) Y1092X (1) D1152H (1) S1251N (1) W1282X (3) N1303K (8) W1310X (1) 1717-1G→A (3,† ) 1898ϩ1G→C (1) 2183AA-G (3,†† ) 3659delC (2) 3272-26A→G (2,† ) 4218-insT (2) unknown (11,‡ ) * The genotype and mutations are given for the 113 patients with CF. Login to comment
121 of Patients in Surgical Group DF508 Genotype Homozygosity 69 61 22 Compound heterozygosity 33 29 5 Negative 11 10 1 Mutations DF508 171 75.7 27 Non-DF508 55 24.3 6 R117H (4) C276X (1) 394delT (1) W401X (2,ߤ ) A455E (1) G542X (4,ߥ ) G551D (1) R553X (1) G628R(G࢐C) (1) Y1092X (1) D1152H (1) S1251N (1) W1282X (3) N1303K (8) W1310X (1) 1717-1G࢐A (3,ߤ ) 189811G࢐C (1) 2183AA-G (3,ߤߤ ) 3659delC (2) 3272-26A࢐G (2,ߤ ) 4218-insT (2) unknown (11,ߥ ) * The genotype and mutations are given for the 113 patients with CF. Login to comment

[hide] Sunshine, sweating, and main d'accoucheur. Lancet. 1999 May 1;353(9163):1492. Johnson DW, Parnham A, Herzig K, Wittmann J
Sunshine, sweating, and main d'accoucheur.
Lancet. 1999 May 1;353(9163):1492., [PMID:10232317]

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16 Screening for ten of the common cystic fibrosis transmembrane conductance regulator gene (CFTR) mutations (⌬F508, G551D, R553X, G542X, N1303K, A455E, 621+1, Delta I507 and R117H), showed a single delta F508 mutation. Login to comment

[hide] Heterogeneity of reproductive tract abnormalities ... Fertil Steril. 1998 Oct;70(4):724-8. Jarvi K, McCallum S, Zielenski J, Durie P, Tullis E, Wilchanski M, Margolis M, Asch M, Ginzburg B, Martin S, Buckspan MB, Tsui LC
Heterogeneity of reproductive tract abnormalities in men with absence of the vas deferens: role of cystic fibrosis transmembrane conductance regulator gene mutations.
Fertil Steril. 1998 Oct;70(4):724-8., [PMID:9797105]

Abstract [show]
OBJECTIVE: To determine if the types of reproductive tract abnormalities linked to absence of the vas deferens varies with the cystic fibrosis transmembrane conductance regulator (CFTR) genotype. DESIGN: Prospective data gathering. SETTING: University infertility clinic. PATIENT(S): Forty-six infertile men with absence of the scrotal vas deferens and no signs of cystic fibrosis. INTERVENTION(S): All had blood taken for CFTR gene analysis, 33 had scrotal ultrasounds, and 25 had transrectal ultrasounds. MAIN OUTCOME MEASURE(S): The frequency of testicular, seminal vesicle, and ampullae of the vas deferens malformations was compared between subgroups of men with two, one, or no CFTR gene mutations. RESULT(S): None (0 of 21) of the men with at least one CFTR gene mutations had normal ampullae of the vas or seminal vesicles bilaterally. Two (50%) of 4 men with no CFTR gene mutations had normal ampullae of the vas deferens bilaterally, and 50% had normal bilateral seminal vesicles (statistically significantly different). There was no correlation between testicular malformations and CFTR genotype. CONCLUSION(S): This study indicates that the severity of the malformations in the testis is unrelated to the CFTR genotype, whereas the frequency and severity of wolffian duct malformations are related directly to the CFTR genotype.

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60 of men Single mutation 5T /Unknown 13 ⌬F508 /Unknown 8 R117H /Unknown 2 W1282X /Unknown 1 4016insT /Unknown 1 N1303K /Unknown 1 Total 26 Two mutations ⌬F508 /5T 4 ⌬F508 /R117H 2 ⌬F508 /R75Q 1 5T /2183AA3G 1 5T /N1303K 1 5T /G542X 1 R117H /G551A 1 R117H /2184insA 1 A455E /3849ϩ10KbC 1 3T Total 13 No mutations 7 Total no. Login to comment

[hide] Cystic fibrosis: a multiple exocrinopathy caused b... Am J Med. 1998 Jun;104(6):576-90. Schwiebert EM, Benos DJ, Fuller CM
Cystic fibrosis: a multiple exocrinopathy caused by dysfunctions in a multifunctional transport protein.
Am J Med. 1998 Jun;104(6):576-90., [PMID:9674722]

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223 They include another deletion mutation at amino acid position 507 (⌬I507), several missense mutations (F508C, G551D, G551S, A455E, R553Q, P574H, S549N, A559T), and some nonsense mutations (G542X, R553X, Q493X). Login to comment
238 Some of these mutations, however, such as A455E, P574H and G551S have been associated either with less severe pulmonary disease and/or less compromised Cl- channel function. Login to comment
239 A455E causes only a subtle decrease in CFTR Cl- channel activity and fails to prevent regulatory interaction with ORCCs (88). Login to comment

[hide] Mutation frequency of cystic fibrosis transmembran... Fertil Steril. 1998 May;69(5):899-903. Tuerlings JH, Mol B, Kremer JA, Looman M, Meuleman EJ, te Meerman GJ, Buys CH, Merkus HM, Scheffer H
Mutation frequency of cystic fibrosis transmembrane regulator is not increased in oligozoospermic male candidates for intracytoplasmic sperm injection.
Fertil Steril. 1998 May;69(5):899-903., [PMID:9591500]

Abstract [show]
OBJECTIVE: To examine the frequency of anomalies of the vas deferens and the frequency of mutations of the cystic fibrosis transmembrane regulator (CFTR) gene in male candidates for intracytoplasmic sperm injection (ICSI) who had severe oligoasthenoteratozoospermia. DESIGN: The clinical data for male candidates for ICSI were studied. The three most frequent cystic fibrosis (CF)-causing CFTR mutations in the Dutch population (deltaF508, A455E, and G542X) and the three most frequent CFTR mutations potentially causing congenital bilateral absence of the vas deferens (CBAVD) in the Dutch population (deltaF508, R117H, and IVS8-5T) were analyzed. Delta I507 is also detected by the deltaF508 test. Samples of DNA from patients identified as CFTR mutation carriers were subjected to denaturing gradient gel electrophoresis analysis with use of a two-dimensional electrophoretic technique. SETTING: University-based center for reproductive medicine and clinical genetics. PATIENT(S): Male candidates for ICSI who had oligoasthenoteratozoospermia and no history of operative sterilization and refertilization. Males with a chromosomal aberration or a Y-chromosome microdeletion were excluded. INTERVENTION(S): Semen and blood samples were collected from the patients at their first visit to the clinic. MAIN OUTCOME MEASURE(S): Frequency of anomalies of the vas deferens and frequency of mutations of the CFTR gene in male candidates for ICSI who had oligoasthenoteratozoospermia. RESULT(S): None of the patients had abnormalities of the vas deferens at physical examination. In 4 of the 150 chromosomes (75 patients), a CFTR mutation was found, yielding a CFTR mutation frequency of 2.7% (95% confidence interval, 1.0-6.7%). None of the patients had two CFTR mutations. CONCLUSION(S): The frequency of congenital abnormalities of the vas deferens in patients with oligoasthenoteratozoospermia is low. The frequencies of the CFTR mutations identified in this cohort did not differ significantly from the frequencies found in the normal Dutch population.

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2 The three most frequent cystic fibrosis (CF)-causing CFTR mutations in the Dutch population (⌬F508, A455E, and G542X) and the three most frequent CFTR mutations potentially causing congenital bilateral absence of the vas deferens (CBAVD) in the Dutch population (⌬F508, R117H, and IVS8-5T) were analyzed. Login to comment
65 The three most frequent CFTR mutations causing CF in the Dutch population (⌬F508, A455E, and G542X) and the three most frequent CFTR mutations potentially causing congenital bilateral absence of the vas deferens in the Dutch population (⌬F508, R117H, and IVS8-5T) were analyzed. Login to comment
68 Detection of R117H, A455E, and G542X mutations was performed with the use of allele-specific amplification tests, as described by Ferrie et al. (12) for G542X and R117H. Login to comment
69 For the A455E mutation, the following primers were designed (mismatch in lower case): AEC: 5Ј-GACACTACACCCATACATTCTCCTAATG-3Ј, AEM: 5Ј-TCAAGATAGAAAGAGGACAGTTGTTGtA-3Ј, and AEN: 5Ј-TCAAGATAGAAAGAGGACAGTTGTTG- GC-3Ј. Login to comment
92 For the A455E, G542X, and ⌬I507 mutations, the frequency in the normal population was based on the 3.3% carrier frequency and the locally derived relative frequencies of mutations in CF patients (H.S., unpublished data). Login to comment
132 Mutation General population* (95% CI) Patients with OAT† (95% CI) Patients with CBAVD‡ Patients with CF§ ⌬F508 0.013 (0.011-0.015) 0.013 (0.0037-0.047) 0.169 0.777 R117H 0.009 (0.0027-0.030) 0.006 (0.0012-0.037) 0.305 Ͻ0.001 IVS8-5T 0.037 (0.019-0.073) 0.006 (0.0012-0.037) 0.055 ND A455E Ͻ0.001 (ND) 0 (ND) Ͻ0.001 0.026 G542X Ͻ0.001 (ND) 0 (ND) Ͻ0.001 0.015 ⌬I507 Ͻ0.001 (ND) 0 (ND) Ͻ0.001 Ͻ0.001 Total 0.005 (ND)࿣ 0.027 (0.010-0.067) 0.529 0.818 Note: OAT ϭ oligoasthenoteratozoospermia; CBAVD ϭ congenital bilateral absence of the vas deferens; ND ϭ not done. Login to comment
133 * Locally derived frequencies for ⌬F508, R117H, and IVS8-5T (n ϭ 21,544 chromosomes, n ϭ 232 chromosomes, and n ϭ 212 chromosomes, respectively); and theoretical estimates for A455E, G542X, and ⌬I507 based on a 3.3% carrier frequency and regionally derived mutation frequencies (H.S., unpublished data). Login to comment
136 § H.S., unpublished data (n ϭ 726 for ⌬F508, A455E, and G542X; n ϭ 272 for R117H; IVS8-5T not determined). Login to comment

[hide] A mutation in the cystic fibrosis transmembrane co... Hum Mol Genet. 1998 Apr;7(4):729-35. Mickle JE, Macek M Jr, Fulmer-Smentek SB, Egan MM, Schwiebert E, Guggino W, Moss R, Cutting GR
A mutation in the cystic fibrosis transmembrane conductance regulator gene associated with elevated sweat chloride concentrations in the absence of cystic fibrosis.
Hum Mol Genet. 1998 Apr;7(4):729-35., [PMID:9499426]

Abstract [show]
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) have been shown to cause cystic fibrosis (CF) and male infertility due to congenital bilateral absence of the vas deferens. We report the identification of a 6.8 kb deletion (del14a) and a nonsense mutation (S1455X) in the CFTR genes of a mother and her youngest daughter with isolated elevated sweat chloride concentrations. Detailed clinical evaluation of both individuals found no evidence of pulmonary or pancreatic disease characteristic of CF. A second child in this family with classic CF was homozygous for the del14a mutation, indicating that this mutation caused severe CFTR dysfunction. CFTR mRNA transcripts bearing the S1455X mutation were stable in vivo , implying that this allele encoded a truncated version of CFTR missing the last 26 amino acids. Loss of this region did not affect processing of transiently expressed S1455X-CFTR compared with wild-type CFTR. When expressed in CF airway cells, this mutant generated cAMP-activated whole-cell chloride currents similar to wild-type CFTR. Preservation of chloride channel function of S1455X-CFTR was consistent with normal lung and pancreatic function in the mother and her daughter. These data indicate that mutations in CFTR can be associated with elevated sweat chloride concentrations in the absence of the CF phenotype, and suggest a previously unrecognized functional role in the sweat gland for the C-terminus of CFTR.

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151 Mutation analysis Total genomic DNA was assayed for 16 common CFTR mutations (R117H, 621+1G→T, R334W, R349P, A455E, 1717-1G→A, ∆I507, ∆F508, G542X, S549N, G551D, R553X, R560T, 3849+10 kb C→T, W1282X, N1303K) by reverse dot-blot hybridization (46). Login to comment
152 Mutation analysis Total genomic DNA was assayed for 16 common CFTR mutations (R117H, 621+1G࢐T, R334W, R349P, A455E, 1717-1G࢐A, ࢞I507, ࢞F508, G542X, S549N, G551D, R553X, R560T, 3849+10 kb C࢐T, W1282X, N1303K) by reverse dot-blot hybridization (46). Login to comment

[hide] Is meconium ileus genetically determined or associ... J Med Genet. 1998 Mar;35(3):262-3. De Braekeleer M, Allard C, Leblanc JP, Aubin G, Simard F
Is meconium ileus genetically determined or associated with a more severe evolution of cystic fibrosis?
J Med Genet. 1998 Mar;35(3):262-3., [PMID:9541118]

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16 Although the A455E mutation is Table 1 Distribution of meconium ileus among CFTR genotypes in Saguenay Lac-Saint-Jean No of CF Proportion No of CFpatients Proportion Proportion ofMI Genotypes patients (%) with meconium ileus (%) among genotypes AF508/AF508 52 39.4 5 26.3 9.6 AF508/621+G-*T 34 25.8 9 47.4 26.5 AF508/A455E 14 10.6 0 0.0 0.0 621+1G-*T/A455E 8 6.1 0 0.0 0.0 621+1G-*T/G85E 2 1.5 1 5.3 50.0 621+1G-*T/Y1092X 1 0.8 0 0.0 0.0 AF508/Y1092X 4 3.0 1 5.3 25.0 A455E/R117C 1 0.8 0 0.0 0.0 AF508/I148T 2 1.5 0 0.0 0.0 621+1G-*T/ 4 3.0 0 0.0 0.0 711 +1G-*T 621+1G-4T/S489X 1 0.8 0 0.0 0.0 AF508/Q890X 1 0.8 1 5.3 100.0 621+1G->T/ 6 4.5 2 10.5 33.3 621+1G-sT AF508/unknown 1 0.8 1 5.3 100.0 Unknown/unknown 1 0.8 0 0.0 0.0 Table 2 Main clinicalfindings in patients with meconium ileus With MI Without MI p value No of patients 18 18 Sex (M/IF) 6/12 6/12 No of patients alive 16 17 Mean age (SD) 16.75 (9.7) 16.70 (7.9) p=0.99 Mean birth weight (SD) 3.24 (0.40) 3.02 (0.47) p=O.18 Mean birth height (SD) 50.0 (2.27) 50.0 (2.58) p=0.86 Currentweightcentile (SD) 26.7 (24.5) 14.1 (18.0) p=0.06 Current height centile (SD) 29.9 (25.1) 20.6 (25.6) p=0.33 Sweat chloride concentration (mEq/l) 105.9 (6.5) 101.1 (9.8) p=O.12 Mean FVC (SD) 89.7 (24.4) 93.0 (17.0) p=0.75 Mean FEV (SD) 73.1 (23.9) 75.4 (18.7) p=0.81 Mean Shwachman score (SD) 82.8 (11.8) 79.2 (12.6) p=0.36 Colonisation with Pseudomonas aeruginosa 13 14 p=0.70 Staphyloccoccus aureus 16 17 p=0.55 Haemophilus influenzae 13 14 p=0.70 Pseudomonas maltophilia 4 6 p=0.46 Pseudomonas cepacia 0 1 Pancreatic insufficiency 18 18 DIOS 7 1 p=0.016 Rectal prolapse 1 2 p=0.55 Recurrent abdominal pain 6 1 p=0.035 Diabetes mellitus 5 0 p=0.016 Liver complications 3* 0 p=0.07 Nasal polyposis 6 6 p=1.00 DIOS=distal intestinal obstruction syndrome. Login to comment
18 considered to be a "mild" mutation, 13 ofthe 22 patients from SLSJ carrying a AF508/ A455E or a 621+1G-4T/A455E genotype had PI.5 However, none ofthem had MI. Login to comment
51 5 De Braekeleer M, Allard C, Leblanc JP, Simard F, Aubin G. Genotype-phenotype correlation in cystic fibrosis patients compound heterozygous for the A455E mutation. Login to comment
52 5 De Braekeleer M, Allard C, Leblanc JP, Simard F, Aubin G. Genotype-phenotype correlation in cystic fibrosis patients compound heterozygous for the A455E mutation. Login to comment

[hide] A pilot clinical trial of oral sodium 4-phenylbuty... Am J Respir Crit Care Med. 1998 Feb;157(2):484-90. Rubenstein RC, Zeitlin PL
A pilot clinical trial of oral sodium 4-phenylbutyrate (Buphenyl) in deltaF508-homozygous cystic fibrosis patients: partial restoration of nasal epithelial CFTR function.
Am J Respir Crit Care Med. 1998 Feb;157(2):484-90., [PMID:9476862]

Abstract [show]
Sodium 4-phenylbutyrate (Buphenyl, 4PBA) is a new FDA approved drug for management of urea cycle disorders. We have previously presented data suggesting that 4PBA, at clinically achievable concentrations, induces CFTR channel function on the plasma membrane of deltaF508-expressing cystic fibrosis (CF) airway epithelial cells in vitro (Rubenstein, R. C., and P. L. Zeitlin, 1997. J. Clin. Invest. 100:2457-2463). We hypothesized that 4PBA would induce epithelial CFTR function in vivo in individuals homozygous for deltaF508-CFTR. A randomized, double-blind, placebo-controlled trial in 18 deltaF508-homozygous patients with CF was performed with the maximum approved adult dose of 4PBA, 19 grams p.o. divided t.i.d., given for 1 wk. Nasal potential difference (NPD) response patterns and sweat chloride concentrations were determined before and after study drug treatment, and 4PBA and metabolites were assayed in plasma and urine at the end of study drug treatment. Subjects in the 4PBA group demonstrated small, but statistically significant improvements of the NPD response to perfusion of an isoproterenol/amiloride/chloride-free solution; this measure reflects epithelial CFTR function and is highly discriminatory between patients with and without CF. Subjects who had received 4PBA did not demonstrate significantly reduced sweat chloride concentrations or alterations in the amiloride-sensitive NPD. Side effects due to drug therapy were minimal and comparable in the two groups. These data are consistent with 4PBA therapy inducing CFTR function in the nasal epithelia of deltaF508-homozygous CF patients.

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181 Measurement of the NPD in five CF patients with another partially functional CFTR mutation, A455E (substitution of glutamate for alanine at position 455) have recently been published (26). Login to comment
184 It is possible, even though R117H and A455E are both partially functional CFTR mutations, that their interactions with other (as yet undetermined) cellular constituents might differ, and thereby alter NPD responses. Login to comment

[hide] Correlation of sweat chloride concentration with g... Clin Biochem. 1998 Feb;31(1):33-6. De Braekeleer M, Allard C, Leblanc JP, Aubin G, Simard F
Correlation of sweat chloride concentration with genotypes in cystic fibrosis patients in Saguenay Lac-Saint-Jean, Quebec, Canada.
Clin Biochem. 1998 Feb;31(1):33-6., [PMID:9559222]

Abstract [show]
OBJECTIVES: Saguenay Lac-Saint-Jean, a geographically isolated region of northeastern Quebec has a high incidence of cystic fibrosis (CF) and three mutations only account for 94% of the CF chromosomes. The objective of the present study was to determine whether different mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene had different effects upon the sweat chloride concentration. DESIGN AND METHODS: The sweat chloride concentration of 114 patients was measured by quantitative pilocarpine iontophoresis. RESULTS: CF patients carrying the A455E mutation, usually associated with pancreatic sufficiency, had lower sweat chloride concentrations than those carrying mutations associated with pancreatic insufficiency (delta F508 and 621 + 1G-->T). CONCLUSIONS: Our results confirm that mutations resulting in a reduction of the chloride current at the apical membrane of epithelial cells induce lower sweat chloride values. However, there are differences in the chloride current between genotypes, even if they are composed of mutations apparently having the same functional effect.

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3 Results: CF patients carrying the A455E mutation, usually associated with pancreatic sufficiency, had lower sweat chloride concentrations than those carrying mutations associated with pancreatic insufficiency (⌬F508 and 621ϩ1G3T). Login to comment
25 Three CFTR mutations account for 93.7% of the CF chromosomes; these are the ⌬F508 (63.4%), 621ϩ1G3T (22.3%), and A455E (8%) mutations. Login to comment
28 All the 114 CF patients in the present study had pancreatic insufficiency but 7 with a A455E/⌬F508 genotype, 2 with a A455E/621ϩ1G3T genotype and 1 with a R177C/A455E genotype who were pancreatic sufficient. Login to comment
38 Patients with the A455E/⌬F508 or the 621ϩ1G3T/ A455E genotype had significantly lower chloride values than those homozygous for the ⌬F508 mutation (p Ͻ 0.05). Login to comment
40 A significant difference was also found between CF patients carrying the A455E mutation on one chromosome and the ⌬F508 or 621ϩ1G3T mutation on the other chromosome (p Ͻ 0.05). Login to comment
41 There were no significant differences in sweat chloride values between patients homozygous for the ⌬F508 mutation and those having a ⌬F508/ 621ϩ1G3T genotype or being hemizygous for the Y1092X or 711ϩ1G3T mutation (p Ͼ 0.05). Login to comment
44 It was the result of significant differences between the A455E group and the other two groups, ⌬F508 and 621ϩ1G3T (p Ͻ 0.05). Login to comment
45 Patients were classified as hemizygous for the ⌬F508 mutation if the other chromosome did not carry the 621ϩ1G3T, nor the A455E mutation. Login to comment
46 Patients carrying the A455E mutation on one chromosome were included in the A455E mutation category, independently of the second mutation. Login to comment
48 Pancreatic insufficiency (PI) is obtained TABLE 1 Sweat Chloride Concentrations by Genotype or Mutation Among CF Patients in SLSJ Genotype No. of Patients Mean Chloride Concentration (mEq/L) (SD) Minimum Value (mEq/L) Maximum Value (mEq/L) ⌬F508/⌬F508 47 102.77 (8.43) 77 119 621ϩ1G3T/⌬F508 28 103.5 (7.4) 87 120 621ϩ1G3T/A455E 6 94.17 (10.87) 74 106 A455E/⌬F508 12 77.08 (18.48) 54 107 Y1092X/⌬F508 or 621ϩ1G3T 5 100.6 (11.67) 87 117 621ϩ1G3T/621ϩ1G3T 5 112.4 (2.97) 108 116 621ϩ1G3T/711ϩ1G3T 4 106.5 (4.12) 102 110 ⌬F508/other 3 102.33 (11.5) 91 114 Other/other 2 71 62 80 621-other 2 89.5 84 95 Mutation No. of Patients Mean Chloride Concentration (mEq/L) (SD) Minimum Value (mEq/L) Maximum Value (mEq/L) ⌬F508 54 102.28 (8.56) 77 119 621ϩ1G3T 40 104.55 (8.14) 84 120 A455E 19 81.68 (18.14) 54 107 when a CF patient has two 'severe` alleles with respect to the exocrine pancreatic function (⌬F508 being one of them). Login to comment
51 However, the follow-up of CF patients with one mild allele (A455E) has shown that some PS patients may develop pancreatic insufficiency at a later stage of the disease (14). Login to comment
58 Class IV mutations result in a reduction in the amount of chloride current (e.g., R117H, R347P, S1251N mutations) while class V mutations result in a reduction in the amount of a normally functioning CFTR protein (e.g., A455E, 3849ϩ10kbC3T mutations). Login to comment
65 It was the case for ⌬F508/⌬F508 versus 621ϩ1G3T/621ϩ1G3T or A455E/⌬F508 versus A455E/621ϩ1G3T. Login to comment
69 Simone Aubin, Claudette La- rochelle and Suzanne Mignault from the Clinique de TABLE 2 Distribution of the Mean Sweat Chloride Concentration by Genotype Genotype No. of CF Patients Mean Chloride Concentration (mmol/L) (SD) Pancreatic Status References G542X/⌬F508 128 109 (23) Pl 18 R553X/⌬F508 46 105 (18) Pl 18 N1303K/⌬F508 56 104 (24) Pl 18 W1282X/⌬F508 13 110 (18) Pl 18 1717-1G3A/⌬F508 26 107 (36) Pl 18 621ϩ1G3T/⌬F508 22 100 (20) Pl 18 R117H/⌬F508 20 82 (19) PS 18 ⌬F508/⌬F508 328 106 (22) Pl 18 3849ϩ10kb C3T/⌬F508 6 61 (11) PS 19 3849ϩ10kb C3T/⌬F508 9 41 (12) PS (6) 20 R347P/⌬F508 5 100 (26) Pl 21 R334W/⌬F508 10 108 (19) Pl (6) 22 1811ϩ1.6kb A3C/⌬F508a 17 98 (12) Pl 23 3905insT/⌬F508 7 124 Pl 24 W1282X/W1282X 16 113 (12) Pl 25 W1282X/⌬F508 22 109 (11) Pl 25 G551D/⌬F508 58 101 (16) Pl 26 R1162X/R1162X 9 99 (13) Pl 27 1949del84/⌬F508 4 105 (20) Pl 28 ⌬F508/⌬F508 47 103 (8) Pl This study 621ϩ1G3T/⌬F508 28 103 (7) Pl This study 621ϩ1G3T/A455E 6 94 (11) Pl/PS This study A455E/⌬F508 12 77 (18) Pl/PS This study a Or other 'severe` mutations. Login to comment
39 Patients with the A455E/DF508 or the 62111G3T/ A455E genotype had significantly lower chloride values than those homozygous for the DF508 mutation (p , 0.05). Login to comment
47 Patients were classified as hemizygous for the DF508 mutation if the other chromosome did not carry the 62111G3T, nor the A455E mutation. Login to comment
50 Pancreatic insufficiency (PI) is obtained TABLE 1 Sweat Chloride Concentrations by Genotype or Mutation Among CF Patients in SLSJ Genotype No. of Patients Mean Chloride Concentration (mEq/L) (SD) Minimum Value (mEq/L) Maximum Value (mEq/L) DF508/DF508 47 102.77 (8.43) 77 119 62111G3T/DF508 28 103.5 (7.4) 87 120 62111G3T/A455E 6 94.17 (10.87) 74 106 A455E/DF508 12 77.08 (18.48) 54 107 Y1092X/DF508 or 62111G3T 5 100.6 (11.67) 87 117 62111G3T/62111G3T 5 112.4 (2.97) 108 116 62111G3T/71111G3T 4 106.5 (4.12) 102 110 DF508/other 3 102.33 (11.5) 91 114 Other/other 2 71 62 80 621-other 2 89.5 84 95 Mutation No. of Patients Mean Chloride Concentration (mEq/L) (SD) Minimum Value (mEq/L) Maximum Value (mEq/L) DF508 54 102.28 (8.56) 77 119 62111G3T 40 104.55 (8.14) 84 120 A455E 19 81.68 (18.14) 54 107 when a CF patient has two 'severe` alleles with respect to the exocrine pancreatic function (DF508 being one of them). Login to comment
53 However, the follow-up of CF patients with one mild allele (A455E) has shown that some PS patients may develop pancreatic insufficiency at a later stage of the disease (14). Login to comment
60 Class IV mutations result in a reduction in the amount of chloride current (e.g., R117H, R347P, S1251N mutations) while class V mutations result in a reduction in the amount of a normally functioning CFTR protein (e.g., A455E, 3849110kbC3T mutations). Login to comment
67 It was the case for DF508/DF508 versus 62111G3T/62111G3T or A455E/DF508 versus A455E/62111G3T. Login to comment
71 Simone Aubin, Claudette Larochelle and Suzanne Mignault from the Clinique de TABLE 2 Distribution of the Mean Sweat Chloride Concentration by Genotype Genotype No. of CF Patients Mean Chloride Concentration (mmol/L) (SD) Pancreatic Status References G542X/DF508 128 109 (23) Pl 18 R553X/DF508 46 105 (18) Pl 18 N1303K/DF508 56 104 (24) Pl 18 W1282X/DF508 13 110 (18) Pl 18 1717-1G3A/DF508 26 107 (36) Pl 18 62111G3T/DF508 22 100 (20) Pl 18 R117H/DF508 20 82 (19) PS 18 DF508/DF508 328 106 (22) Pl 18 3849110kb C3T/DF508 6 61 (11) PS 19 3849110kb C3T/DF508 9 41 (12) PS (6) 20 R347P/DF508 5 100 (26) Pl 21 R334W/DF508 10 108 (19) Pl (6) 22 181111.6kb A3C/DF508a 17 98 (12) Pl 23 3905insT/DF508 7 124 Pl 24 W1282X/W1282X 16 113 (12) Pl 25 W1282X/DF508 22 109 (11) Pl 25 G551D/DF508 58 101 (16) Pl 26 R1162X/R1162X 9 99 (13) Pl 27 1949del84/DF508 4 105 (20) Pl 28 DF508/DF508 47 103 (8) Pl This study 62111G3T/DF508 28 103 (7) Pl This study 62111G3T/A455E 6 94 (11) Pl/PS This study A455E/DF508 12 77 (18) Pl/PS This study a Or other 'severe` mutations. Login to comment

[hide] Transmembrane domain of cystic fibrosis transmembr... Biochemistry. 1998 Jan 20;37(3):844-53. Wigley WC, Vijayakumar S, Jones JD, Slaughter C, Thomas PJ
Transmembrane domain of cystic fibrosis transmembrane conductance regulator: design, characterization, and secondary structure of synthetic peptides m1-m6.
Biochemistry. 1998 Jan 20;37(3):844-53., [PMID:9454574]

Abstract [show]
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) give rise to cystic fibrosis (CF), the most common genetic disease in the Caucasian population. CFTR is organized into five putative domains, including two that are predicted to be transmembrane and consist of six membrane-spanning segments each. CFTR mediates regulated anion transport across the apical membrane of epithelial cells. The pore through which CFTR transports its solutes is thought to be formed by some combination of the amino-terminal membrane-spanning segments. Although these sequences are predicted to be alpha-helical in secondary structure, to date, no direct structural evidence has been presented testing this hypothesis. Here, we present the biophysical characterization of six peptides (m1-m6) representing the predicted amino-terminal membrane-spanning domain of CFTR. The peptides can be incorporated into liposomes and are soluble in SDS micelles and trifluoroethanol (TFE). FTIR and CD spectroscopy indicate all six peptides adopt a stable, predominantly alpha-helical secondary structure in these environments. In contrast, peptide m6 undergoes a shift from alpha-helix to beta-sheet when dissolved in 20% methanol. Additionally, the peptides show an increase in beta-sheet in TFE, a known inducer of alpha-helices, relative to that seen in the nativelike environments. These results have implications for the folding of this complex membrane protein and suggest that the possible functional role of m6 is manifested through a shift in secondary structure.

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261 The critical importance of this intramembrane residue to CFTR structure is highlighted by the CF-causing mutation of proline 205 to serine (54), which prevents proper folding and processing of CFTR (52) and causes a form of cystic fibrosis similar to other misprocessing mutants such as A455E and P574H (55). Login to comment

[hide] Complete identification of cystic fibrosis transme... Clin Genet. 1998 Jan;53(1):44-6. De Braekeleer M, Mari C, Verlingue C, Allard C, Leblanc JP, Simard F, Aubin G, Ferec C
Complete identification of cystic fibrosis transmembrane conductance regulator mutations in the CF population of Saguenay Lac-Saint-Jean (Quebec, Canada).
Clin Genet. 1998 Jan;53(1):44-6., [PMID:9550360]

Abstract [show]
Over the past few years, we have conducted a systematic study of 230 cystic fibrosis (CF) chromosomes in the Saguenay Lac-Saint-Jean (SLSJ) population which has a high CF incidence (1/936 live births). We identified 11 mutations accounting for 100% of the CF chromosomes found in patients born in SLSJ. Our results indicate that denaturing gradient gel electrophoresis (DGGE) is a powerful method of identifying CF mutations. They have also considerable implications for genetic counselling and molecular characterization of doubtful patients. They make carrier screening technically feasible in this population.

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18 CFTR mutations in Saguenay LacSaint-Jean We previously reported, based on 91 families, that three mutations (AF508,621 +1G+T, and A455E) accounted for 90% of the CF chromosomes while eight mutations represented 93% of the mutations (6, 7). Login to comment
31 There were 11 patients with a AF508/AF508 genotype, two with AF508/621 +l G + T and one with AF508/A455E and N1303K/I148T genotype each. Login to comment
33 Distributon of CFTR mutations in CF patients born in SLSJ Mutations No. CF chromosomes Proportion(%) AF508 120 621tlG-T 51 A455E 17 Y1092X 3 1148T 2 711+1G+T 2 G85E 1 Q890X 1 s489x 1 R117C 1 R1158X 1 60 25.5 8.5 1.5 1 1 0.5 0.5 0.5 0.5 0.5 Table 1 gives the distribution of the mutations found on the C F chromosomes from patients born in the SLSJ region. Login to comment
34 Ninety four percent of the CF chromosomes were accounted for by only three mutations: AF508, 621 +1G+T and A455E. Login to comment
43 Distributionof CFtR genotypes in CF patients born in SLSJ Genotypes No. CF patients AFS08/AF508 AF5@/621+lG-T AF508/A455E 621t 1G+T/A455E 621t 1G+T/621 t 1G-T AF508,N109W AF508/1148T 621t1G+T/711 t1G+T 621t 1G+T/G85E 621t1G+T/YlO92X A455E/R117C 621+1G+TjS489X AF508/Q890X AF508/R1158X 37 30 6 5 2 2 2 1 1 1 1 1 1 45 De Braekeleer et al. identify 100% of the CFTR mutations in the CF population born in SLSJ. Login to comment

[hide] A functional CFTR-NBF1 is required for ROMK2-CFTR ... Am J Physiol. 1997 Nov;273(5 Pt 2):F843-8. McNicholas CM, Nason MW Jr, Guggino WB, Schwiebert EM, Hebert SC, Giebisch G, Egan ME
A functional CFTR-NBF1 is required for ROMK2-CFTR interaction.
Am J Physiol. 1997 Nov;273(5 Pt 2):F843-8., [PMID:9374850]

Abstract [show]
In a previous study on inside-out patches of Xenopus oocytes, we demonstrated that the cystic fibrosis transmembrane conductance regulator (CFTR) enhances the glibenclamide sensitivity of a coexpressed inwardly rectifying K+ channel, ROMK2 (C. M. McNicholas, W. B. Guggino, E. M. Schwiebert, S. C. Hebert, G. Giebisch, and M. E. Egan. Proc. Natl. Acad. Sci. USA 93: 8083-8088, 1996). In the present study, we used the two-microelectrode voltage-clamp technique to measure whole cell K+ currents in Xenopus oocytes, and we further characterized the enhanced sensitivity of ROMK2 to glibenclamide by CFTR. Glibenclamide inhibited K+ currents by 56% in oocytes expressing both ROMK2 and CFTR but only 11% in oocytes expressing ROMK2 alone. To examine the role of the first nucleotide binding fold (NBF1) of CFTR in the ROMK2-CFTR interaction, we studied the glibenclamide sensitivity of ROMK2 when coexpressed with CFTR constructs containing mutations in or around the NBF1 domain. In oocytes coinjected with ROMK2 and a truncated construct of CFTR with an intact NBF1 (CFTR-K593X), glibenclamide inhibited K+ currents by 46%. However, in oocytes coinjected with ROMK2 and a CFTR mutant truncated immediately before NBF1 (CFTR-K370X), glibenclamide inhibited K+ currents by 12%. Also, oocytes expressing both ROMK2 and CFTR mutants with naturally occurring NBF1 point mutations, CFTR-G551D or CFTR-A455E, display glibenclamide-inhibitable K+ currents of only 14 and 25%, respectively. Because CFTR mutations that alter the NBF1 domain reduce the glibenclamide sensitivity of the coexpressed ROMK2 channel, we conclude that the NBF1 motif is necessary for the CFTR-ROMK2 interaction that confers sulfonylurea sensitivity.

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15 Also, oocytes expressing both ROMK2 and CFTR mutants with naturally occurring NBF1 point mutations, CFTR-G551D or CFTR-A455E, display glibenclamide-inhibitable Kϩ currents of only 14 and 25%, respectively. Login to comment
69 The oligonucleotides used for mutagenesis were CFTR-G551D:5Ј GAGTGGAGAT- CAACGAG 3Ј, CFTR-A455E:5Ј GTTGTTGGAGGTTGCTGG 3Ј, CFTR-K370X:5Ј GCAATAAACTAAATACAGGATATCTTAC 3Ј, and CFTR-K593X:5Ј CTGTTAACTGATGGCTAGCAAACTAGG 3Ј. Login to comment
84 To test our hypothesis, we measured the glibenclamide sensitivity of the Kϩ currents (using the experimental protocol described above) when ROMK2 was coexpressed with two engineered CFTR-mutant constructs, CFTR-K593X or CFTR-K370X, or two naturally occurring CFTR-mutant constructs, CFTR-G551D or CFTR-A455E (see Fig. 2). Login to comment
87 In our initial experiments with the mutant CFTR constructs, we coexpressed ROMK2 with either CFTR truncated after NBF1 (CFTR-K593X, Fig. 2) or CFTR truncated before NBF1 (CFTR-K370X, Fig. 2). Login to comment
95 A: two naturally occurring first nucleotide binding folds (NBF1) mutants, CFTR-G551D and CFTR-A455E. Login to comment
96 B: CFTR-K593X, a mutant truncated at residue 593, has an intact NBF1. Login to comment
102 When ROMK2 and CFTR-K370X were coexpressed, the observed Ba2ϩ- sensitive Kϩ currents decreased by only 12.3 Ϯ 3.3% (n ϭ 12) after oocytes were exposed to glibenclamide. Login to comment
104 Next, we coexpressed ROMK2 with naturally occurring CFTR mutations within NBF1 (CFTR-G551D or CFTR-A455E). Login to comment
110 Sensitivity of CFTR Cl- currents to glibenclamide Construct Whole Cell Current, nA %Inhibition By Glibenclamide n P CFTR-WT 560Ϯ150 51.9 9 CFTR-K593X 190Ϯ31 50.1 8 NS CFTR-K370X 183Ϯ85 44.1 5 NS CFTR-G551D 334Ϯ80 49.6 7 NS CFTR-A455E 299Ϯ27 63.2 5 NS Uninjected 26Ϯ10 0 5 0.02 Values are means Ϯ SE; n is no. of experiments. Login to comment
120 Effect of glibenclamide on Ba2ϩ-sensitive currents for ROMK2 coexpressed with CFTR mutants CFTR-K593X and CFTR-G551D. Login to comment
121 Time course showing whole cell currents at Vhold ϭ -60 mV for Xenopus oocytes expressing ROMK2:CFTR-K593X (A) and ROMK2: CFTR-G551D (B) obtained using 2-microelectrode voltage-clamp techniques. Login to comment
128 Average Ba2ϩ-sensitive whole cell currents for each condition are as follows: ROMK2 alone ϭ 11.35 Ϯ 3.3 µA, ROMK2:CFTR-WT ϭ 8.29 Ϯ 0.9 µA, ROMK2:CFTR-G551D ϭ 5.57 Ϯ 0.66 µA, ROMK2:CFTR-K593X ϭ 2.37 Ϯ 0.7 µA, ROMK2: A455E ϭ 6.26 Ϯ 1.39 µA, and ROMK2:K370X ϭ 5.57 Ϯ 0.66 µA. A455E (Fig. 2). Login to comment
129 Coexpressing ROMK2 with CFTR-A455E resulted in Ba2ϩ-sensitive outward currents that were not significantly inhibited by glibenclamide (n ϭ 10) (Fig. 4). Login to comment
131 The data from oocytes coexpressed with ROMK2 and either CFTR-G551D or CFTR-A455E demonstrate that at least two amino acids in NBF1 are necessary for the ROMK2-CFTR interaction. Login to comment
9 Also, oocytes expressing both ROMK2 and CFTR mutants with naturally occurring NBF1 point mutations, CFTRG551D or CFTR-A455E, display glibenclamide-inhibitable K1 currents of only 14 and 25%, respectively. Login to comment
62 The oligonucleotides used for mutagenesis were CFTR-G551D:58 GAGTGGAGAT- CAACGAG 38, CFTR-A455E:58 GTTGTTGGAGGTTGCTGG 38, CFTR-K370X:58 GCAATAAACTAAATACAGGATATCTTAC 38, and CFTR-K593X:58 CTGTTAACTGATGGCTAGCAAACTAGG 38. Login to comment
77 To test our hypothesis, we measured the glibenclamide sensitivity of the K1 currents (using the experimental protocol described above) when ROMK2 was coexpressed with two engineered CFTR-mutant constructs, CFTR-K593X or CFTR-K370X, or two naturally occurring CFTR-mutant constructs, CFTR-G551D or CFTR-A455E (see Fig. 2). Login to comment
123 The data from oocytes coexpressed with ROMK2 and either CFTR-G551D or CFTR-A455E demonstrate that at least two amino acids in NBF1 are necessary for the ROMK2-CFTR interaction. Login to comment

[hide] Cystic fibrosis: gene therapy or preventive gene t... Gene Ther. 1997 Oct;4(10):1001-3. Drittanti L, Masciovecchio MV, Gabbarini J, Vega M
Cystic fibrosis: gene therapy or preventive gene transfer?
Gene Ther. 1997 Oct;4(10):1001-3., [PMID:9415304]

Abstract [show]

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13 Although mild mutations like A455E can significantlyference between 'being the cause of` and 'being interactive with` refers to the duration of the functional inter- delay arrival of the PNR, mutant CFTR (including A455E) cannot avoid the lung reaching the PNR nor progressingaction between the elements in play, namely CFTR and CF. Login to comment
22 According to the epidemiological data, the com-A455E mutations) up to a point where further progression of the phenotype is independent of the CFTR mon rate of death for lung disease CF patients is rn = 15% per year; putting the PNR roughly around at least 6-7activity (or the mutation on the Cftr).1-4 Based on our data, which indicate that the CFTR would be noninter- years before death.1 The 6-7-year span of the lung disease covers greater than 50% of the life span (approximatelyactive throughout the course of the disease it causes, we postulate a new model describing the course of CF. Login to comment
31 a mild A455E-like lung CF pathway is the time needed for reaching the PNR. Login to comment
32 Beyond the PNR both kinetics areThe concept of PNR has been derived from epidemiological evidence.1 As its biological nature has not been the same.1,3 Therefore, for a young presymtomatic CF lung, a delay in the PNR would mimic the differencecharacterised, a precise definition of the border between CF disease and lung disease based on clinical data is so far between developing a severe CF phenotype (like ⌬F508) or developing a mild CF phenotype (like A455E). Login to comment
16 Although mild mutations like A455E can significantly ference between 'being the cause of` and 'being interactive with` refers to the duration of the functional inter- delay arrival of the PNR, mutant CFTR (including A455E) cannot avoid the lung reaching the PNR nor progressing action between the elements in play, namely CFTR and CF. Login to comment
25 According to the epidemiological data, the com- A455E mutations) up to a point where further progression of the phenotype is independent of the CFTR mon rate of death for lung disease CF patients is rn = 15% per year; putting the PNR roughly around at least 6-7 activity (or the mutation on the Cftr).1-4 Based on our data, which indicate that the CFTR would be noninter- years before death.1 The 6-7-year span of the lung disease covers greater than 50% of the life span (approximately active throughout the course of the disease it causes, we postulate a new model describing the course of CF. Login to comment
34 a mild A455E-like lung CF pathway is the time needed for reaching the PNR. Login to comment
35 Beyond the PNR both kinetics are The concept of PNR has been derived from epidemiological evidence.1 As its biological nature has not been the same.1,3 Therefore, for a young presymtomatic CF lung, a delay in the PNR would mimic the difference characterised, a precise definition of the border between CF disease and lung disease based on clinical data is so far between developing a severe CF phenotype (like DF508) or developing a mild CF phenotype (like A455E). Login to comment

[hide] Modeling of nucleotide binding domains of ABC tran... J Bioenerg Biomembr. 1997 Oct;29(5):503-24. Bianchet MA, Ko YH, Amzel LM, Pedersen PL
Modeling of nucleotide binding domains of ABC transporter proteins based on a F1-ATPase/recA topology: structural model of the nucleotide binding domains of the cystic fibrosis transmembrane conductance regulator (CFTR).
J Bioenerg Biomembr. 1997 Oct;29(5):503-24., [PMID:9511935]

Abstract [show]
Members of the ABC transporter superfamily contain two nucleotide binding domains. To date, the three dimensional structure of no member of this super-family has been elucidated. To gain structural insight, the known structures of several other nucleotides binding proteins can be used as a framework for modeling these domains. We have modeled both nucleotide binding domains of the protein CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) using the two similar domains of mitochondrial F1-ATPase. The models obtained, provide useful insights into the putative functions of these domains and their possible interaction as well as a rationale for the basis of Cystic Fibrosis causing mutations. First, the two nucleotide binding domains (folds) of CFTR are each predicted to span a 240-250 amino acid sequence rather than the 150-160 amino acid sequence originally proposed. Second, the first nucleotide binding fold, is predicted to catalyze significant rates of ATP hydrolysis as a catalytic base (E504) resides near the y phosphate of ATP. This prediction has been verified experimentally [Ko, Y.H., and Pedersen, P.L. (1995) J. Biol. Chem. 268, 24330-24338], providing support for the model. In contrast, the second nucleotide binding fold is predicted at best to be a weak ATPase as the glutamic acid residue is replaced with a glutamine. Third, F508, which when deleted causes approximately 70% of all cases of cystic fibrosis, is predicted to lie in a cleft near the nucleotide binding pocket. All other disease causing mutations within the two nucleotide binding domains of CFTR either reside near the Walker A and Walker B consensus motifs in the heart of the nucleotide binding pocket, or in the C motif which lies outside but near the nucleotide binding pocket. Finally, the two nucleotide binding domains of CFTR are predicted to interact, and in one of the two predicted orientations, F508 resides near the interface. This is the first report where both nucleotide binding domains of an ABC transporter and their putative domain-domain interactions have been modeled in three dimensions. The methods and the template used in this work can be used to analyze the structures and function of the nucleotide binding domains of all other members of the ABC transporter super-family.

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34 Other missense mutations are found in or near the motif GX4GK[T/S], i.e., A455E and G458V. Login to comment
360 The CFTR NBD1 model that results (Fig. 6) gathers the disease causing mutations in three different clusters: (1) mutations affecting the nucleotide binding pocket and the putative general base: A455E, G458V, E504Q AI507 AF508 P574H; (2) mutations in motif C which are probably related to an interaction with region D: S549[R,N,I] G551[S,D], R553Q; and (3) mutations within or near motif B, L558S, A559T, R560T, Y563N and mutations S492F and G480C. Login to comment

[hide] CFTR: domains, structure, and function. J Bioenerg Biomembr. 1997 Oct;29(5):443-51. Devidas S, Guggino WB
CFTR: domains, structure, and function.
J Bioenerg Biomembr. 1997 Oct;29(5):443-51., [PMID:9511929]

Abstract [show]
Mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) cause cystic fibrosis (CF) (Collins, 1992). Over 500 naturally occurring mutations have been identified in CF gene which are located in all of the domains of the protein (Kerem et al., 1990; Mercier et al., 1993; Ghanem et al., 1994; Fanen et al., 1992; Ferec et al., 1992; Cutting et al., 1990). Early studies by several investigators characterized CFTR as a chloride channel (Anderson et al.; 1991b,c; Bear et al., 1991). The complex secondary structure of the protein suggested that CFTR might possess other functions in addition to being a chloride channel. Studies have established that the CFTR functions not only as a chloride channel but is indeed a regulator of sodium channels (Stutts et al., 1995), outwardly rectifying chloride channels (ORCC) (Gray et al., 1989; Garber et al., 1992; Egan et al., 1992; Hwang et al., 1989; Schwiebert et al., 1995) and also the transport of ATP (Schwiebert et al., 1995; Reisin et al., 1994). This mini-review deals with the studies which elucidate the functions of the various domains of CFTR, namely the transmembrane domains, TMD1 and TMD2, the two cytoplasmic nucleotide binding domains, NBD1 and NBD2, and the regulatory, R, domain.

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121 For example, two mutations,A455E and G55ID, are associated with milder and more severe forms of CF, respectively. Login to comment
122 When these two mutations are studied in airway cells, both could still conduct Cl- , however, only CFTR bearing the A455E mutation retained the function of regulating ORCC. Login to comment

[hide] Halide permeation in wild-type and mutant cystic f... J Gen Physiol. 1997 Oct;110(4):341-54. Tabcharani JA, Linsdell P, Hanrahan JW
Halide permeation in wild-type and mutant cystic fibrosis transmembrane conductance regulator chloride channels.
J Gen Physiol. 1997 Oct;110(4):341-54., [PMID:9379167]

Abstract [show]
Permeation of cystic fibrosis transmembrane conductance regulator (CFTR) Cl channels by halide ions was studied in stably transfected Chinese hamster ovary cells by using the patch clamp technique. In cell-attached patches with a high Cl pipette solution, the CFTR channel displayed outwardly rectifying currents and had a conductance near the membrane potential of 6.0 pS at 22 degrees C or 8.7 pS at 37 degrees C. The current-voltage relationship became linear when patches were excised into symmetrical, -tris(hydroxymethyl)methyl-2-aminomethane sulfonate (TES)-buffered solutions. Under these conditions, conductance increased from 7.0 pS at 22 degrees C to 10.9 pS at 37 degrees C. The conductance at 22 degrees C was approximately 1.0 pS higher when TES and HEPES were omitted from the solution, suggesting weak, voltage-independent block by pH buffers. The relationship between conductance and Cl activity was hyperbolic and well fitted by a Michaelis-Menten-type function having a of approximately 38 mM and maximum conductance of 10 pS at 22 degrees C. Dilution potentials measured with NaCl gradients indicated high anion selectivity (P/P = 0.003-0.028). Biionic reversal potentials measured immediately after exposure of the cytoplasmic side to various test anions indicated P(1.8) > P(1. 3) > P(1.0) > P(0.17), consistent with a "weak field strength" selectivity site. The same sequence was obtained for external halides, although inward F flow was not observed. Iodide currents were protocol dependent and became blocked after 1-2 min. This coincided with a large shift in the (extrapolated) reversal potential to values indicating a greatly reduced I/Cl permeability ratio (P/P< 0.4). The switch to low I permeability was enhanced at potentials that favored Cl entry into the pore and was not observed in the R347D mutant, which is thought to lack an anion binding site involved in multi-ion pore behavior. Interactions between Cl and I ions may influence I permeation and be responsible for the wide range of P/P ratios that have been reported for the CFTR channel. The low P/P ratio usually reported for CFTR only occurred after entry into an altered permeability state and thus may not be comparable with permeability ratios for other anions, which are obtained in the absence of iodide. We propose that CFTR displays a "weak field strength" anion selectivity sequence.

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21 Mutations in CFTR that cause it to be mislocalized (i.e., ⌬F508) or unresponsive (i.e., G551D) are associated with severe forms of cystic fibrosis, whereas mutations that only partially reduce CFTR conductance (R347P,H, Sheppard et al., 1993; Tabcharani et al., 1993), open probability (R117H, Sheppard et al., 1993; Becq et al., 1994; intracellular loop IV mutants, Seibert et al., 1996), or processing (A455E, Sheppard et al., 1995) are associated with milder symptoms. Login to comment
24 Mutations in CFTR that cause it to be mislocalized (i.e., DF508) or unresponsive (i.e., G551D) are associated with severe forms of cystic fibrosis, whereas mutations that only partially reduce CFTR conductance (R347P,H, Sheppard et al., 1993; Tabcharani et al., 1993), open probability (R117H, Sheppard et al., 1993; Becq et al., 1994; intracellular loop IV mutants, Seibert et al., 1996), or processing (A455E, Sheppard et al., 1995) are associated with milder symptoms. Login to comment

[hide] Correlation between nasal potential difference mea... Eur Respir J. 1997 Sep;10(9):2018-22. Ho LP, Samways JM, Porteous DJ, Dorin JR, Carothers A, Greening AP, Innes JA
Correlation between nasal potential difference measurements, genotype and clinical condition in patients with cystic fibrosis.
Eur Respir J. 1997 Sep;10(9):2018-22., [PMID:9311495]

Abstract [show]
In cystic fibrosis (CF), the clinical condition of patients correlates poorly with genotype. One possible explanation is that clinical status is influenced by net preserved chloride secretion rather than the CF mutation. We tested the relationships between residual chloride secretion, as measured by nasal potential difference (PD) and the type of mutation (genotypes expressing apical cystic fibrosis transmembrane conductance regulator (CFTR) protein versus those that do not) and clinical status. Twenty two CF patients (mean age 25.7 yrs, 11 females and 11 males, mean forced expiratory volume in one second (FEV1) 53.1% of predicted) with defined genotypes were recruited. Nasal PD was measured using a standard protocol involving the perfusion of the nasal epithelium with a sodium channel blocker (amiloride), followed by a solution of low chloride and finally with isoprenaline. Patients with apical CFTR protein showed higher residual chloride secretion than those without (amiloride to isoprenaline value of 4.59 and 0.56 mV, respectively, p = 0.01). There was no correlation between mutation type and clinical condition. When these patients were recategorized as "high" (> 10 mV amiloride to isoprenaline response) or "low" (10 mV or less) chloride secretors, we found that the former group had a significantly higher FEV1 (67.7 versus 48.3% pred) and a better pulmonary radiological score (4.14 versus 7.07, by Northern scoring system). These results suggest that some cystic fibrosis patients, regardless of genotype, have an ability to secrete chloride when stimulated with chloride secretatagogues, and this is correlated with a better lung function. These results also have implications for the use of potential difference measurements in novel cystic fibrosis transmembrane conductance regulator replacement trials.

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25 Homozygotes for ∆F508 mutation have been found to have a greater incidence of pancreatic insufficiency, worse lung function and higher mortality compared to other genotypes [2, 3] while isolated mutations such as A455E are associated with a mild clinical course [4]. Login to comment
60 Data analysis Patients were divided into two groups, according to genotype: 1) mutations that fail to generate significant apical membrane protein (∆F508/∆F508, ∆F508/ W1282X, ∆F508/Q493X) and 2) mutations where gene product is present in the apical membrane (∆F508/G551D, ∆F508/ A455E, ∆F508/R117H, G551D/G551D) [12]. Login to comment
123 All, however, were pancreatic insufficient and were colonized by Pseudomonas spp. The only two pancreatic sufficient subjects were those who also showed the two highest values for chloride secretion ( genotypes A455E/∆F508 and R117H/∆F508). Login to comment

[hide] Newborn screening for cystic fibrosis in Wisconsin... Pediatrics. 1997 Jun;99(6):819-24. Gregg RG, Simantel A, Farrell PM, Koscik R, Kosorok MR, Laxova A, Laessig R, Hoffman G, Hassemer D, Mischler EH, Splaingard M
Newborn screening for cystic fibrosis in Wisconsin: comparison of biochemical and molecular methods.
Pediatrics. 1997 Jun;99(6):819-24., [PMID:9164776]

Abstract [show]
OBJECTIVES: To evaluate neonatal screening for cystic fibrosis (CF), including study of the screening procedures and characteristics of false-positive infants, over the past 10 years in Wisconsin. An important objective evolving from the original design has been to compare use of a single-tier immunoreactive trypsinogen (IRT) screening method with that of a two-tier method using IRT and analyses of samples for the most common cystic fibrosis transmembrane regulator (CFTR) (DeltaF508) mutation. We also examined the benefit of including up to 10 additional CFTR mutations in the screening protocol. METHODS: From 1985 to 1994, using either the IRT or IRT/DNA protocol, 220 862 and 104 308 neonates, respectively, were screened for CF. For the IRT protocol, neonates with an IRT >/=180 ng/mL were considered positive, and the standard sweat chloride test was administered to determine CF status. For the IRT/DNA protocol, samples from the original dried-blood specimen on the Guthrie card of neonates with an IRT >/=110 ng/mL were tested for the presence of the DeltaF508 CFTR allele, and if the DNA test revealed one or two DeltaF508 alleles, a sweat test was obtained. RESULTS: Both screening procedures had very high specificity. The sensitivity tended to be higher with the IRT/DNA protocol, but the differences were not statistically significant. The positive predictive value of the IRT/DNA screening protocol was 15.2% compared with 6.4% if the same samples had been screened by the IRT method. Assessment of the false-positive IRT/DNA population revealed that the two-tier method eliminates the disproportionate number of infants with low Apgar scores and also the high prevalence of African-Americans identified previously in our study of newborns with high IRT levels. We found that 55% of DNA-positive CF infants were homozygous for DeltaF508 and 40% had one DeltaF508 allele. Adding analyses for 10 more CFTR mutations has only a small effect on the sensitivity but is likely to add significantly to the cost of screening. CONCLUSIONS: Advantages of the IRT/DNA protocol over IRT analysis include improved positive predictive value, reduction of false-positive infants, and more rapid diagnosis with elimination of recall specimens.

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152 DNA Analysis of Genotyped CF Patients in the US* n Percent ⌬F508 12701 67.7 G542X 403 2.2 G551D 357 1.9 W1282X 240 1.3 N1303K 223 1.2 R553X 157 0.8 3849 ϩ 10kbC 3 T 102 0.5 621 ϩ 1G 3 T 147 0.8 1717 - 1G 3 A 101 0.5 R117H 101 0.5 R334W 36 0.2 ⌬I507 42 0.2 R347P 37 0.2 R560T 23 0.1 R1162X 44 0.2 2789 ϩ 5G 3 A 25 0.1 A455E 16 0.1 3120 ϩ IG 3 A 14 0.0 S549N 12 0.0 711 ϩ IG 3 T 9 0.0 Other 178 0.9 Unidentified 3814 20.3 Total 18782 99.7† Patient Genotypes Allele 1/Allele 2 n % of Genotype ⌬F508/⌬F508 4573 48.7 ⌬F508/Known 1511 16.1 ⌬F508/Unknown 2044 21.8 Known/unknown 310 3.3 Known/known 223 2.4 Unknown/unknown 730 7.8 Total 9391 100.0 *Data from Cystic Fibrosis Registry, 1995; Annual Report. Login to comment
147 DNA Analysis of Genotyped CF Patients in the US* n Percent DF508 12701 67.7 G542X 403 2.2 G551D 357 1.9 W1282X 240 1.3 N1303K 223 1.2 R553X 157 0.8 3849 1 10kbC 3 T 102 0.5 621 1 1G 3 T 147 0.8 1717 2 1G 3 A 101 0.5 R117H 101 0.5 R334W 36 0.2 DI507 42 0.2 R347P 37 0.2 R560T 23 0.1 R1162X 44 0.2 2789 1 5G 3 A 25 0.1 A455E 16 0.1 3120 1 IG 3 A 14 0.0 S549N 12 0.0 711 1 IG 3 T 9 0.0 Other 178 0.9 Unidentified 3814 20.3 Total 18782 99.7ߤ Patient Genotypes Allele 1/Allele 2 n % of Genotype DF508/DF508 4573 48.7 DF508/Known 1511 16.1 DF508/Unknown 2044 21.8 Known/unknown 310 3.3 Known/known 223 2.4 Unknown/unknown 730 7.8 Total 9391 100.0 *Data from Cystic Fibrosis Registry, 1995; Annual Report. Login to comment

[hide] Identification of common cystic fibrosis mutations... Am J Hum Genet. 1997 May;60(5):1122-7. Macek M Jr, Mackova A, Hamosh A, Hilman BC, Selden RF, Lucotte G, Friedman KJ, Knowles MR, Rosenstein BJ, Cutting GR
Identification of common cystic fibrosis mutations in African-Americans with cystic fibrosis increases the detection rate to 75%.
Am J Hum Genet. 1997 May;60(5):1122-7., [PMID:9150159]

Abstract [show]
Cystic fibrosis (CF)--an autosomal recessive disorder caused by mutations in CF transmembrane conductance regulator (CFTR) and characterized by abnormal chloride conduction across epithelial membranes, leading to chronic lung and exocrine pancreatic disease--is less common in African-Americans than in Caucasians. No large-scale studies of mutation identification and screening in African-American CF patients have been reported, to date. In this study, the entire coding and flanking intronic sequence of the CFTR gene was analyzed by denaturing gradient-gel electrophoresis and sequencing in an index group of 82 African-American CF chromosomes to identify mutations. One novel mutation, 3120+1G-->A, occurred with a frequency of 12.3% and was also detected in a native African patient. To establish frequencies, an additional group of 66 African-American CF chromosomes were screened for mutations identified in two or more African-American patients. Screening for 16 "common Caucasian" mutations identified 52% of CF alleles in African-Americans, while screening for 8 "common African" mutations accounted for an additional 23%. The combined detection rate of 75% was comparable to the sensitivity of mutation analysis in Caucasian CF patients. These results indicate that African-Americans have their own set of "common" CF mutations that originate from the native African population. Inclusion of these "common" mutations substantially improves CF mutation detection rates in African-Americans.

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39 Mutation Analysis All patients were screened for the AF508 mutation and 15 common Caucasian CF mutations using a reverse dot strip hybridization system (Kawasaki et al. 1993) (R117H, 621+1G--T, R334W, R347P, A455E, A1507, 1717-1G-+A, G542X, S549N, GSS1D, R553X, R560T, 3849+10kbC-+T, W1282X, and N1303K) (Welsh et al. 1995) and a deep intron 11 splice-site mutation, 1811+1.6kbA-+G (Chillon et al. 1995). Login to comment
86 The most common muta- Table 2 Distribution of CF Mutations in African-American and U.S.-Caucasian CF Patients African-American U.S. Caucasiana Mutation (n= 148) % (n = 8,714) % Caucasian mutations: AF508 71 48 5,769 66.2 R117H 0 0 47 .5 621+1 G--T 0 0 68 .8 R334W 1 .7 7 .1 R347P 0 0 24 .3 A455E 0 0 5 .1 AI507 1 .7 10 .1 1717-1 G-IA 1 .7 39 .5 G542X 1 .7 204 2.3 S549N 1 .7 4 .1 GS51D 1 .7 173 2.0 R553X (Caucasian)b 0 0 87 1.0 R560T 0 0 16 .2 3849+10kb C-T 0 0 51 .6 W1282X 0 0 235 2.7 N1303K 0 0 116 1.3 Subtotal 77 52 6,855 78.7 African-American mutations: 405+3 A-C 2 1.4 ... ... 444delA 1 .7 ... ... G480C 2 1.4 ... ... R553X (African)b 3 2.0 ... ... A559T 3 2.0 ... ... 2307insA 3 2.0 ... ... 3120+1 GC-A 18 12.2 ... ... S1255X 2 1.4 ... ... Subtotal 34 23 ... ... Total 111 75.0 6,855 78.7 NOTE.-Percentages are rounded. Login to comment
40 Mutation Analysis All patients were screened for the AF508 mutation and 15 common Caucasian CF mutations using a reverse dot strip hybridization system (Kawasaki et al. 1993) (R117H, 621+1G--T, R334W, R347P, A455E, A1507, 1717-1G-+A, G542X, S549N, GSS1D, R553X, R560T, 3849+10kbC-+T, W1282X, and N1303K) (Welsh et al. 1995) and a deep intron 11 splice-site mutation, 1811+1.6kbA-+G (Chillon et al. 1995). Login to comment
87 The most common muta- Table 2 Distribution of CF Mutations in African-American and U.S.-Caucasian CF Patients African-American U.S. Caucasiana Mutation (n= 148) % (n = 8,714) % Caucasian mutations: AF508 71 48 5,769 66.2 R117H 0 0 47 .5 621+1 G--T 0 0 68 .8 R334W 1 .7 7 .1 R347P 0 0 24 .3 A455E 0 0 5 .1 AI507 1 .7 10 .1 1717-1 G-IA 1 .7 39 .5 G542X 1 .7 204 2.3 S549N 1 .7 4 .1 GS51D 1 .7 173 2.0 R553X (Caucasian)b 0 0 87 1.0 R560T 0 0 16 .2 3849+10kb C-T 0 0 51 .6 W1282X 0 0 235 2.7 N1303K 0 0 116 1.3 Subtotal 77 52 6,855 78.7 African-American mutations: 405+3 A-C 2 1.4 ... ... 444delA 1 .7 ... ... G480C 2 1.4 ... ... R553X (African)b 3 2.0 ... ... A559T 3 2.0 ... ... 2307insA 3 2.0 ... ... 3120+1 GC-A 18 12.2 ... ... S1255X 2 1.4 ... ... Subtotal 34 23 ... ... Total 111 75.0 6,855 78.7 NOTE.-Percentages are rounded. Login to comment

[hide] Relationship between airway ion transport and a mi... Am J Respir Crit Care Med. 1997 May;155(5):1684-9. Walker LC, Venglarik CJ, Aubin G, Weatherly MR, McCarty NA, Lesnick B, Ruiz F, Clancy JP, Sorscher EJ
Relationship between airway ion transport and a mild pulmonary disease mutation in CFTR.
Am J Respir Crit Care Med. 1997 May;155(5):1684-9., [PMID:9154877]

Abstract [show]
Patients with cystic fibrosis (CF) display defects in airway ion transport, but the influence of airway transport phenotype on improved prognosis is not known. We studied airway bioelectric properties in five CF patients with the rare A455E mutation that is associated with mild pulmonary disease. We also evaluated five patients possessing premature truncation mutations (G542X and R553X) for which an association with mild pulmonary disease has not been as well established. We found no evidence in vivo that a mild lung disease mutation in the CF transmembrane regulator gene (CFTR) led to correction or partial correction of: (1) unstimulated Cl- secretion; (2) beta-agonist-activated Cl- secretion; (3) basal sodium reabsorption; or (4) amiloride-sensitive airway sodium transport. Early phase therapeutic trials in CF, including human gene transfer trials, rely heavily on improvements in airway potential difference to identify promising interventions and an improved prognosis. Based on our findings in a naturally occurring group of CF patients with an improved pulmonary prognosis (A455E), one can argue that marked clinical benefit might be possible without any improvement whatsoever in airway bioelectric phenotype. Moreover, if genetic modifiers exist that influence the severity of a particular CFTR mutation (e.g., A455E), these may be independent of human airway Cl-secretion in vivo, since we detected minimal Cl--secretory responses in patients with A455E.

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1 We studied airway bioelectric properties in five CF patients with the rare A455E mutation that is associated with mild pulmonary disease. Login to comment
5 Based on our findings in a naturally occurring group of CF patients with an improved pulmonary prognosis (A455E), one can argue that marked clinical benefit might be possible without any improvement whatsoever in airway bioelectric phenotype. Login to comment
6 Moreover, if genetic modifiers exist that influence the severity of a particular CFTR mutation (e.g., A455E), these may be independent of human airway Cl secretion in vivo, since we detected minimal Cl- -secretory responses in patients with A455E. Login to comment
45 Expression of CFTR in COS-7 (Simian Kidney) Cells Expression of wild type, AF508 or A445E CFTR under the regulatory control of the 17 promoter was studied with the pTM1 vector (gift of Dr. B. Moss, of the National Institutes of Health; the A455E construct in this vector backbone was a generous gift of Dr. M. Welsh of the University of Iowa). Login to comment
59 RESULTS Table 1 summarizes clinical features of the A455E, G542X, and R553X CF patients we studied. Login to comment
62 Taken together, there had been a total of 10 hospital admissions for intravenous antibiotic therapy among the A455E patients, and more than 36 admissions among the patients with truncation mutations. Login to comment
67 Decisions regard- -10 26t5 mV -39*9 mVtt -57±5 mVtt -43*9 mVtt Control G542X or R553X A544E AF508 B 50 40 • C A PD 30 • (mV) • 20 • •• 10 ' • • o - t----------------------------- aj J0 mVtt -27±8 mVtt Control G542X or R553X A455E AF508 C -40 -30 1686 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL. 155 1997 A -60 -50 • t 1 ' PD max -40 I (mV) • • • -30 • • s-20 to mV L - - i--- --- - -- -------loses A Amilo,id Amilonde Amiloride Low CI' Low Cl* fenol lomV L l0 Sea --------------^--------- --------t- - --- -- - --------- l0 mV L ------^--- --------Y- -^ t t lOmV L 10Sa. Login to comment
71 Genotypes of the patients shown include B:A455E/621 + 1 G-*T; C:AF508/A455E; and D:R553X/G542X. Login to comment
74 Figure 1B and C show tracings from compound heterozygotes for the A455E mutation. Login to comment
77 The remainder of patients with the A455E mutation exhibited no response to low Cl- /isoproterenol, as in the tracing in Figure I.C. Figure 1D shows a tracing from a patient homozygous for truncation mutations within CFTR (G542X/R553X). Login to comment
80 Figure 2 shows a summary of the data from patients and healthy controls in the study, and describes the baseline PD during perfusion with lactated Ringer's solution (Figure 2A), -20 APD (mv) • -10 tl • 0•------'------------------s---------------------------------- --- 10 12t7 mV -2:4 rVtt -4t8 mVtt -5)mVtt Control G542X or R553X A455E AF508 Figure 2. Login to comment
89 In B, both A455E and AF508 differed from the truncation mutation group (p < 0.01). Login to comment
92 When data from each experimental group are taken together, neither A455E patients nor those with truncation mutations showed evidence of either a Cl- -secretory response (Figure 2C) or a suggestion of normalization of this aspect of the PD measurement. Login to comment
93 In the A455E patients, the maximal PD during perfusion with lactated Ringer's solution and the change after amiloride were well within the range anticipated for the general CF population (Figure 2A and B; [6-21]). Login to comment
94 In the patients with CFTR truncations G542X or R553X, the magnitude of the amiloride-sensitive PD (Figure 2B) was less than in A455E or AF508 patients, although these measurements were still highly useful in discriminating all CF patient groups from individuals without CF (p < 0.01). Login to comment
98 On the basis of these in vivo experiments, we were interested in studying the in vitro activity of CFTR containing the A455E mutation. Login to comment
99 During in vitro overexpression in heterologous cells, the A455E mutation has been reported to exhibit partial Cl- -channel activity (7). Login to comment
101 The results indicate that cAMP-dependent increases in halide permeability occur after A455E CFTR overexpression in vitro, and are intermediate between halide permeability with wild-type and AF508 CFTR. Login to comment
102 DISCUSSION The A455E mutation in CFTR has been associated with improved FEV1 and FVC, a reduced incidence of pulmonary colonization by Pseudomonas aeruginosa, better exocrine pancreatic function, residual Cl- -channel activity in vitro, and improved overall prognosis in CF (2-7). Login to comment
106 The incidence of A455E in both populations is believed to be based on a genetic founder effect. Login to comment
109 However, our results suggest that whether it is the A455E mutation itself or (as yet undetermined) interactions with other genes that lead to mild lung disease, the mitigating factor is independent of large improvements in either transepithelial Cl- or Na+ transport, since no such improvements were observed in our experiments. Login to comment
111 It.ie not known whether the airway bioelectric measurement is sufficiently sensitive to identify a lower limit of gene transfer necessary to provide benefit in this setting, --A-- A455E (11/53) 0 eF508 (0/27) CFTR (42/42) S S S S S 0 0 S SCl C) er U) 10 h CD 0) SECONDS Figure 3. Login to comment
112 Functional assay of cAMP-mediated halide permeability in COS-7 cells transiently expressing wild-type (open circles), A455E (open triangles), or AF508 CFTR (filled diamonds). Login to comment
117 Approximately 20% of A455E cells (11 of 53) had a detectable cAMP response comparable with that of the wild-type CFTR. Login to comment
118 Each curve is the mean ± SEM of responding (wild-type CFTR or A455E) or total (ÁF508) cells. Login to comment
119 A455E responses differed from those of AF508 (p < 0.001). Login to comment
124 We also studied the A455E mutation in a recombinant overexpression system used to analyze the function of CFTR mutations (24-27). Login to comment
125 The data presented in Figure 3 indicate that A455E retains residual activity when studied in vitro. Login to comment
127 Together with our in vivo experiments, this result suggests that A455E is active following overexpression, but that the activity in vivo is not detectable by the nasal PD assay. Login to comment
129 First, the nasal PD, the best available method for studying the CF bioelectric phenotype in vivo, may not be sufficiently sensitive to detect clinically important improvements in Cl- secretion in a small number of CF patients with an improved prognosis (i.e, five individuals with the A455E mutation). Login to comment
131 Alternatively, since the levels of A455E J m m m A LL w y w V z 51 dequench cAMP AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL. 155 1997 mRNA or protein in vivo are not known, it is possible that previous in vitro overexpression studies of A455E (and the results shown in Figure 3) reflect a phenomenon that does not predict activity of the mutation in vivo. Login to comment
132 For example, it is possible that detectable A455E C1 - -channel activity in isolated cells or membrane patches depends on a very high level of protein expression that is absent in vivo. Login to comment
133 Because PD measurements detect Cl- secretion across polarized epithelium, studies of A455E in nonpolarized cells grown on plastic might have quite different results from the in vivo situation. Login to comment
44 Expression of CFTR in COS-7 (Simian Kidney) Cells Expression of wild type, AF508 or A445E CFTR under the regulatory control of the 17 promoter was studied with the pTM1 vector (gift of Dr. B. Moss, of the National Institutes of Health; the A455E construct in this vector backbone was a generous gift of Dr. M. Welsh of the University of Iowa). Login to comment
58 RESULTS Table 1 summarizes clinical features of the A455E, G542X, and R553X CF patients we studied. Login to comment
61 Taken together, there had been a total of 10 hospital admissions for intravenous antibiotic therapy among the A455E patients, and more than 36 admissions among the patients with truncation mutations. Login to comment
66 Decisions regard- -10 26t5 mV -39*9 mVtt -57&#b1;5 mVtt -43*9 mVtt Control G542X or R553X A544E AF508 B 50 40 ߦ C A PD 30 ߦ (mV) ߦ 20 ߦ ߦ ߦ 10 ' ߦ ߦ o - t---------------------------- - aj J0 mVtt -27&#b1;8 mVtt Control G542X or R553X A455E AF508 C -40 -30 1686 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL. 155 1997 A -60 -50 ߦ t 1 ' PD max -40 I (mV) ߦ ߦ ߦ -30 ߦ ߦ s -20 to mV L - - i--- --- - -- -------loses A Amilo,id Amilonde Amiloride Low CI' Low Cl* fenol lomV L l0 Sea --------------^--------- --------t- - --- -- - --------- l0 mV L ------^--- --------Y- -^ t t lOmV L 10Sa. Login to comment
70 Genotypes of the patients shown include B:A455E/621 + 1 G-*T; C:AF508/A455E; and D:R553X/G542X. Login to comment
73 Figure 1B and C show tracings from compound heterozygotes for the A455E mutation. Login to comment
76 The remainder of patients with the A455E mutation exhibited no response to low Cl- /isoproterenol, as in the tracing in Figure I.C. Figure 1D shows a tracing from a patient homozygous for truncation mutations within CFTR (G542X/R553X). Login to comment
79 Figure 2 shows a summary of the data from patients and healthy controls in the study, and describes the baseline PD during perfusion with lactated Ringer's solution (Figure 2A), -20 APD (mv) ߦ -10 tl ߦ 0ߦ------' ------------------s---------------------------------- --- 10 12t7 mV -2:4 rVtt -4t8 mVtt -5)mVtt Control G542X or R553X A455E AF508 Figure 2. Login to comment
88 In B, both A455E and AF508 differed from the truncation mutation group (p < 0.01). Login to comment
91 When data from each experimental group are taken together, neither A455E patients nor those with truncation mutations showed evidence of either a Cl- -secretory response (Figure 2C) or a suggestion of normalization of this aspect of the PD measurement. Login to comment
97 On the basis of these in vivo experiments, we were interested in studying the in vitro activity of CFTR containing the A455E mutation. Login to comment
100 The results indicate that cAMP-dependent increases in halide permeability occur after A455E CFTR overexpression in vitro, and are intermediate between halide permeability with wild-type and AF508 CFTR. Login to comment
104 The incidence of A455E in both populations is believed to be based on a genetic founder effect. Login to comment
107 However, our results suggest that whether it is the A455E mutation itself or (as yet undetermined) interactions with other genes that lead to mild lung disease, the mitigating factor is independent of large improvements in either transepithelial Cl- or Na+ transport, since no such improvements were observed in our experiments. Login to comment
110 Functional assay of cAMP-mediated halide permeability in COS-7 cells transiently expressing wild-type (open circles), A455E (open triangles), or AF508 CFTR (filled diamonds). Login to comment
115 Approximately 20% of A455E cells (11 of 53) had a detectable cAMP response comparable with that of the wild-type CFTR. Login to comment
116 Each curve is the mean &#b1; SEM of responding (wild-type CFTR or A455E) or total (&#c1;F508) cells. Login to comment
122 We also studied the A455E mutation in a recombinant overexpression system used to analyze the function of CFTR mutations (24-27). Login to comment
123 The data presented in Figure 3 indicate that A455E retains residual activity when studied in vitro. Login to comment
130 For example, it is possible that detectable A455E C1 - -channel activity in isolated cells or membrane patches depends on a very high level of protein expression that is absent in vivo. Login to comment

[hide] Analysis of 16 cystic fibrosis mutations in Mexica... Am J Med Genet. 1997 Apr 14;69(4):380-2. Villalobos-Torres C, Rojas-Martinez A, Villareal-Castellanos E, Cantu JM, Sanchez-Anzaldo FJ, Saiki RK, Barrera-Saldana HA
Analysis of 16 cystic fibrosis mutations in Mexican patients.
Am J Med Genet. 1997 Apr 14;69(4):380-2., [PMID:9098486]

Abstract [show]
We carried out molecular analysis of 80 chromosomes from 40 unrelated Mexican patients with a diagnosis of cystic fibrosis. The study was performed in two PCR steps: a preliminary one to identify mutation delta F508, the most frequent cause of cystic fibrosis worldwide, and the second a reverse dot-blot with allele-specific oligonucleotide probes to detect 15 additional common mutations in the Caucasian population. A frequency of 45% for delta F508 was found, making it the most common in our sample of Mexican patients. Another five mutations (G542X, 3,849 + 10 kb C-->T, N1303K, SN549N, and 621 + 1 G-->T) were detected, and those accounted for 11.25%. The remaining mutations (43.75%) were undetectable with the methodology used.

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60 Mutation Frequency Data and Geographic Distribution of the Mutations Found in 80 Chromosomes From Mexican CF Patients Mutation Northeast n ‫ס‬ 54 Central n ‫ס‬ 16 Western n ‫ס‬ 10 Total n ‫ס‬ 80 CFGAC [1994] (%)n (%) n (%) n (%) n (%) ⌬F508 27 (50) 2 (12.5) 7 (70) 36 (45) 66 G542X 2 (3.7) 2 (12.5) 0 4 (5) 2.4 3849 + 10 kb C→T 1 (1.9) 0 1 (10) 2 (2.5) 0.2 N1303K 0 1 (6.25) 0 1 (1.25) 1.3 S549N 0 1 (6.25) 0 1 (1.25) 0.1 621 + 1 G→T 0 0 1 (10) 1 (1.25) 0.7 Othera 24 (44.4) 10 (62.5) 1 (10) 35 (43.7) Detected 30 (55.6) 6 (37.5) 9 (90) 45 (56.3) a Different from W1282X, R117H, R334W, R347P, A455E, ⌬I507, 1717 - 1 G→T, G551D, R553X, and R560T. Login to comment

[hide] Evidence for safety and efficacy of DOTAP cationic... Gene Ther. 1997 Mar;4(3):210-8. Porteous DJ, Dorin JR, McLachlan G, Davidson-Smith H, Davidson H, Stevenson BJ, Carothers AD, Wallace WA, Moralee S, Hoenes C, Kallmeyer G, Michaelis U, Naujoks K, Ho LP, Samways JM, Imrie M, Greening AP, Innes JA
Evidence for safety and efficacy of DOTAP cationic liposome mediated CFTR gene transfer to the nasal epithelium of patients with cystic fibrosis.
Gene Ther. 1997 Mar;4(3):210-8., [PMID:9135734]

Abstract [show]
In cystic fibrosis (CF), mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene results in defective transepithelial ion transport, leading to life shortening inflammatory lung disease. Before lung studies, we tested the safety and efficacy of gene delivery to the nasal epithelium of CF patients using pCMV-CFTR-DOTAP cationic liposome complex. A single dose of 400 micrograms pCMV-CFTR:2.4 mg DOTAP was administered in a randomised, double-blinded fashion to the nasal epithelium of eight CF patients, with a further eight receiving buffer only. Patients were monitored for signs and symptoms for 2 weeks before treatment and 4 weeks after treatment. Inflammatory cells were quantified in a nasal biopsy taken 3 days after treatment. There was no evidence for excess nasal inflammation, circulating inflammatory markers or other adverse events ascribable to active treatment. Gene transfer and expression were assayed by the polymerase chain reaction. Transgene DNA was detected in seven of the eight treated patients up to 28 days after treatment and vector derived CFTR mRNA in two of the seven patients at +3 and +7 days. Transepithelial ion transport was assayed before and after treatment by nasal potential difference during drug perfusion and by SPQ fluorescence halide ion conductance. Partial, sustained correction of CFTR-related functional changes toward normal values were detected in two treated patients. The level of gene transfer and functional correction were comparable to those reported previously using adenoviral vectors or another DNA-liposome complex, but here were sustained and uncompromised by false positives. These results justify further studies with pCMV-CFTR-DOTAP aimed at treating CF lung disease.

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32 Table 1 Anthropometric data Group Patient Gender Age Genotype FEV1 No (% predicted) Placebo 03 Female 33 ⌬F508/R117H 57 06 Male 27 ⌬F508/⌬F508 55 08 Female 29 ⌬F508/A455E 97 11 Female 42 ⌬F508/Q493X 24 15 Male 30 ⌬F508/R560T 20 16 Female 20 ⌬F508/⌬F508 70 18 Female 27 ⌬F508/⌬F508 21 21 Female 20 ⌬F508/⌬F508 20 Mean (s.d.) 6F, 2M 28.5 (7.1) 51.9 (28.1) Treated 01 Male 31 ⌬F508/G551D 45 05 Female 30 ⌬F508/⌬F508 91 09 Male 32 G551D/G551D 37 10 Female 29 ⌬F508/⌬F508 63 13 Male 16 ⌬F508/⌬F508 55 14 Female 37 ⌬F508/G551D 66 19 Male 23 ⌬F508/W1282X 37 23 Female 21 ⌬F508/G551D 53 Mean (s.d.) 4F, 4M 27.4 (6.8) 55.9 (17.8) and illustrative results shown in Figure 3. Login to comment

[hide] Cystic fibrosis mutation frequencies in upstate Ne... Hum Mutat. 1997;10(6):436-42. Shrimpton AE, Borowitz D, Swender P
Cystic fibrosis mutation frequencies in upstate New York.
Hum Mutat. 1997;10(6):436-42., [PMID:9401006]

Abstract [show]
Upstate New York patients (100) with cystic fibrosis (i.e., 200 CF chromosomes), 72 from the CF center in Syracuse and 28 from a Buffalo CF center, were analyzed for their CF-causing mutations using restriction enzyme digest, single-strand conformation analysis (SSCA), and Heteroduplex (HA) analysis. Polymerase chain reaction (PCR) amplified products from all 27 CFTR exons using primers that included flanking intron junction sequence were investigated. More than 120 known cystic fibrosis transmembrane conductance regulator (CFTR) disease-causing mutations were screened. Four novel CFTR disease-causing mutations were identified (N287Y in exon 6b, 1259insA in exon 8, R1070P in exon 17b, and CF?20kbdel14b-18). A detection rate of 96% of the combined Syracuse and Buffalo population CF chromosomes was obtained.

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84 % Comment 3 G85E 1 1 0.5 4 R117H 1 1 0.5 i4 621 + 1,G>T 1 2 3 1.5 5 711 + 1,G>T 1 1 0.5 6b N287Y 1 1 0.5 Novel 7 1154insTC 2 2 1.0 8 1259insA 1 1 0.5 Novel 9 A455E 1 1 0.5 10 Delta F508 109 39 148 74.0 10 1609delCA 1 1 0.5 Spanish i10 1717-1,G>A 3 3 1.5 11 G542X 2 1 3 1.5 11 G551D 3 3 1.5 11 R553X 4 4 2.0 i12 1898+1,G>A 2 2 1.0 13 2143delT 1 1 0.5 13 2184delA+G>A 1 1 0.5 i14 2789+5,G>A 2 2 1.0 17b R1070P 1 1 0.5 Novel 17b Y1092X(C>A) 2 2 1.0 French Canadian (Rozen et al., 1992) 17b CF?20kbdel 14b-18 1 1 0.5 Novel (Shrimpton and Borowitz, 1997) i19 3849+10kb,C>T 1 1 0.5 20 W1282X 2 2 0.5 Ashkenazi 21 N1303K 3 3 6 3.0 Unknown 4/144 4/56 8/200 4.0 AL. 75 and 81 mMol/L. Login to comment

[hide] Missense mutation R1066C in the second transmembra... Hum Mutat. 1997;10(5):387-92. Casals T, Pacheco P, Barreto C, Gimenez J, Ramos MD, Pereira S, Pinheiro JA, Cobos N, Curvelo A, Vazquez C, Rocha H, Seculi JL, Perez E, Dapena J, Carrilho E, Duarte A, Palacio AM, Nunes V, Lavinha J, Estivill X
Missense mutation R1066C in the second transmembrane domain of CFTR causes a severe cystic fibrosis phenotype: study of 19 heterozygous and 2 homozygous patients.
Hum Mutat. 1997;10(5):387-92., [PMID:9375855]

Abstract [show]
We report the clinical features of 21 unrelated cystic fibrosis (CF) patients from Portugal and Spain, who carry the mutation R1066C in the CFTR gene. The current age of the patients was higher in the R1066C/any mutation group (P < 0.01), as compared to the deltaF508/deltaF508 group. Poor values for lung radiological involvement (Chrispin-Norman) and general status (Shwachman-Kulcycki) were observed in the R1066C/any mutation group (P < 0.005 and P < 0.0004). A slightly, but not significantly worse lung function was found in the R1066C/any mutation group when compared with the deltaF508/deltaF508 patients. No significant differences were detected regarding the age at diagnosis, sweat Cl-values, or percentiles of height and weight between the two groups. Neither were significant differences observed regarding sex, meconium ileus (4.7% vs. 11.1%), dehydration (10.5% vs. 14.7%), or pancreatic insufficiency (PI) (100% vs. 97.8%). The proportion of patients with lung colonization by bacterial pathogens was slightly, but not significantly higher in the R1066C/any mutation group (70.0%), as compared with the deltaF508/deltaF508 group (57.5%). Other clinical complications were significantly more frequent in the R1066C/any mutation patients(P < 0.02) than in the deltaF508/deltaF508 group. The two homozygous R1066C/R1066C patients died at the ages of 3 months and 7 years. The data presented in this study clearly demonstrate that the R1066C mutation is responsible for a severe phenotype similar to that observed in homozygous deltaF508 patients. The poor clinical scores and complications of patients with the R1066C mutation are probably related to their slightly longer survival.

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56 The current clinical data for missense mutations derived from a relatively large number of cases are limited to a few mutations: N1303K (Osborne et al., 1992; CF genotype-phenotype Consortium 1993), R117H (CF genotype-phenotype Consortium 1993), P205S (Chillón et al., 1993), A455E (Gan et al., 1995), L206W (Desgeorges et al., 1995), R334W (Estivill et al., 1995), and G85E (Vázquez et al., 1996). Login to comment

[hide] Sensitivity of the denaturing gradient gel electro... Hum Mutat. 1997;9(2):136-47. Macek M Jr, Mercier B, Mackova A, Miller PW, Hamosh A, Ferec C, Cutting GR
Sensitivity of the denaturing gradient gel electrophoresis technique in detection of known mutations and novel Asian mutations in the CFTR gene.
Hum Mutat. 1997;9(2):136-47., [PMID:9067754]

Abstract [show]
More than 500 mutations have been identified in the CFTR gene, making it an excellent system for testing mutation scanning techniques. To assess the sensitivity of denaturing gradient gel electrophoresis (DGGE), we collected a representative group of 202 CFTR mutations. All mutations analyzed were detected by scanning methods other than the DGGE approach evaluated in this study. DGGE analysis was performed on 24 of the 27 exons and their flanking splice site sequences. After optimization, 201 of the 202 control samples produced an altered migration pattern in the region in which an alteration occurred. The remaining sample was sequenced and found not to have the reported mutation. The ability of DGGE to identify novel mutations was evaluated in three Asian CF patients with four unknown CF alleles. Three novel Asian mutations were detected-K166E, L568X, and 3121-2 A-->G (in homozygosity)-accounting for all CF alleles. These results indicate that an optimized DGGE scanning strategy is highly sensitive and specific and can detect 100% of mutations.

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42 621 + 1 GÃT, R334W, R347P, A455E, aI507, aF508, 1717-1 GÃA, G542X, S549N, G551D, R553X, R560T, 3849 + 10kb CÃT, W1282X, and N1303K) was performed using the rapid multiplex reverse dot hybridization system, under conditions provided by Roche Molecular Systems (Alameda, CA) (Kawasaki et al., 1993; Welsh et al., 1995). Login to comment

[hide] Genotype-phenotype relationships in a cohort of ad... Eur Respir J. 1996 Nov;9(11):2207-14. Hubert D, Bienvenu T, Desmazes-Dufeu N, Fajac I, Lacronique J, Matran R, Kaplan JC, Dusser DJ
Genotype-phenotype relationships in a cohort of adult cystic fibrosis patients.
Eur Respir J. 1996 Nov;9(11):2207-14., [PMID:8947061]

Abstract [show]
In cystic fibrosis (CF), relationships between genotype and phenotype have been shown for pancreatic status but not for pulmonary disease. One hundred and ten adult CF patients were classified according to the expected effect of their mutations on cystic fibrosis transmembrane conductance regulator (CFTR) protein: Group 1 (n=48) included deltaF508 homozygotes; Group 2 (n=26), patients with two "severe" mutations and no expected CFTR production; Group 3 (n=17), patients with expected partly functional CFTR corresponding to at least one "mild" mutation; Group 4 (n=19), patients with no mutation identified or only one identified "severe" mutation. As compared to Groups 1 and 2: patients from Groups 3 and 4 had higher arterial oxygen tension (Pa,O2) (9.5+/-1.9 and 9.9+/-1.5 vs 8.8+/-1.5 and 8.3+/-1.7 kPa, respectively p<0.02); and a slower decline in their pulmonary function, estimated by the mean annual loss in forced vital capacity (FVC) (1.2+/-1.0 and 1.5+/-1.1 vs 2.0+/-0.9 and 2.2+/-1.0%, respectively; p<0.01) and in forced expiratory volume in one second (FEV1) (1.7+/-1.1 and 1.9+/-1.3 vs 2.6+/-1.0 and 2.8+/-1.0%, respectively; p<0.005). They had fewer episodes of colonization of the airways by Pseudomonas aeruginosa, and colonization occurred at a more advanced age (median age 25 and 19 vs 15 and 17 yrs, respectively; p<0.01) and required fewer intravenous antibiotic courses (p<0.01). Pancreatic insufficiency was less frequent in Groups 3 (23%) and 4 (63%) than in Groups 1 (100%) and 2 (96%). This study suggests that the phenotype of adult cystic fibrosis patients, including the severity of the lung disease, is related to the severity of the cystic fibrosis transmembrane conductance regulator mutations.

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22 Concerning the relationship between the severity of pulmonary involvement and other mutations than ∆F508, a mild pulmonary disease was described in two sisters homozygous for the G551S mutation [13], and in compound heterozygotes for the missense mutation A455E, a mutation commonly found in The Netherlands [14]. Login to comment
112 In the studies by GAN et al. [14], and STRONG et al. [13] patients with the A455E mutation or with the G551S mutation, respectively, who would be classified as Group 3 in the present study, had mild pulmonary disease. Login to comment

[hide] Effect of cystic fibrosis-associated mutations in ... J Biol Chem. 1996 Aug 30;271(35):21279-84. Cotten JF, Ostedgaard LS, Carson MR, Welsh MJ
Effect of cystic fibrosis-associated mutations in the fourth intracellular loop of cystic fibrosis transmembrane conductance regulator.
J Biol Chem. 1996 Aug 30;271(35):21279-84., [PMID:8702904]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) contains multiple membrane spanning sequences that form a Cl- channel pore and cytosolic domains that control the opening and closing of the channel. The fourth intracellular loop (ICL4), which connects the tenth and eleventh transmembrane spans, has a primary sequence that is highly conserved across species, is the site of a preserved sequence motif in the ABC transporter family, and contains a relatively large number of missense mutations associated with cystic fibrosis (CF). To investigate the role of ICL4 in CFTR function and to learn how CF mutations in this region disrupt function, we studied several CF-associated ICL4 mutants. We found that most ICL4 mutants disrupted the biosynthetic processing of CFTR, although not as severely as the most common DeltaF508 mutation. The mutations had no discernible effect on the channel's pore properties; but some altered gating behavior, the response to increasing concentrations of ATP, and stimulation in response to pyrophosphate. These effects on activity were similar to those observed with mutations in the nucleotide-binding domains, suggesting that ICL4 might help couple activity of the nucleotide-binding domains to gating of the Cl- channel pore. The data also explain how these mutations cause a loss of CFTR function and suggest that some patients with mutations in ICL4 may have a milder clinical phenotype because they retain partial activity of CFTR at the cell membrane.

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222 For example, H1085R is misprocessed like ⌬F508, yet it is reported to occur in a patient with a pancreatic sufficient phenotype. Login to comment
223 Conversely, our data with the mutants R1066L, R1066H, and A1067T are similar to that obtained with the "mild" mutants A455E and P574H (10) in that they retained partial processing and function. Login to comment

[hide] Heterogeneity of phenotype in two cystic fibrosis ... J Med Genet. 1996 Aug;33(8):711-3. Parad RB
Heterogeneity of phenotype in two cystic fibrosis patients homozygous for the CFTR exon 11 mutation G551D.
J Med Genet. 1996 Aug;33(8):711-3., [PMID:8863168]

Abstract [show]
In the heterozygous state, the cystic fibrosis transmembrane conductance regulator (CFTR) exon 11 mutation G551D has been described as "severe," causing pancreatic insufficiency. Two cystic fibrosis (CF) patients homozygous for this mutation showed a mild rather than severe pancreatic phenotype and a variable pulmonary phenotype.

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59 Consistent pulmo- boplastin nary phenotype has only been suggested with were nor- two mutations, RI 17H and A455E.9 10 CF, and G551D has been characterised as a class III mutation8 through its presumed impact on ATP binding." Login to comment

[hide] A mild variant of cystic fibrosis. Thorax. 1996 Aug;51 Suppl 2:S51-4. Alton EW
A mild variant of cystic fibrosis.
Thorax. 1996 Aug;51 Suppl 2:S51-4., [PMID:8869353]

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80 Novel findings of the paper by Gan et al The key finding of the paper by Gan et all is the identification of a mutation, A455E, that does appear to correlate with better lung prognosis. Login to comment
82 Lung function was significantly higher in age and sex matched patients than in AF508 homozygotes, fewer patients were colonised with Pseudomonas, and disease was diagnosed at a later age in the subjects with A455E mutation. Login to comment
92 Secondly, from a mechanistic point of view it will be important to understand why the A455E mutation differs from others in predicting a favourable outcome. Login to comment
95 One final consideration relates to the level of chloride secretion present in patients with the A455E mutation, which has been shown to allow residual secretion of chloride. Login to comment
100 A455E may produce a small increase in function above a critical level, resulting, in turn, in a disproportionately large increase in function sufficient to influence lung disease. Login to comment
101 Finally, it is worth noting that, given the relative rarity of some mutations, A455E may not turn out to be the only mutation associated with an improved respiratory prognosis. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... Am J Hum Genet. 1996 Jul;59(1):45-51. Miller PW, Hamosh A, Macek M Jr, Greenberger PA, MacLean J, Walden SM, Slavin RG, Cutting GR
Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in allergic bronchopulmonary aspergillosis.
Am J Hum Genet. 1996 Jul;59(1):45-51., [PMID:8659542]

Abstract [show]
The etiology of allergic bronchopulmonary aspergillosis (ABPA) is not well understood. A clinical phenotype resembling the pulmonary disease seen in cystic fibrosis (CF) patients can occur in some individuals with ABPA. Reports of familial occurrence of ABPA and increased incidence in CF patients suggest a possible genetic basis for the disease. To test this possibility, the entire coding region of the cystic fibrosis transmembrane regulator (CFTR) gene was analyzed in 11 individuals who met strict criteria for the diagnosis of ABPA and had normal sweat electrolytes (< or = 40 mmol/liter). One patient carried two CF mutations (deltaF508/R347H), and five were found to carry one CF mutation (four deltaF508; one R117H). The frequency of the deltaF508 mutation in patients with ABPA was significantly higher than in 53 Caucasian patients with chronic bronchitis (P < .0003) and the general population (P < .003). These results suggest that CFTR plays an etiologic role in a subset of ABPA patients.

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63 DNA samples from ABPA patients were screened for nine additional mutations associated with pancreatic sufficient and atypical CF: R117H (ASO), R347P (NcoI digest) and R347H (HhaI digest), R334W (MspI digest), A455E (ASO and BamHI digest), G551S (ASO) (Strong et al. 1991), 2789+5G-*A (ASO), D1152H (ASO) (Tsui 1992), and 3849+10kbC-*T (ASO and HphI digest) (Highsmith et al. 1994). Login to comment

[hide] Contribution of proline residues in the membrane-s... J Biol Chem. 1996 Jun 21;271(25):14995-5001. Sheppard DN, Travis SM, Ishihara H, Welsh MJ
Contribution of proline residues in the membrane-spanning domains of cystic fibrosis transmembrane conductance regulator to chloride channel function.
J Biol Chem. 1996 Jun 21;271(25):14995-5001., [PMID:8663008]

Abstract [show]
Proline residues located in membrane-spanning domains of transport proteins are thought to play an important structural role. In the cystic fibrosis transmembrane conductance regulator (CFTR), the predicted transmembrane segments contain four prolines: Pro99, Pro205, Pro324, and Pro1021. These residues are conserved across species, and mutations of two (P99L and P205S) are associated with cystic fibrosis. To evaluate the contribution of these prolines to CFTR Cl- channel function, we mutated each residue individually to either alanine or glycine or mutated all four simultaneously to alanine (P-Quad-A). We also constructed the two cystic fibrosis-associated mutations. cAMP agonists stimulated whole cell Cl- currents in HeLa cells expressing the individual constructs that resembled those produced by wild-type CFTR. However, the amount of current was decreased in the rank order: wild-type CFTR = Pro324 > Pro1021 > Pro99 >/= Pro205 mutants. The anion selectivity sequence of the mutants (Br- >/= Cl- > I-) resembled wild-type except for P99L (Br- >/= Cl- = I-). Although the Pro99, Pro324, and Pro1021 mutants produced mature protein, the amount of mature protein was much reduced with the Pro205 mutants, and the P-Quad-A made none. Because the Pro99 constructs produced mature protein but had altered whole cell currents, we investigated their single-channel properties. Mutant channels were regulated like wild-type CFTR; however, single-channel conductance was decreased in the rank order: wild-type CFTR >/= P99G > P99L >/= P99A. These results suggest that proline residues in the transmembrane segments are important for CFTR function, Pro205 is critical for correct protein processing, and Pro99 may contribute either directly or indirectly to the Cl- channel pore.

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192 In this regard they are similar to the CF mutations A455E and P574H that disrupt processing but generate channels that retain significant activity (23). Login to comment
217 The mechanism of dysfunction of P205S resembles that of the nucleotide-binding domain 1 pancreatic sufficiency mutants A455E and P574H, which are misprocessed (23). Login to comment
198 In this regard they are similar to the CF mutations A455E and P574H that disrupt processing but generate channels that retain significant activity (23). Login to comment
225 The mechanism of dysfunction of P205S resembles that of the nucleotide-binding domain 1 pancreatic sufficiency mutants A455E and P574H, which are misprocessed (23). Login to comment

[hide] Survey of cystic fibrosis transmembrane conductanc... Dig Dis Sci. 1996 Mar;41(3):540-2. McGill JM, Williams DM, Hunt CM
Survey of cystic fibrosis transmembrane conductance regulator genotypes in primary sclerosing cholangitis.
Dig Dis Sci. 1996 Mar;41(3):540-2., [PMID:8617131]

Abstract [show]
A variety of cholestatic liver diseases appear to primarily affect the biliary epithelium, including cystic fibrosis (CF). CF results from a defect in the chloride channel protein, cystic fibrosis transmembrane conductance regulator (CFTR). Although the majority of CF patients have a genomic deletion in deltaF508, other mutations of CFTR may result in less severe clinical presentations and outcomes. Recently, CFTR has been shown to be involved in secretin-stimulated choleresis in intrahepatic bile duct epithelial cells. Cholestasis in cystic fibrosis appears to result from defective chloride transport across the biliary epithelium and is the only cholestatic disease of bile ducts for which a cellular defect has been identified. Primary sclerosing cholangitis (PSC) is a cholestatic disease with histological and cholangiographic features similar to CF. The purpose of this pilot study was to explore whether there is an increased prevalence of CFTR mutations. Two patients exhibited mutations in one allele, yielding a carrier rate of 10.6%, not statistically different from the general U.S. population carrier rate of 4%.

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33 In total, 32 mutations were evaluated, which represent 90% of the most common mutations (t4): AF508 G542X G551D W1282X 3905insT NI303K 3849+ 10kbC--~T R553X 621+ IG--*T 1717- IG--,A lt)78delT 2789+5G---~A 3849+4A--~G 711+ IG---oT R1162X 1898+IG----~A R117H 3659delC G85E 2184delA A1507 R347P Y1092X R560T A455E R334W Y122X S549R(T---~G) Q493X V520F $549N R347H Patient Selection. Login to comment

[hide] Haplotype analysis of 94 cystic fibrosis mutations... Hum Mutat. 1996;8(2):149-59. Morral N, Dork T, Llevadot R, Dziadek V, Mercier B, Ferec C, Costes B, Girodon E, Zielenski J, Tsui LC, Tummler B, Estivill X
Haplotype analysis of 94 cystic fibrosis mutations with seven polymorphic CFTR DNA markers.
Hum Mutat. 1996;8(2):149-59., [PMID:8844213]

Abstract [show]
We have analyzed 416 normal and 467 chromosomes carrying 94 different cystic fibrosis (CF) mutations with polymorphic genetic markers J44, IVS6aGATT, IVS8CA, T854, IVS17BTA, IVS17BCA, and TUB20. The number of mutations found with each haplotype is proportional to its frequency among normal chromosomes, suggesting that there is no preferential haplotype in which mutations arise and thus excluding possible selection for specific haplotypes. While many common mutations in the worldwide CF population showed absence of haplotype variation, indicating their recent origins, some mutations were associated with more than one haplotype. The most common CF mutations, delta F508, G542X, and N1303K, showed the highest number of slippage events at microsatellites, suggesting that they are the most ancient CF mutations. Recurrence was probably the case for 9 CF mutations (R117H, H199Y, R347YH, R347P, L558S, 2184insA, 3272-26A-->G, R1162X, and 3849 + 10kbC-->T). This analysis of 94 CF mutations should facilitate mutation screening and provides useful data for studies on population genetics of CF.

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106 (1992) Dork et al. (1994a) Malone et al. (personal communication) Claustreset al. (1992) Ferec et al. (1992) Fanen et al. (1992) lvaschenko et al. (1991) T. Dork (personal communication) Dean et al. (1990) Dork et al. (1994a) Ferec et al. (1992) Bozon et al. (1994) Costes et al. (personal communication) Fanen et al. (1992) Audrezet et al. (personal communication) Zielenski et al. (1991a) Zielenski et al. (1991a) Granell et al. (1992) Highsmith et al. (1990) Mercier et al. (1993b) Vidaud et al. (1990) Fanen et al. (1992) Fanen et al. (1992) Dork et al. (1994b) (continued) HAPLOTYPESFOR 94 CF MUTATIONS TABLE2. CFTR HaplotvpesforDiallelic and Multiallelic DNA Markers for 94 CF Mutations"(Continued) ~~ ~ J44-GAIT- 8CA-17BTA- No. of TSU-TUB20 17BCA Mutation chromosomes % Normal Laboratory Reference 1-6-1-2 (9.1%) 1-6-2-2 (8.9%) 1-7-1-2 (3.4%) 1-7-2-2 (2.6%) 2-7-1-1 (1.2%) 2-7-2-2 (0.7%) 17-7-16 16-7-18 16-7-17 15-7-17 24-31-13 23-52-13 23-34-13 23-33-14 23-33-13 23-32-13 23-31-13 23-30-13 23-21-19 23-18-13 22-35-13 22-31-13 22-30-13 21-31-13 19-33-13 18-45-13 18-37-13 18-35-13 17-57-11 17-55-13 17-55-11 17-54-11 17-53-11 17-52-11 17-51-11 17-33-13 16-46-13 16-45-13 16-44-13 16-42-13 16-35-13 16-30-13 16-30-13 16-7-17 16-21-19 L107% L1077P 24ldelAT L719X A1507 3849+10kbC-T 2184insA 2991de132 G551D 1154insTC V520F R560T 4114ATA+lT 3667de14 435insA Q414X C225R Q39X N1303K R1162X H199Y G542X G542X w1204x R347H G542X AF50gb N1303K 2143delT 3849f 10kbC-T N1303K 681delC R347H A455E N1303K A120T 621+1 h T 574delA 1221delCT F311L R560K R553X R533X R553X Q552X R553X Q552X R116W R553X 1898+5 h T 3272-26A-G 1717-1hA 1342-2A-C A1507 2869insG 2869insG E92X 4374+1 h T 2183AA-G R117H 1609delCA I336K W1063X 1 1 1 1 6 1 3 1 1 22 17 1 1 1 1 1 1 1 1 1 1 1 1 1 17 1 1 4 157 7 1 2 2 1 1 2 2 1 9 1 1 1 1 1 1 6 1 1 1 2 1 3 2 1 3 1 1 1 4 2 4 1 1 - - 10.33 1.45 - - 0.48 1.45 - 0.24 1.45 0.24 - - - - 0.24 0.48 - - - - - - 0.49 0.48 - 0.24 0.24 0.24 - - - - - 0.72 0.24 0.72 - t h fP h b.fb,fP h b,fp.t t h b.fb.fp,h,t b.fb.fp,h,t t t t h b h h fP h fP fb b fP b.fb,fP,h.t fP fb b,fP,t b.fb,fp,h,t b.fb,h h h h,t t fb t b b b.fb.t fP fb fb tb h fP h h t t b h t h b b h h b,fb,h fP.h b h fP fP Bozon et al. (1994) Fanen et al. (1992) Dork et al. (1994a) Kerem et al. (1990) Dork et al. (1994~) Cutting et al. (1990) Kerem et al. (1990) lannuui et d. Login to comment

[hide] Cystic fibrosis mutation detection by hybridizatio... Hum Mutat. 1996;7(3):244-55. Cronin MT, Fucini RV, Kim SM, Masino RS, Wespi RM, Miyada CG
Cystic fibrosis mutation detection by hybridization to light-generated DNA probe arrays.
Hum Mutat. 1996;7(3):244-55., [PMID:8829658]

Abstract [show]
We have combined photochemistry and photolithography with solid-phase DNA synthesis chemistry to form a new technology that makes high density oligonucleotide probe array synthesis possible. Hybridization to these two-dimensional arrays containing hundreds or thousands of oligonucleotide probes provides a powerful DNA sequence analysis tool. Two types of light-generated DNA probe arrays have been used to test for a variety of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. One array, made up of 428 probes, was designed to scan through the length of CFTR exon 11 and identify differences from the wild type reference sequence. The second type of array contained 1480 probes chosen to detect known deletions, insertions, or base substitution mutations. The validity of the probe arrays was established by hybridizing them with fluorescently labeled control oligonucleotide targets. Characterized mutant CFTR genomic DNA samples were then used to further test probe array hybridization specificity. Finally, ten unknown patient samples were genotyped using the CFTR probe array assay. The genotype assignments were identical to those obtained by PCR product restriction fragment analysis. Our results show that light-generated DNA probe arrays are highly effective in analyzing complex mutation and polymorphism patterns in a relatively large gene such as CFTR.

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238 Cystic Fibrosis Mutation-Specific DNA Probe Array" Mutation Exon and column Tested Subarrayhow G85E R117H I148T 621 -+ l(G+T) 711 + 1(G+T) R334W R347H R347P 1078 delT A455E G480C Q493X A1507 F508C AF508 V520F G542X S549R(T-+ G) G551D Q552X R553X A559T R560T 1898 + l(G-,A) 2184 del A 2789 + 5(G+ A) R1066C L1077P Y1092X R1162X 3659 del C 1717-1(& A) 3272 - 26(A+ G) 3 4 4 in 4 in 5 7 7 7 7 9 10 10 10 10 10 10 in 10 11 11 11 11 11 11 11 in 12 13 in 14b in 17a 17b 17b 17b 19 19 * * * * * * * * * * * * * * * * * * * * * * * * * * * * 3849 + lOkb C-, T in 19 9,3 W1282X 20 994 3905insT 20 10.1 * N1303K 21 10,2 * * * "Row and column locations for each of the mutation specific,40 probe sets included in the specialized probe array design. Login to comment

[hide] Chloride channels and cystic fibrosis of the pancr... Biosci Rep. 1995 Dec;15(6):531-41. Gray MA, Winpenny JP, Verdon B, McAlroy H, Argent BE
Chloride channels and cystic fibrosis of the pancreas.
Biosci Rep. 1995 Dec;15(6):531-41., [PMID:9156582]

Abstract [show]
Cystic fibrosis (CF) affects approximately 1 in 2000 people making it one of the commonest fatal, inherited diseases in the Caucasian population. CF is caused by mutations in a cyclic AMP-regulated chloride channel known as CFTR, which is found on the apical plasma membrane of many exocrine epithelial cells. In the CF pancreas, dysfunction of the CFTR reduces the secretory activity of the tubular duct cells, which leads to blockage of the ductal system and eventual fibrosis of the whole gland. One possible approach to treating the disease would be to activate an alternative chloride channel capable of bypassing defective CFTR. A strong candidate for this is a chloride channel regulated by intracellular calcium, which has recently been shown to protect the pancreas in transgenic CF mice. Pharmacological intervention directed at activating this calcium-activated Cl- conductance might provide a possible therapy to treat the problems of pancreatic dysfunction in CF.

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117 The second group involves residues within NBD1 (A455E and P574H) which are located close to the walker A (residues 458-464) and B (residues 568-572) motifs, crucial for ATP binding. Login to comment
118 The second group involves residues within NBD1 (A455E and P574H) which are located close to the walker A (residues 458-464) and B (residues 568-572) motifs, crucial for ATP binding. Login to comment

[hide] Genetic and clinical features of patients with cys... Thorax. 1995 Dec;50(12):1301-4. Gan KH, Geus WP, Bakker W, Lamers CB, Heijerman HG
Genetic and clinical features of patients with cystic fibrosis diagnosed after the age of 16 years.
Thorax. 1995 Dec;50(12):1301-4., [PMID:8553305]

Abstract [show]
BACKGROUND: Cystic fibrosis is usually diagnosed in childhood, but a number of patients are not diagnosed until adulthood. The aim of this study was to investigate whether patients diagnosed at an older age had a different genetic constitution, manifestations of disease, and prognosis from those diagnosed at an early age. METHODS: Clinical data and results of lung function tests and DNA analysis of 143 adult patients with cystic fibrosis were entered into a computerised database. Patients diagnosed before their 16th birthday (early diagnosis, ED) were compared with those diagnosed at 16 years of age or older (late diagnosis, LD). RESULTS: Mean age of diagnosis of the ED group was 4.6 years compared with 27.7 years for the LD group. Mean (SD) percentage predicted pulmonary function was better for the LD group than for the ED group: forced expiratory volume in one second (FEV1) 72.5 (31.1)% and 52.0 (24.8)%, and forced vital capacity (FVC) 89.8 (25.7)% and 71.9 (23.0)%, respectively. Colonisation with Pseudomonas aeruginosa was present in 70% of the ED group and 24% of the LD group. In the ED group 81% had pancreatic insufficiency compared with only 12% of the LD group. None of the LD group was homozygous for delta F508 compared with 58% of the ED group. In the LD group 72% were compound AF508 heterozygotes and 28% had two non-delta F508 mutations. CONCLUSIONS: Among this group of 143 adult patients with cystic fibrosis late diagnosis is caused mainly by delayed expression and mild progression of clinical symptoms. Late diagnosis is associated with milder pulmonary disease, less pancreatic insufficiency, and different cystic fibrosis mutations. Since mortality in cystic fibrosis depends on the progression of pulmonary disease, patients with a late diagnosis have a better prognosis than those diagnosed early.

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41 DNA was analysed for the following mutations: E60X, R117H, A455E, AI507, AF508, G542X, S549N, G550X, G551D, R553X, R560T, R1162X, S1251N, W1282X, N1303K, 621 + 1G-+T, 1717-1G--+A. These mutations represent 80% ofthe expected cystic fibrosis mutations in The Netherlands. Login to comment
69 The A455E mutation was relatively frequent in the LD group. Login to comment
98 Most of those diagnosed at 16 years or older were pancreatic sufficient, which is closely related to the type of CFTR mutation.2829 The A455E mutation was frequently found among this group of patients and preliminary studies indicate that this mutation, known to be related to pancreatic sufficiency,29 may be associated with mild pulmonary disease.30 It seems that other CFTR mutations (some ofwhich are still unidentified) in patients diagnosed late are associated with pancreatic sufficiency and also with mild pulmonary disease. Login to comment

[hide] Correlation of sweat chloride concentration with c... J Pediatr. 1995 Nov;127(5):705-10. Wilschanski M, Zielenski J, Markiewicz D, Tsui LC, Corey M, Levison H, Durie PR
Correlation of sweat chloride concentration with classes of the cystic fibrosis transmembrane conductance regulator gene mutations.
J Pediatr. 1995 Nov;127(5):705-10., [PMID:7472820]

Abstract [show]
OBJECTIVE: To compare differences in epithelial chloride conductance according to class of mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. METHODS: We evaluated the relationship between the functional classes of CFTR mutations and chloride conductance using the first diagnostic sweat chloride concentration in a large cystic fibrosis (CF) population. RESULTS: There was no difference in sweat chloride value value between classes of CFTR mutations that produce no protein (class I), fail to reach the apical membrane because of defective processing (class II), or produce protein that fails to respond to cyclic adenosine monophosphate (class III). Those mutations that produce a cyclic adenosine monophosphate-responsive channel with reduced conductance (class IV) were associated with a significantly lower, intermediate sweat chloride value. However, patients with the mutations that cause reduced synthesis or partially defective processing of normal CFTR (class V) had sweat chloride concentrations similar to those in classes I to III. CONCLUSION: Studies of differences in chloride conductance between functional classes of CFTR mutations provide insight into phenotypic expression of the disease.

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13 Abnormal function of the channel results in aber- cAMP CF CFTR NBF PI PS RT-PCR Cyclicadenosinemonophosphate Cysticfibrosis Cysticfibrosistransmembraneconductance regulator Nucleotidebindingfold Pancreaticinsufficiency Pancreaticsufficiency Restrictiontransferasepolymerasechainreaction rant chloride conductance across the apical membrane of epithelial cells in a variety of organs.l-5 Approximately 70% of the CF chromosomes harbor a three base-pair deletionre- 705 0 Wilschanski et al. The Journal of Pediatrics November 1995 I II Ill IV V Normal Nonsense Missense G542X Missense Missense Missense A455E Frameshift AA deletion G551D R117H Alternative 394delTT AF508 splicing Splice junction 3849+10kbC~T 1717-1G~A (a) (b) (c) (d) (e) (f) Figure. Login to comment
43 Defined mutations (each mutation cited in references 8, 23, and 24; numerals in parentheses indicate number of patients): Nonsense mutations-----class I: Frameshift mutations---class I: Splice site mutations-class I: Missense mutations---class HI: Missense mutations---class IV: Partially defective processing---class V: Alternative spficing-----classV: R1162X (3), Y1092X (3), G542X (21), Q552X (2), Q493X (2), w1282x (2), E1104X (1), R553X (6), E585X (l), (all PI) 3659delC (5), 2184delA (4), 4010de14 (1), 556delA (1), 3002delG (1) 3905insT (1), 4016insT (3), 1154insTC (l), 441delA (1), 2184insA (2), 1078delT (1), 4326delTC (3) (all PI) I717-1G--~A (4), 621+lG--*T (10), 711+IG--~T (3), 875+1G-+C (2), 3120+IG-~A (1) (18 PI, 2 PS) G551D (25), N1303K (7), R560T (8), I148T (1), G85E (3), A559T (1), L1077P (2), T1234V (1), (47 PI, 1 PS) R117H (10), R347H (3), R347P (1), D614G (1), S1251N (2), (all PS) P574H (2), A455E (2), (all PS) 3272-26A-+G (4), 3849+10KbC---~T (2), 3120G-+A (1), (all PS) analysis, we further grouped the patients according to the molecular consequences conferred by the CFTR alleles. Login to comment
107 Electrophysiologic studies on the mild mutations A455E and P574H revealed that single-channel conductance was not different from the normal CFFR channel but that less protein reached the membrane. Login to comment
12 Abnormal function of the channel results in aber- cAMP CF CFTR NBF PI PS RT-PCR Cyclicadenosinemonophosphate Cysticfibrosis Cysticfibrosistransmembraneconductance regulator Nucleotidebindingfold Pancreaticinsufficiency Pancreaticsufficiency Restrictiontransferasepolymerasechainreaction rant chloride conductance across the apical membrane of epithelial cells in a variety of organs.l-5 Approximately 70% of the CF chromosomes harbor a three base-pair deletionre- 705 0 Wilschanski et al. The Journal of Pediatrics November 1995 I II Ill IV V Normal Nonsense Missense G542X Missense Missense Missense A455E Frameshift AA deletion G551D R117H Alternative 394delTT AF508 splicing Splice junction 3849+10kbC~T 1717-1G~A (a) (b) (c) (d) (e) (f) Figure. Login to comment

[hide] Screening Young syndrome patients for CFTR mutatio... Am J Respir Crit Care Med. 1995 Oct;152(4 Pt 1):1353-7. Friedman KJ, Teichtahl H, De Kretser DM, Temple-Smith P, Southwick GJ, Silverman LM, Highsmith WE Jr, Boucher RC, Knowles MR
Screening Young syndrome patients for CFTR mutations.
Am J Respir Crit Care Med. 1995 Oct;152(4 Pt 1):1353-7., [PMID:7551394]

Abstract [show]
Young syndrome is characterized by obstructive azoospermia associated with chronic sinobronchial disease of an infectious nature, but normal sweat-gland and pancreatic function as well as normal nasal potential differences. Congenital bilateral absence of the vas deferens (CBAVD) in some patients arises from mutations within the cystic fibrosis (CF) transmembrane regulator (CFTR) gene. Because of some similarities between Young syndrome, CF, and CBAVD, we evaluated 13 patients with Young syndrome, including screening for more than 30 different mutations within the CFTR gene. The mean age of the patients was 43 yr (range, 32 to 50 yr), and all were of northern European extraction. The sweat chloride concentration was normal in all patients (mean = 29 mEq/L; range, 8 to 43 mEq/L). Most had intermittent bronchial and sinus infections, but none was chronically colonized with Staphylococcus aureus or Pseudomonas aeruginosa. The FEV1 was normal or only mildly reduced in most patients (mean = 74%; range, 48 to 100% predicted). Of 26 Young syndrome chromosomes, we identified one with the recognized CF mutation delta F508. The incidence of CFTR mutations (1 in 26) did not differ significantly from the expected carrier frequency in this population. In summary, it is unlikely that the typical Young syndrome patient has a clinical disease associated with CFTR mutation on both alleles.

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78 Of the 13 Young syndrome patients, we identified one (Patient 5) who was het- CBAVD Dl152H D1270N G576A* R75Q* P67L Rl17H 3849 + 10 KB C > T G551S Rl17H Pancreatic Sufficient, Moderate Pulmonary Symptoms, Normal Sweat Chloride Concentrations Pancreatic Sufficient, Moderate Pulmonary Symptoms R347P 2789 + 5 G > A R334W G85E R347H R347L Rl17H G91R A455E S945L Y563N Q1291H R297Q R352Q L1065P 3850-3 T > G F1286S 3849 + 10 KB C > T TABLE 1 CFTR MUTATION SCREENING PANEL Severe M508 G551D R553X N1303K W1282X G542X 1717-1 G > A ~1507 R560T 3659deiC 621 + 1 G > T S549N TABLE 2 CLINICAL FEATURES OF YOUNG SYNDROME PATIENTS Patient Age Sweat CI- FEV, Paranasal Sputum No. Login to comment

[hide] Two cystic fibrosis transmembrane conductance regu... Proc Natl Acad Sci U S A. 1995 Jul 18;92(15):6832-6. Fulmer SB, Schwiebert EM, Morales MM, Guggino WB, Cutting GR
Two cystic fibrosis transmembrane conductance regulator mutations have different effects on both pulmonary phenotype and regulation of outwardly rectified chloride currents.
Proc Natl Acad Sci U S A. 1995 Jul 18;92(15):6832-6., [PMID:7542778]

Abstract [show]
Cystic fibrosis (CF), a disorder of electrolyte transport manifest in the lungs, pancreas, sweat duct, and vas deferens, is caused by mutations in the CF transmembrane conductance regulator (CFTR). The CFTR protein has been shown to function as a cAMP-activated chloride channel and also regulates a separate protein, the outwardly rectifying chloride channel (ORCC). To determine the consequence of disease-producing mutations upon these functions, mutant CFTR was transiently expressed in Xenopus oocytes and in human airway epithelial cells lacking functional CFTR. Both G551D, a mutation that causes severe lung disease, and A455E, a mutation associated with mild lung disease, altered but did not abolish CFTR's function as a chloride channel in Xenopus oocytes. Airway epithelial cells transfected with CFTR bearing either A455E or G551D had levels of chloride conductance significantly greater than those of mock-transfected and lower than those of wild-type CFTR-transfected cells, as measured by chloride efflux. A combination of channel blockers and analysis of current-voltage relationships were used to dissect the contribution of CFTR and the ORCC to whole cell currents of transfected cells. While CFTR bearing either mutation could function as a chloride channel, only CFTR bearing A455E retained the function of regulating the ORCC. These results indicate that CF mutations can affect CFTR functions differently and suggest that severity of pulmonary disease may be more closely associated with the regulatory rather than chloride channel function of CFTR.

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4 Both G551D, a mutation that causes severe lung disease, and A455E, a mutation associated with mild lung disease, altered but did not abolish CFTR's function as a chloride channel in Xenopus oocytes. Login to comment
5 Airway epithelial cells transfected with CFTR bearing either A455E or G551D had levels of chloride conductance significantly greater than those of mock-transfected and lower than those of wild-type CFTR-transfected cells, as measured by chloride efflux. Login to comment
7 While CFTrR bearing either mutation could function as a chloride channel, only CFTR bearing A455E retained the function of regulating the ORCC. Login to comment
27 To determine whether disease-associated mutations affect the regulatory function of CFTR, the functional consequences of two mutations, A455E and G551D, were studied. Login to comment
29 When G551D/ AF508 compound heterozygotes were compared with sex- and age-matched AF508 homozygotes, there was no difference in severity of pancreatic or pulmonary disease (15). Login to comment
30 However, comparison of A455E/AF508 compound heterozygotes with AF508 homozygotes revealed significantly better lung function in the heterozygotes, as measured by mean yearly decline in the volume of air forcibly expired in 1 s [forced expiratory volume in 1 s (FEV1); P < 0.0005] (16, 17). Login to comment
31 Since the ORCC appears to be regulated by CFTR in respiratory epithelium, we studied the function of CFTR bearing either A455E or G551D in a Abbreviations: CF, cystic fibrosis; CFTR, CF transmembrane conductance regulator; ORCC, outwardly rectifying chloride channel; CPT-cAMP, 8-(4-chlorophenylthio)-cAMP; DIDS, 4,4'-diisothiocyanostil- bene-2,2'-disulfonic acid; IBMX, 3-isobutyl-1-methylxanthine; RSV, Rous sarcoma virus. Login to comment
33 Our data suggest that CFTR bearing A455E can function as a cAMP-regulated chloride channel and also maintains its capacity to regulate the ORCC. Login to comment
37 The A455E mutation was created using the oligonucleotide 5'- GTTGTTGGAGGTTGCTGG-3'. Login to comment
46 The mutations, A455E and G551D, were created in pBQ4.7 (a generous gift from J. Rommens and L.-C. Tsui; The Hospital for Sick Children, Toronto) then shuttled to the pAvS6.CFTR or pRSV-CFTR by using Kpn2I and Hpa I (BRL) restriction sites common to all vectors. Login to comment
69 As seen in Fig. 1, oocytes injected with wild-type, G551D-, or A455E-CFTR generated cAMP-stimulated Cl- currents significantly greater than basal level. Login to comment
72 The currents in A455E-CFTR-injected oocytes were about 67% of wild-type, suggesting that A455E-CFTR forms a cAMP-activated chloride channel in Xenopus oocytes. Login to comment
77 |==I Control ~~ Fornkon +IBMX * Control Wild-type G551D A455E FIG. 1. Bar graph summary of Cl- currents (Icl) measured at a clamped voltage of -90 mV before and after stimulation with forskolin (10 ,uM) and IBMX (1 mM) for Xenopus oocytes injected with water (Control; n = 9), wild-type CFTR cRNA (n = 16), G551D-CFTR cRNA (n = 6), or A455E-CFTR cRNA (n = 6). Login to comment
86 IB3-1 cells were transfected with the RSV vector containing wild-type CFTR, G551D-CFTR, or A455E-CFTR. Login to comment
92 IB3-1 cells g+ DIDS were transiently transfected with + Glyb wild-type CFTR (A), G551D-CFTR (B), or A455E-CFTR (C). Login to comment
97 Fifteen seconds after addition of CPT-cAMP, efflux rates from cells transfected with wild-type CFTR (41.7% ± 6.0% of Cl- lost per min; n = 12) or G551D-CFTR (40.8% ± 4.5%; n = 6) were significantly greater (P < 0.05) than that of mock-transfected cells (28.9% ± 4.4%; n = 12). Login to comment
98 Thirty seconds after CPT-cAMP addition, efflux rates from cells transfected with wild-type CFTR (47.8% ± 12.3%; n = 12) and A455E-CFTR (38.1% ± 6.5%; n = 6) were significantly greater (P < 0.05) than that of mock-transfected cells (26.4% ± 5.5%; n = 12). Login to comment
99 These results indicate that both A455E-CFTR and G551D-CFTR produce cAMP-mediated chloride secretion in IB3-1 cells. Login to comment
115 A455E-CFTR-expressing cells showed results similar to wild type, although the induced currents were lower (Fig. 2C). Login to comment
116 The I-Vrelationship for A455E-CFTR-expressing cells was slightly outwardly rectified. Login to comment
121 The similarity between the currents of wild-type CFTR and A455E-CFTR and their differences from G551D-CFTR currents were evident from examination ofthe outwardly rectified versus linear current component for each (Fig. 3). Login to comment
123 Wild-type CFTR-expressing and A455E-CFTR-expressing cells also showed a significant increase (P < 0.05) in outwardly rectified current. Login to comment
124 Taken together, these results indicated that although an outwardly rectified, DIDS-sensitive current contributed to the whole cell currents in wild-type CFTR-expressing and A455E-CFTR-expressing cells, it did not con- 0 c) .., 500 A 400 300 200 100 0 500 ( < 400 0. Login to comment
129 (C) G551D-CFTR (Nonexp, n = 12; Exp, n = 5). Login to comment
130 (D) A455E-CFTR (Nonexp, n = 15; Exp, n = 6). Login to comment
150 On the other hand, DIDS, a compound that blocks the ORCC, inhibited a significant fraction of wild-type CFTR currents but had no effect on G551D-CFTR currents. Login to comment
151 The A455E mutation also alters CFTR function. Login to comment
153 Therefore, it is difficult to predict the molecular consequences of the A455E mutation. Login to comment
157 They found that A455E alters the processing of CFTR, and, when properly processed, A455E-CFTR functions as a chloride channel (30). Login to comment
158 In this study, A455E-CFTR-generated currents were about the same fraction (about two-thirds) of wild-type CFTR in both mammalian and Xenopus systems. Login to comment
159 This result indicates that if A455E causes a processing defect, it is not ameliorated by expression in Xenopus oocytes at 25°C. A455E-CFTR expressed in IB3-1 cells has both chloride channel and regulatory functions intact. Login to comment
160 Therefore, our data are consistent with the concept that A455E could cause a processing defect, which leads to decreased amounts of A455E-CFTR at the cell surface. Login to comment
161 A455E-CFTR that reaches the cell membrane appears to function similar to wild-type CFTR. Login to comment
163 Patients carrying A455E have been shown to be pancreatic sufficient, a situation that occurs with other partially functional mutants (31), but A455E also appears to be associated with mild lung disease (16, 17). Login to comment
164 This study demonstrates that A455E does not abolish the function of CFTR as a regulator, in particular as a regulator of the ORCC. Login to comment
167 The authors thank Dr. I. McIntosh for creating the G551D and A455E mutations, S. Allen for excellent technical assistance, J. Staton for secretarial assistance, and Genetic Therapy, Inc., for the gift of the pAvS6 vectors. Login to comment
26 To determine whether disease-associated mutations affect the regulatory function of CFTR, the functional consequences of two mutations, A455E and G551D, were studied. Login to comment
32 Our data suggest that CFTR bearing A455E can function as a cAMP-regulated chloride channel and also maintains its capacity to regulate the ORCC. Login to comment
36 The A455E mutation was created using the oligonucleotide 5'- GTTGTTGGAGGTTGCTGG-3'. Login to comment
45 The mutations, A455E and G551D, were created in pBQ4.7 (a generous gift from J. Rommens and L.-C. Tsui; The Hospital for Sick Children, Toronto) then shuttled to the pAvS6.CFTR or pRSV-CFTR by using Kpn2I and Hpa I (BRL) restriction sites common to all vectors. Login to comment
68 As seen in Fig. 1, oocytes injected with wild-type, G551D-, or A455E-CFTR generated cAMP-stimulated Cl-currents significantly greater than basal level. Login to comment
71 The currents in A455E-CFTR-injected oocytes were about 67% of wild-type, suggesting that A455E-CFTR forms a cAMP-activated chloride channel in Xenopus oocytes. Login to comment
76 |== I Control ~~ Fornkon +IBMX * Control Wild-type G551D A455E FIG. 1. Bar graph summary of Cl-currents (Icl) measured at a clamped voltage of -90 mV before and after stimulation with forskolin (10 ,uM) and IBMX (1 mM) for Xenopus oocytes injected with water (Control; n = 9), wild-type CFTR cRNA (n = 16), G551D-CFTR cRNA (n = 6), or A455E-CFTR cRNA (n = 6). Login to comment
85 IB3-1 cells were transfected with the RSV vector containing wild-type CFTR, G551D-CFTR, or A455E-CFTR. Login to comment
91 IB3-1 cells g+ DIDS were transiently transfected with + Glyb wild-type CFTR (A), G551D-CFTR (B), or A455E-CFTR (C). Login to comment
114 A455E-CFTR-expressing cells showed results similar to wild type, although the induced currents were lower (Fig. 2C). Login to comment
120 The similarity between the currents of wild-type CFTR and A455E-CFTR and their differences from G551D-CFTR currents were evident from examination ofthe outwardly rectified versus linear current component for each (Fig. 3). Login to comment
122 Wild-type CFTR-expressing and A455E-CFTR-expressing cells also showed a significant increase (P < 0.05) in outwardly rectified current. Login to comment
152 Therefore, it is difficult to predict the molecular consequences of the A455E mutation. Login to comment
156 They found that A455E alters the processing of CFTR, and, when properly processed, A455E-CFTR functions as a chloride channel (30). Login to comment
162 Patients carrying A455E have been shown to be pancreatic sufficient, a situation that occurs with other partially functional mutants (31), but A455E also appears to be associated with mild lung disease (16, 17). Login to comment
166 The authors thank Dr. I. McIntosh for creating the G551D and A455E mutations, S. Allen for excellent technical assistance, J. Staton for secretarial assistance, and Genetic Therapy, Inc., for the gift of the pAvS6 vectors. Login to comment

[hide] A cystic fibrosis mutation associated with mild lu... N Engl J Med. 1995 Jul 13;333(2):95-9. Gan KH, Veeze HJ, van den Ouweland AM, Halley DJ, Scheffer H, van der Hout A, Overbeek SE, de Jongste JC, Bakker W, Heijerman HG
A cystic fibrosis mutation associated with mild lung disease.
N Engl J Med. 1995 Jul 13;333(2):95-9., [PMID:7539891]

Abstract [show]
BACKGROUND: Cystic fibrosis is the most common lethal autosomal recessive disorder among whites. Among Dutch patients with cystic fibrosis, delta F508 is the most common mutation and A455E the second most common mutation of the cystic fibrosis transmembrane conductance regulator gene on chromosome 7. A455E is associated with preserved pancreatic function and residual secretion of chloride across membranes. We investigated whether it is also associated with less severe pulmonary disease in patients with cystic fibrosis. METHODS: A total of 33 patients with compound heterozygosity for the A455E mutation were matched according to age and sex with patients who were homozygous for the delta F508 mutation. The pairs were analyzed with respect to the following outcome variables: age at diagnosis, pulmonary-function values, and the frequency of pseudomonas colonization, pancreatic sufficiency, and diabetes mellitus. RESULTS: Cystic fibrosis was diagnosed at a later age in the patients with the A455E mutation than in the delta F508 homozygotes (mean age at diagnosis, 15.0 vs. 3.1 years; P < 0.001). Fewer patients with the A455E mutation had pancreatic insufficiency (21.2 percent vs. 93.9 percent, P < 0.001), and none had diabetes mellitus (0 percent vs. 27.3 percent, P = 0.004). Forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were significantly higher in the patients with the A455E mutation (mean FEV1, 73.9 percent of the predicted value vs. 54.3 percent of the predicted value; P = 0.002; mean FVC, 88.7 percent of the predicted value vs. 76.3 percent of the predicted value; P = 0.04). Fewer patients with the A455E mutation were colonized with Pseudomonas aeruginosa (33.3 percent vs. 60.6 percent, P = 0.02). CONCLUSIONS: A455E is a common mutation causing cystic fibrosis in the Netherlands. Although several mutations are known to be associated with less severe pancreatic disease, our findings demonstrate a correlation between the A455E mutation and mild pulmonary disease. Because mortality in this disease depends primarily on the progression of pulmonary disease, patients with the A455E mutation have a better prognosis than patients who are homozygous for the delta F508 mutation.

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29 Since the gene for cystic fibrosis was cloned, there have been several studies on associations between the genotype and the phenotype in cystic fibrosis.5-8 A number of mutations (R117H, R334W, R347P, A455E, and P574H) appear to be associated with pancreatic sufficiency9 and residual transmembrane transport of chloride.10,11 The most common mutation, ⌬F508, is associated with pancreatic insufficiency and severe pulmonary disease.5,6 There is great variation in the severity of lung disease, but until now no mutation associated with mild pulmonary disease has been found. Login to comment
30 Recently, we noted that a group of Dutch patients with cystic fibrosis who carried the A455E mutation had significantly better lung function than patients homozygous for the ⌬F508 mutation.12 An association between this mutation and exocrine pancreatic sufficiency has already been described.9,11 In addition, A455E appears to be associated with residual secretion of chloride in electrophysiologic studies of rectal-biopsy specimens.11 Among our patients the A455E mutation is relatively common and is associated with an older age at diagnosis.11,13 Because of the older age at diagnosis and the mutation-dependent residual chloride secretion associated with A455E, we hypothesized that the presence of this mutation could result in milder lung disease. Login to comment
34 Among the patients screened, 151 were found to be homozygous for the ⌬F508 mutation and 39 were found to have compound heterozygosity for the A455E mutation. Login to comment
35 In the A455E compound heterozygotes, the following mutations were found on the other allele: ⌬F508 (27 patients), 1717-1G→A (4 patients), E60X (4 patients), G542X (2 patients), R553X (1 patient), and an unknown mutation (1 patient). Login to comment
37 The other mutations found in A455E heterozygotes are all associated with pancreatic insufficiency and have been classified as severe cystic fibrosis mutations,8 predicted to produce no functioning CFTR.14 Therefore, all patients with an A455E allele were analyzed together. Login to comment
38 One patient, whose genotype was A455E/ ⌬F508, has been described elsewhere.15 This patient died at the age of 71 and could not be matched with a ⌬F508 homozygote because of her advanced age. Login to comment
39 No other data on deceased A455E compound heterozygotes were available, and therefore no data on deceased patients were included in the analysis of matched pairs. Login to comment
41 Analysis for the ⌬F508 mutation was carried out by direct polyacrylamide-gel electrophoresis of the CFTR exon 10 product of the polymerase chain reaction16 or as part of a multiplex amplification refractory mutation system.17 For the analysis of the A455E mutation, a specific amplification refractory mutation system was developed (Scheffer H, et al.: unpublished data). Login to comment
43 For A455E compound heterozygotes, the place of birth was recorded, as were the birthplaces and family names of their parents and grandparents, as far as could be ascertained. Login to comment
51 Statistical Analysis Each of the patients with the A455E mutation was matched with the ⌬F508 homozygote closest in age, within two years, and of the same sex. Login to comment
52 The patient who died at the age of 71 and four other A455E compound heterozygotes (40, 43, 53, and 47 years old, with the first three having a genotype of A455E/1717-1G→A and the fourth a genotype of A455E/⌬F508) could not be matched within two years of age with a ⌬F508 homozygote and were excluded. Login to comment
61 As far as could be determined, the families of the A455E compound heterozygotes were not related, nor did they come from geographically isolated regions. Login to comment
63 At least four A455E heterozygotes were former cigarette smokers, whereas none of the ⌬F508 homozygotes had ever smoked. Login to comment
66 The patients with the A455E mutation had significantly better lung function than did the ⌬F508 homozygotes (mean FEV1, 73.9 percent of the predicted value vs. 54.3 percent of the predicted value; Pϭ0.002). Login to comment
67 The mean FVC was 88.7 percent for A455E compound heterozygotes and 76.3 percent for ⌬F508 homozygotes (Pϭ0.04). Login to comment
69 †The following genotypes were identified: A455E/⌬F508 (25 patients), A455E/E60X (4), A455E/G542X (2), A455E/R553X (1), and A455E/1717-1G→A (1). Login to comment
75 Characteristics of Pairs of ⌬F508 Homozygotes and A455E Compound Heterozygotes Matched According to Sex and Age. Login to comment
77 OF PAIRS ⌬F508 HOMOZYGOTES A455E COMPOUND HETEROZYGOTES† P VALUE Sex - no. Login to comment
81 (%) 33 9 (27.3) 0 0.004¶ Weight - (percentile)ʈ 33 61.0Ϯ29.4 53.4Ϯ30.3 NS Height - (percentile) Men 16 21.4Ϯ25.0 42.0Ϯ27.6 0.03‡ Women 17 38.1Ϯ28.2 38.7Ϯ29.4 NS less prevalent in patients with the A455E mutation, and diabetes mellitus was absent in this group (Pϭ0.004). Login to comment
83 The men with the A455E mutation, but not the women, were significantly taller than matched ⌬F508 homozygotes. Login to comment
85 The regression line had a slope of -0.0089 for A455E compound heterozygotes and a significantly steeper slope of -0.0178 for ⌬F508 homozygotes (Pϭ0.02). Login to comment
87 DISCUSSION The results of this study show that there is a relation between the presence of the A455E mutation and milder lung disease in patients with cystic fibrosis. Login to comment
88 Although the A455E mutation is known to be associated with pancreatic sufficiency,9 the association between A455E or any other cystic fibrosis mutation and milder lung disease has apparently not been found before. Login to comment
90 To overcome this problem, the Cystic Fibrosis Genotype-Phenotype Consortium initiated a large multicenter study that included 798 patients with cystic fibrosis.8 Of the eight mutations studied, none were associated with mild lung disease (A455E was not included). Login to comment
91 R117H, a mutation associated with residual transmembrane chloride transport,10 was also associated with an older age at diagnosis and with pancreatic sufficiency, but not with better lung function. Login to comment
92 The severity of disease in cystic fibrosis is determined by the mutation resulting in the least severe disease.9 All the A455E compound heterozygotes included in our study had a mutation on their other allele that was associated with severe disease. Login to comment
93 Mild symptoms in these patients are therefore most likely associated with the presence of the A455E mutation. Login to comment
97 FEV1 in 34 A455E Compound Heterozygotes and 130 ⌬F508 Homozygotes, According to Age. Login to comment
98 Solid squares represent patients included in the matched-pairs analysis; 4 A455E compound heterozygotes and 21 ⌬F508 homozygotes were not included because they were too young for pulmonary-function testing. Login to comment
100 The regression line had a slope of -0.0089 for A455E compound heterozygotes and -0.0178 for ⌬F508 homozygotes (Pϭ0.02). Login to comment
101 *Includes 31 A455E compound heterozygotes from the present study. Login to comment
105 Frequency of ⌬F508 and A455E Mutations in Various Countries. Login to comment
107 OF CHROMOSOMES SCREENED ⌬F508 A455E % Present study The Netherlands 556 73 7.0 Cystic Fibrosis Genetic Analysis Consortium33 The Netherlands* 1043 77.1 3.0 Lindner et al.34 Southwestern Germany 220 67 0 Cuppens et al.35 Belgium 200 72.5 1.0 Super and Schwarz36 Northwestern England 1008 82 0 Shrimpton et al.37 Scotland 506 72.3 0.5 Claustres et al.38 Southern France 262 63 0 Cutting et al.39 Baltimore 163 76.1 0.6 Cutting et al.,39 Zielenski et al.40 Toronto 1030 68.4 0.2 Rozen et al.31 Quebec 84 71 1 Rozen et al.31 Saguenay-Lac St. Jean, Quebec 182 58 8 Cutting et al.39 United States† 43 37 0 Cutting et al.39 Israel‡ 94 30 0 FEV1(%ofpredictedvalue) 140 120 100 80 60 40 20 0 706050403020100 A455E Compound Heterozygotes Age (years) FEV1(%ofpredictedvalue) 140 120 100 80 60 40 20 0 706050403020100 DF508 Homozygotes Age (years) Our results show that the type of mutation has a significant impact on pulmonary function in cystic fibrosis. Login to comment
108 Because of the relatively high frequency of the A455E mutation among our patients, we were able to include 33 patients, as compared with the 23 patients with the R117H mutation included in the consortium`s report.8 When sufficient numbers of patients are studied, it should be possible to show that other mutations associated with the preservation of pancreatic function and residual transmembrane chloride transport are also associated with milder pulmonary disease. Login to comment
109 A455E is a missense mutation that leads to a change from alanine to glutamic acid in amino acid residue 455 of the CFTR protein.27 CFTR is a chloride transporter driven by cAMP, and the A455E mutation is situated in the first nucleotide-binding fold, two residues removed from the so-called Walker-A motif, the proposed site of interaction with the phosphoryl moiety of the bound cAMP.28 The A455E mutation may interfere with the binding of cAMP to the CFTR protein. Login to comment
110 The CFTR protein coded for by the ⌬F508 mutation is subject to defective intracellular processing and does not reach the cell membrane, but is degraded intracellularly.29 The CFTR protein containing the A455E mutation may also be subject to this mechanism, but to a lesser degree.30 Unlike ⌬F508 homozygotes, patients with cystic fibrosis who have the A455E mutation have residual transmembrane chloride transport,11 a point that increases the likelihood that at least some functioning CFTR protein reaches the cell membrane. Login to comment
111 The A455E mutation was first found in patients from the Saguenay-Lac St. Jean region in northern Quebec.27,31 In this formerly isolated community, the incidence of cystic fibrosis and other inherited diseases is higher than normal.32 The A455E mutation is seldom found elsewhere in the world (Table 2),31,33-40 but it is relatively common in the Netherlands, where it is the second most common cystic fibrosis mutation (3.0 percent of all cystic fibrosis alleles).33 The two mutations that we studied, ⌬F508 and A455E, account for 80.1 percent of the mutations found in Dutch patients with cystic fibrosis. Login to comment
112 In our study the frequency of A455E was 7.0 percent, which may be related to the age distribution of our patients. Login to comment
113 In our patients, the presence of the A455E mutation was associated with the preservation of both endocrine and exocrine pancreatic function, less frequent colonization with P. aeruginosa, and mild lung disease. Login to comment
114 The regression line for FEV1 according to age was less steep in A455E compound heterozygotes than in ⌬F508 homozygotes, an indication that the progression of pulmonary disease is slower in patients with the A455E mutation. Login to comment
115 A455E is the first CFTR mutation for which an association with mild lung disease could be found. Login to comment
28 Since the gene for cystic fibrosis was cloned, there have been several studies on associations between the genotype and the phenotype in cystic fibrosis.5-8 A number of mutations (R117H, R334W, R347P , A455E, and P574H) appear to be associated with pancreatic sufficiency9 and residual transmembrane transport of chloride.10,11 The most common mutation, F508, is associated with pancreatic insufficiency and severe pulmonary disease.5,6 There is great variation in the severity of lung disease, but until now no mutation associated with mild pulmonary disease has been found. Login to comment
33 Among the patients screened, 151 were found to be homozygous for the F508 mutation and 39 were found to have compound heterozygosity for the A455E mutation. Login to comment
36 The other mutations found in A455E heterozygotes are all associated with pancreatic insufficiency and have been classified as severe cystic fibrosis mutations,8 predicted to produce no functioning CFTR.14 Therefore, all patients with an A455E allele were analyzed together. Login to comment
40 Analysis for the F508 mutation was carried out by direct polyacrylamide-gel electrophoresis of the CFTR exon 10 product of the polymerase chain reaction16 or as part of a multiplex amplification refractory mutation system.17 For the analysis of the A455E mutation, a specific amplification refractory mutation system was developed (Scheffer H, et al.: unpublished data). Login to comment
42 For A455E compound heterozygotes, the place of birth was recorded, as were the birthplaces and family names of their parents and grandparents, as far as could be ascertained. Login to comment
50 Statistical Analysis Each of the patients with the A455E mutation was matched with the F508 homozygote closest in age, within two years, and of the same sex. Login to comment
60 As far as could be determined, the families of the A455E compound heterozygotes were not related, nor did they come from geographically isolated regions. Login to comment
62 At least four A455E heterozygotes were former cigarette smokers, whereas none of the F508 homozygotes had ever smoked. Login to comment
65 The patients with the A455E mutation had significantly better lung function than did the F508 homozygotes (mean FEV1, 73.9 percent of the predicted value vs. 54.3 percent of the predicted value; P0.002). Login to comment
70 ߤThe following genotypes were identified: A455E/F508 (25 patients), A455E/E60X (4), A455E/G542X (2), A455E/R553X (1), and A455E/1717-1G࢐A (1). Login to comment
76 Characteristics of Pairs of F508 Homozygotes and A455E Compound Heterozygotes Matched According to Sex and Age. Login to comment
78 OF PAIRS F508 HOMOZYGOTES A455E COMPOUND HETEROZYGOTESߤ P VALUE Sex - no. Login to comment
82 (%) 33 9 (27.3) 0 0.004&#b6; Weight - (percentile) 33 61.029.4 53.430.3 NS Height - (percentile) Men 16 21.425.0 42.027.6 0.03ߥ Women 17 38.128.2 38.729.4 NS less prevalent in patients with the A455E mutation, and diabetes mellitus was absent in this group (P0.004). Login to comment
84 The men with the A455E mutation, but not the women, were significantly taller than matched F508 homozygotes. Login to comment
86 The regression line had a slope of 0.0089 for A455E compound heterozygotes and a significantly steeper slope of 0.0178 for F508 homozygotes (P0.02). Login to comment
89 Although the A455E mutation is known to be associated with pancreatic sufficiency,9 the association between A455E or any other cystic fibrosis mutation and milder lung disease has apparently not been found before. Login to comment
94 Mild symptoms in these patients are therefore most likely associated with the presence of the A455E mutation. Login to comment
99 Solid squares represent patients included in the matched-pairs analysis; 4 A455E compound heterozygotes and 21 F508 homozygotes were not included because they were too young for pulmonary-function testing. Login to comment
102 *Includes 31 A455E compound heterozygotes from the present study. Login to comment
106 Frequency of F508 and A455E Mutations in Various Countries. Login to comment
116 The regression line for FEV1 according to age was less steep in A455E compound heterozygotes than in F508 homozygotes, an indication that the progression of pulmonary disease is slower in patients with the A455E mutation. Login to comment
117 A455E is the first CFTR mutation for which an association with mild lung disease could be found. Login to comment

[hide] CFTR regulates outwardly rectifying chloride chann... Cell. 1995 Jun 30;81(7):1063-73. Schwiebert EM, Egan ME, Hwang TH, Fulmer SB, Allen SS, Cutting GR, Guggino WB
CFTR regulates outwardly rectifying chloride channels through an autocrine mechanism involving ATP.
Cell. 1995 Jun 30;81(7):1063-73., [PMID:7541313]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) functions to regulate both Cl- and Na+ conductive pathways; however, the cellular mechanisms whereby CFTR acts as a conductance regulator are unknown. CFTR and outwardly rectifying Cl- channels (ORCCs) are distinct channels but are linked functionally via an unknown regulatory mechanism. We present results from whole-cell and single-channel patch-clamp recordings, short-circuit current recordings, and [gamma-32P]ATP release assays of normal, CF, and wild-type or mutant CFTR-transfected CF airway cultured epithelial cells wherein CFTR regulates ORCCs by triggering the transport of the potent agonist, ATP, out of the cell. Once released, ATP stimulates ORCCs through a P2U purinergic receptor-dependent signaling mechanism. Our results suggest that CFTR functions to regulate other Cl- secretory pathways in addition to itself conducting Cl-.

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126 (<3)Bar graphillustratingpercentcAMP-stimu- latedgenerationofglucose-6--32PinIB3-1cells, IB3-1 cellsstablytransfectedwithan AAVin- vertedterminalrepeatpromotor-drivenwild- typeCFTRviralvector(Eganetal, 1992;Flotte et al., 1993;Schwiebertet al., 1994a),or IB3-1cellstransientlytransfectedwithwild-typeor mutantCFTR(A455E-CFTRandG551D-CFTR).Data areexpressedtopercentchangeversuscontrol.Dataareexpressedasmean_ SEM.Numberinparenthesesisnumberofexperimentsperformed. Login to comment
145 Interestingly, two mutations located in the first nucleotide-binding domain of CFTR, A455E-CFTR, a mutation associated with mild CF pulmonary disease, and G551 D-CFTR, a mutation associated with severe CF lung disease, had different effects on the ability of CFTR to trigger ATP release. Login to comment
146 IB3-1 CF cells transientlytransfected with A455E reestablished cAMP-stimulated ATP release, although the magnitude was not as large compared with wild-type CFTR (Figure 4C). Login to comment
209 Further support for this hypothesis is that CFTR bearing an A455E mutation, which is associated with mild CF lung disease, can induce ATP release, whereas CFTR bearing a more severe G551D mutation fails to trigger ATP release. Login to comment
210 In a separate study, it was shown that both of the mutant forms of CFTR, A455E and G551D, could function as cAMP-activated CI- channels, although the function of G551D was much reduced compared with that of wild-type or A455E CFTR (Fulmer et al., 1995). Login to comment
211 Importantly, only A455E and not G551D could correct cAMP regulation of ORCCs in IB3-1 CF cells (Fulmer et al., 1995). Login to comment
130 (<3)Bar graphillustratingpercentcAMP-stimu- latedgenerationofglucose-6--32P inIB3-1cells, IB3-1 cellsstablytransfectedwithan AAVin- vertedterminalrepeatpromotor-drivenwild- typeCFTRviralvector(Eganetal, 1992;Flotte et al., 1993;Schwiebertet al., 1994a),or IB3-1cellstransientlytransfectedwithwild-typeor mutantCFTR(A455E-CFTRandG551D-CFTR).Data areexpressedtopercentchangeversuscontrol.Dataareexpressedasmean_ SEM.Numberinparenthesesisnumberofexperimentsperformed. Login to comment
149 Interestingly, two mutations located in the first nucleotide-binding domain of CFTR, A455E-CFTR, a mutation associated with mild CF pulmonary disease, and G551 D-CFTR, a mutation associated with severe CF lung disease, had different effects on the ability of CFTR to trigger ATP release. Login to comment
150 IB3-1 CF cells transientlytransfected with A455E reestablished cAMP-stimulated ATP release, although the magnitude was not as large compared with wild-type CFTR (Figure 4C). Login to comment
213 Further support for this hypothesis is that CFTR bearing an A455E mutation, which is associated with mild CF lung disease, can induce ATP release, whereas CFTR bearing a more severe G551D mutation fails to trigger ATP release. Login to comment
214 In a separate study, it was shown that both of the mutant forms of CFTR, A455E and G551D, could function as cAMP-activated CI-channels, although the function of G551D was much reduced compared with that of wild-type or A455E CFTR (Fulmer et al., 1995). Login to comment
215 Importantly, only A455E and not G551D could correct cAMP regulation of ORCCs in IB3-1 CF cells (Fulmer et al., 1995). Login to comment

[hide] Evaluation of repeat administration of a replicati... Hum Gene Ther. 1995 May;6(5):667-703. Crystal RG, Mastrangeli A, Sanders A, Cooke J, King T, Gilbert F, Henschke C, Pascal W, Herena J, Harvey BG, et al.
Evaluation of repeat administration of a replication deficient, recombinant adenovirus containing the normal cystic fibrosis transmembrane conductance regulator cDNA to the airways of individuals with cystic fibrosis.
Hum Gene Ther. 1995 May;6(5):667-703., [PMID:7578402]

Abstract [show]

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112 G55 ID, S5491, A455E, and G542X account for 10-20% of ttie non-delta F508 mutations (33). Login to comment

[hide] Increased incidence of cystic fibrosis gene mutati... Hum Mol Genet. 1995 Apr;4(4):635-9. Pignatti PF, Bombieri C, Marigo C, Benetazzo M, Luisetti M
Increased incidence of cystic fibrosis gene mutations in adults with disseminated bronchiectasis.
Hum Mol Genet. 1995 Apr;4(4):635-9., [PMID:7543317]

Abstract [show]
In order to identify a possible hereditary predisposition to the development of obstructive pulmonary disease of unknown origin, we have looked for the presence of Cystic Fibrosis Transmembrane Regulator (CFTR) gene mutations in unrelated patients with no signs of Cystic Fibrosis (CF). We screened for 70 common mutations, and also for rare mutations by denaturing gradient gel electrophoresis analysis. In this search, different CFTR gene mutations (R75Q, delta F508, R1066C, M1137V and 3667ins4) were found in five out of 16 adult Italian patients with disseminated bronchiectasis, a significant increase over the expected frequency of carriers. Moreover, three rare CFTR gene DNA polymorphisms (G576A, R668C, and 2736 A-->G), not deemed to be the cause of CF, were found in two patients, one of which was a compound heterozygote with R1066C. These results indicate that CFTR gene mutations, and perhaps also DNA polymorphisms, may be involved in the etiopathogenesis of at least some cases of bronchiectasis.

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31 List of CFTR gene mutations and DNA polymorphisms screened Mutations R75Q/X/L, G85E, 394deITT 457TAT->G, R117H 621 + 1G->T 711 + 5G->A L206W 875 + 40 A->G 936 del TA 1001 + 11C->T R334W, R347 P/H/L, 1154insTC A455E, V456F DF5O8 1717-IG->A, 1717-8G->A G542X, G551D, Q552X, R553X P574H 1898 + 3A->G 2183 AA->G, 2184delA, R709X D836Y, 2694 T/G 2752-22 A/G 2789 + 5 G->A, 2790-2 A-»G Q890X 3041-71 G/C 3132delTG 3271 + 18 C-»T, 3272-26 A->G H1054D, G1061R, R1066C/H, A1067T, H1085R, Y1092X, 3320 ins5 D1152H R1162X, 3667ins4, 3737delA, 11234V 3849 + 10 kb C-»T, 3850-1 G-»A SI25IN, S1255P, 3905insT, 3898insC, D127ON, W1282X, R1283M, 4002 A/G 4005 + 1 G-»A N1303 K/H, 4029 A/G D1377H Q1411 X 4404 C/T, 4521 G/A Location e 3 e 4 i 4 i 5 e 6a i 6a e 6b i 6b e 7 e 9 e 10 i 10 e 11 e 12 i 12 e 13 e 14a i 14a i 14b e 15 i 15 e 17a i 17a e 17b e 18 e 19 i 19 e 20 i 20 e2l e 22 e 23 e24 Listing is in order of location along the CFTR gene, e = exon; i = intron. Login to comment
120 Several mutations were searched by restriction analysis: 457 TAT-»G, R334W, R347P/H/L, A455E, Q552X, 3849 + 10 kbC->T, D1270N. Login to comment

[hide] Mechanism of dysfunction of two nucleotide binding... EMBO J. 1995 Mar 1;14(5):876-83. Sheppard DN, Ostedgaard LS, Winter MC, Welsh MJ
Mechanism of dysfunction of two nucleotide binding domain mutations in cystic fibrosis transmembrane conductance regulator that are associated with pancreatic sufficiency.
EMBO J. 1995 Mar 1;14(5):876-83., [PMID:7534226]

Abstract [show]
Variability in the severity of cystic fibrosis (CF) is in part due to specific mutations in the CF transmembrane conductance regulator (CFTR) gene. To understand better how mutations in CFTR disrupt Cl- channel function and to learn about the relationship between genotype and phenotype, we studied two CF mutants, A455E and P574H, that are associated with pancreatic sufficiency. A455E and P574H are located close to conserved ATP binding motifs in CFTR. Both mutants generated cAMP-stimulated apical membrane Cl- currents in heterologous epithelial cells, but current magnitudes were reduced compared with wild-type. Patch-clamp analysis revealed that both mutants had normal conductive properties and regulation by phosphorylation and nucleotides. These mutants had normal or increased Cl- channel activity: A455E had an open-state probability (Po) similar to wild-type, and P574H had an increased Po because bursts of activity were prolonged. However, both mutants produced less mature glycosylated protein, although levels were greater than observed with the delta F508 mutant. These changes in channel activity and processing provide a quantitative explanation for the reduced apical Cl- current. These data also dissociate structural requirements for channel function from features that determine processing. Finally, the results suggest that the residual function associated with these two mutants is sufficient to confer a milder clinical phenotype and infer approaches to developing treatments.

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1 To understand better how mutations in CFTR disrupt Cl- channel function and to learn about the relationship between genotype and phenotype, we studied two CF mutants, A455E and P574H, that are associated with pancreatic sufficiency. Login to comment
2 A455E and P574H are located close to conserved ATP binding motifs in CFTR. Login to comment
5 These mutants had normal or increased Cl- channel activity: A455E had an open-state probability (PO) similar to wild-type, and P574H had an increased PO because bursts of activity were prolonged. Login to comment
27 Two such mutations are located within NBD1: A455E and P574H (Kerem et al., 1990; Kristidis et al., 1992). Login to comment
28 Although these mutations are uncommon, A455E accounts for -10% of CF chromosomes in some areas of The Netherlands and in the Saguenay-Lac St Jean region of Quebec, Canada (Rozen et al., 1992; Gan et al., 1994). Login to comment
29 A455E and P574H affect residues in NBD1 that are located close to the Walker A (residues 458-464) and B (residues 568-572) motifs, respectively. Login to comment
31 Therefore, we tested the hypothesis that A455E and P574H might alter the function of CFTR Cl- channels. Login to comment
33 86 Oxford University Press Results Expression of A455E and P574H generates cAMP-activated CL currents To learn whether A455E and P574H could form regulated Cl- channels in epithelia, we expressed these mutants in cAMP~ N E ._0. -1 P574H cAMPI A455E 'cAMP 5 pA/cm2L 5 min b Fig. 1. cAMP agonists activate apical membrane CF- currents in FRT epithelia expressing A455E and P574H. Login to comment
44 Figure 1 shows that A455E and P574H generated cAMP-stimulated apical Cl- currents, but AF508 did not. Login to comment
45 However, the magnitude of current generated by A455E and P574H was <20% that of wild-type CFTR in the rank order: wild-type CFTR>> P574H > A455E > AF508. Login to comment
46 When we expressed A455E and P574H in HeLa cells and studied them with the whole-cell patch-clamp technique, we found properties qualitatively similar to those observed with wild-type CFTR (Welsh et al., 1992; Riordan, 1993). Login to comment
47 Figure 2 shows data from studies of P574H; similar results were obtained with A455E (data not shown). Login to comment
66 CFTR 0 * I1 -50 * CFTR A A455E * P574H pA Fig. 3. Login to comment
67 Single-channel properties of A455E and P574H. Login to comment
68 (A) Representative single-channel recordings are from excised inside-out membrane patches from HeLa cells transiently expressing wild-type CFTR, A455E or P574H. Login to comment
72 The voltages were -45 (CFTR), -46 (A455E) or -47 mV (P574H). Login to comment
73 (B) Single-channel I-V relationships of CFTR (U), A455E (A) and P574H (A). Login to comment
76 Conductance was CFT'R 7.76 ± 0.14, A455E 7.40 ± 0.25 and P574H 7.84 ± 0.26 pS; n = 6. Login to comment
81 Single-channel properties of A455E and P574H To determine why A455E and P574H generated less macroscopic Cl- current, we examined their single-channel properties in excised, inside-out patches of membrane. Login to comment
83 The tracings show that the single-channel current amplitudes of A455E and P574H were similar to that of wild-type CFTR. Login to comment
86 Figure 3A shows that A455E had a pattern of gating 878 that closely resembled that of wild-type CFTR. Login to comment
92 Figure 3C shows that the PO of A455E was similar to that of wild-type CFTR, whereas the PO of P574H was increased significantly. Login to comment
96 Maximum likelihood A 0.5pA 2s 50OC mV 0.6 PO 0.4 0.2- -0.1 - -1.2 0.0 J- - -0.4 A B pi (/S) al (f/S) pi 02I -- C2 _ ° a1 a2 12 CFTR A455E P574H CFTR A455E P574H Fig. 4. Login to comment
97 Effect of A455E and P574H on single-channel kinetics. Login to comment
100 (B) Effect of A455E and P574H on rate constants determined by the maximum likelihood fit to the model in (A). Login to comment
101 Data are from four CFTR, two A455E and six P574H single-channel patches. Login to comment
103 The voltages were -50 ± 2 (CFTR), -48 ± I (P574H) and -47 ± 1 mV (A455E). Login to comment
120 In two experiments we examined the gating kinetics of single phosphorylated A455E Cl- channels. Login to comment
121 A455E did not alter PI or al, but tended to increase P2 and a2 in both experiments (Figure 4B). Login to comment
124 Regulation of A455E and P574H by intracellular nucleotides Intracellular MgATP regulates CFTR through interactions with the NBDs. Login to comment
127 Therefore, we tested the hypothesis that ATP-dependent regulation of A455E and P574H was altered. Login to comment
129 At each concentration of MgATP tested, A455E had PO values similar to those of wild-type CFTR, whereas P574H had higher values of PO. Login to comment
131 Figure 5B shows that ADP (1 mM) produced an equivalent inhibition of wild-type CFTR, A455E and P574H. Login to comment
133 Analysis of the processing of A455E and P574H The data indicate that the reduced apical membrane Cl- current produced by A455E and P574H cannot be attributed to the reduced function of single mutant channels. Login to comment
139 However, band C production was reduced in A455E and P574H and was not apparent until 12-24 h after infection, and only then as a faint A B CFTR A455E P574H MgATP (mM) Fig. 5. Login to comment
140 Effects of MgATP concentration and ADP on the activity of phosphorylated A455E and P574H channels. Login to comment
142 and intracellular MgATP concentration for A455E, P574H and wild-type CFTR Cl- channels. Login to comment
143 Data points are the mean ± SEM of n = 4-6 for CFTR (-), n = 5 for A455E (A) and n = 3-5 for P574H (0) at each concentration. Login to comment
144 The voltages were -86 ± 1 (CFTR), -49 ± 2 (A455E) and -49 ± 1 mV (P574H). Login to comment
147 (B) Effect of intracellular ADP on the activities of CFTR, A455E and P574H Cl- channels. Login to comment
149 Values are the mean ± SEM of n = 4 for CFTR, A455E and P574H; the voltages were -49 ± 1 (CFTR), -48 ± 2 (A455E) and -52 ± 1 mV (P574H). Login to comment
150 Percent inhibition of NXP0 by 1 mM ADP was CFTR 77 ± 3, A455E 70 ± 3 and P574H 75 ± 6%. Login to comment
156 Although the production of mature band C protein was greatly reduced in A455E and P574H, it was greater than that observed with AF508. Login to comment
157 Discussion Relationship between apical membrane CL currents and the properties of mutant CFTR Because the A455E and P574H mutations cause CF, we hypothesized that Cl- transport would be reduced in cells expressing these mutants. Login to comment
161 If we set each of these variables to 100% for wild-type CFTR, we can then compare the apical Cl- current generated by wild-type and AF508 CFTR with that produced by A455E and P574H. Table I presents values of each variable, the predicted value of fCI(apical) determined by calculating N x i X P0 and the observed value of fCI(apical). Login to comment
164 Thus, these data provide a molecular explanation for the quantitative decrease in cAMP-stimulated apical membrane Cl- current generated by A455E and P574H. Table I. Login to comment
165 Comparison of predicted apical membrane Cl- current, N X i X PO, and measured cAMP-stimulated apical membrane Cl- current, f'(apical), for wild-type and mutant CFTR N i PO N X i X PO fl'(apical) (%) (%) (%) (%) (%) Wild-type 100 100 100 100 100 AF508 4 100 38 1.6 0 A455E 11 100 93 10.5 8 P574H 15 100 139 21.1 17 N, the number of Cl- channels in the apical membrane; i, single-channel current; PO- open-state probability. Login to comment
171 Mechanism of altered gating by A455E and P574H A455 and P574 lie near the conserved Walker A and B motifs of NBD1. Login to comment
177 It is interesting to compare the effect that different mutations in NBD1 had on al: P574H decreased a1, A455E did not change al, and K464A (a mutant of the Walker A lysine of NBDl; Carson and Welsh, 1995) appeared to increase the rate of channel closing. Login to comment
181 Expression of wild-type CFTR, AF508, A455E and P574H. Login to comment
187 The radioactivity in gels of immunoprecipitated and phosphorylated wild-type CFTR, AF508, A455E and P574H was quantitated as described in Materials and methods. Login to comment
188 The values are the mean + SEM of n = 3 for CFTR, AF508, A455E and P574H. Login to comment
190 It is interesting that A455E appeared to increase IP2 and a2, thereby increasing the frequency of transitions within a burst of activity. Login to comment
192 Our data from A455E, plus the finding that P574H altered P2, suggest that the NBDs may also be involved in regulating gating within a burst. Login to comment
193 One possible interpretation of the effect of A455E is that the mutation reduced the height of an energy barrier between the short-lived closed state (C2) and the open state. Login to comment
198 Our data indicate that processing mutations are not necessarily an all-or-none defect; in contrast to AF508, some of the mutant A455E and P574H protein had a glycosylation pattern consistent with processing in the Golgi complex and generated cAMP-stimulated apical Cl- currents. Login to comment
199 We evaluated the processing of A455E and P574H in HeLa and FRT cells incubated at 37°C. Login to comment
203 For example, A455E formed a channel that was misprocessed yet had conductive and regulatory properties very similar to those of wild-type CFTR. Login to comment
209 Implications for cystic fibrosis These data suggest that the mutations A455E and P574H cause CF because they disrupt the processing of CFTR and its delivery to the cell surface. Login to comment
210 However, they also suggest that these mutations are associated with a milder (PS) clinical phenotype because a small amount of the 881 CFTR A kDa 210 - 170- 116 - 98 - AF508 N. A455E I I P574H 4- Band C 4- Band B B band C bands A+B P574H aL mutant protein is processed correctly, retains normal or greater than normal Cl- channel function and thus generates residual cAMP-stimulated apical membrane C1- cur- rents. Login to comment
212 (1994) who demonstrated that rectal biopsies from patients bearing the A455E mutation retain residual Cl- secretion. Login to comment
215 (1994) found that patients with the A455E mutation were PS, but it is not clear whether or not the A455E mutation confers milder lung disease. Login to comment
216 Uncertainty about the severity of lung disease in these patients highlights the difficulty in assessing the clinical phenotype associated with the A455E and P574H1mutations in relatively small numbers of patients. Login to comment
220 These values are in the same range as those found for A455E (8%) and P574H (17%). Login to comment
223 A455E or P574H could prove to be of value in the development of therapies designed to augment the delivery to and the retention of mutant protein at the plasma membrane (Cheng et al., 1990; Lukacs et al., 1993). Login to comment
224 Although AF508 could be used to assess the processing defect, A455E or P574H might prove to be more tractable models for evaluating strategies to correct mislocalization because the processing defect is only partial and the conductance and regulation of the Cl- channels is more nearly normal. Login to comment
226 Such strategies might also be applied to patients bearing the A455E and P574H mutations because they appear to have at least some functional protein present in the plasma membrane. Login to comment
34 -1 P574H cAMPI A455E 'cAMP 5 pA/cm2L 5 min b Fig. 1. cAMP agonists activate apical membrane CF- currents in FRT epithelia expressing A455E and P574H. Login to comment
48 Figure 2 shows data from studies of P574H; similar results were obtained with A455E (data not shown). Login to comment
69 (A) Representative single-channel recordings are from excised inside-out membrane patches from HeLa cells transiently expressing wild-type CFTR, A455E or P574H. Login to comment
74 (B) Single-channel I-V relationships of CFTR (U), A455E (A) and P574H (A). Login to comment
77 Conductance was CFT'R 7.76 &#b1; 0.14, A455E 7.40 &#b1; 0.25 and P574H 7.84 &#b1; 0.26 pS; n = 6. Login to comment
82 Single-channel properties of A455E and P574H To determine why A455E and P574H generated less macroscopic Cl-current, we examined their single-channel properties in excised, inside-out patches of membrane. Login to comment
84 The tracings show that the single-channel current amplitudes of A455E and P574H were similar to that of wild-type CFTR. Login to comment
87 Figure 3A shows that A455E had a pattern of gating 878 that closely resembled that of wild-type CFTR. Login to comment
93 Figure 3C shows that the PO of A455E was similar to that of wild-type CFTR, whereas the PO of P574H was increased significantly. Login to comment
98 Effect of A455E and P574H on single-channel kinetics. Login to comment
102 Data are from four CFTR, two A455E and six P574H single-channel patches. Login to comment
104 The voltages were -50 &#b1; 2 (CFTR), -48 &#b1; I (P574H) and -47 &#b1; 1 mV (A455E). Login to comment
122 A455E did not alter PI or al, but tended to increase P2 and a2 in both experiments (Figure 4B). Login to comment
125 Regulation of A455E and P574H by intracellular nucleotides Intracellular MgATP regulates CFTR through interactions with the NBDs. Login to comment
128 Therefore, we tested the hypothesis that ATP-dependent regulation of A455E and P574H was altered. Login to comment
130 At each concentration of MgATP tested, A455E had PO values similar to those of wild-type CFTR, whereas P574H had higher values of PO. Login to comment
132 Figure 5B shows that ADP (1 mM) produced an equivalent inhibition of wild-type CFTR, A455E and P574H. Login to comment
134 Analysis of the processing of A455E and P574H The data indicate that the reduced apical membrane Cl-current produced by A455E and P574H cannot be attributed to the reduced function of single mutant channels. Login to comment
141 Effects of MgATP concentration and ADP on the activity of phosphorylated A455E and P574H channels. Login to comment

[hide] Cystic fibrosis: genotypic and phenotypic variatio... Annu Rev Genet. 1995;29:777-807. Zielenski J, Tsui LC
Cystic fibrosis: genotypic and phenotypic variations.
Annu Rev Genet. 1995;29:777-807., [PMID:8825494]

Abstract [show]
Cystic fibrosis (CF) is a common genetic disorder in the Caucasian population. The gene was identified in 1989 on the basis of its map location on chromosome 7. The encoded gene product, named cystic fibrosis transmembrane conductance regulator (CFTR), corresponds to a cAMP-regulated chloride channel found almost exclusively in the secretory epithelial cells. Although the major mutation that results in a single amino acid deletion (F508) accounts for 70% of the disease alleles, more than 550 additional mutant alleles of different forms have been detected. Many of these mutations can be divided into five general classes in terms of their demonstrated or presumed molecular consequences. In addition, a good correlation has been found between CFTR genotype and one of the clinical variables--pancreatic function status. An unexpected finding, however, is the documentation of CFTR mutations in patients with atypical CF disease presentations, including congenital absence of vas deferens and several pulmonary diseases. Thus, the implication of CFTR mutation is more profound than CF alone.

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551 FIBROSIS Table 1 Most common CFTR mutations in the world Name of Mutation �F508 0542X 0551D NI303K WI282X R553X 621 + 10 � T 1717-10 � A RI17H R1162X R347P 3849 + IOkbC � T �1507 394delTT 085E R560T A455E 1078deiT 2789 + SO � A 3659deiC R334W 1898 + 10 � T 711 + 10 --. Login to comment
628 This strategy may also be applied to patients with other Normal II III IV V No synthesis Block in Block in Altered Reduced processing regulation conductance synthesis Nonsense Missense G542X Missense Missense Missense A455E Frameshift N1303K G551D R117H 394deiTT AA deletion Alternative L1F508 R347P splicing Splice junction 1717-1G-->A 3849+1OkbC-->T Figure 3 Molecular consequence of different classes ofCF mutations. Login to comment
644 Several missense mutations (e.g. P574H and A455E) are reasoned to have mild molecular consequence because they are found associated with pancreatic sufficiency-a mild phenotype (lOS). Login to comment
654 One study based on a small number of PS patients suggests a correlation between A455E mutation and mild pulmonary presentation (76). Login to comment

[hide] Detection of more than 50 different CFTR mutations... Hum Genet. 1994 Nov;94(5):533-42. Dork T, Mekus F, Schmidt K, Bosshammer J, Fislage R, Heuer T, Dziadek V, Neumann T, Kalin N, Wulbrand U, et al.
Detection of more than 50 different CFTR mutations in a large group of German cystic fibrosis patients.
Hum Genet. 1994 Nov;94(5):533-42., [PMID:7525450]

Abstract [show]
We have conducted a comprehensive study of the molecular basis of cystic fibrosis (CF) in 350 German CF patients. A screening approach based on single-strand conformation analysis and direct sequencing of genomic polymerase chain reaction products has allowed us to detect the molecular defects on 95.4% of the CF chromosomes within the coding region and splice sites of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The spectrum of sequence changes comprises 54 different mutations, including 17 missense mutations, 14 nonsense mutations, 11 frameshift mutations, 10 splice site variants and two amino acid deletions. Eleven of these mutations have not previously been described. Our results reflect the marked mutational heterogeneity of CF in a large sample of patients from a non-isolated population.

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77 Table 1 Frequency distribution and haplotypes of CFTR mutations in 700 German CF chromosomes Mutation~ Nucleotide changesb Locationc Frequencyd Haplotype~ Referencef Q39x C--~T at 247 Exon 2 1 (0.1%) D3 Cutting et al. (1992) E60X G-+T at 310 Exon 3 1 (0.1%) A2 Malone et al. (*) R75X C--+T at 355 Exon 3 1 (0.1%) C2 This study 405+1 G---~A G-+A at 405+1 Intron 3 1 (0.1%) C2 D6rk et al. (1993c) E92X G--~T at 406 Exon 4 2 (0.3%) B2 Will et al. (1994) R117C C---~Tat 481 Exon 4 1 (0.1%) C2 This study R117H G--+A at 482 Exon 4 2 (0.3%) B6 Dean et al. (1990) 621+1 G--+T G--+T at 621+1 Intron 4 1 (0.1%) B1 Zielenski et al. (1991b) H199Y C--+T at 727 Exon 6a 1 (0.1%) A2 This study (*) 1078delT Deletion of T at 1078 Exon 7 4 (0.6%) C2 Claustres et al. (1992) R334W C-~T at 1132 Exon 7 2 (0.3%) BI Gasparini et al. (1991) 1336K T-->A at 1139 Exon 7 3 (0.4%) A2 Cuppens et al. (1993) R347P G--+C at 1172 Exon 7 11 (1.6%) A2, C2 Dean et al. (1990) 1342-2 A--+C A--+C at 1342-2 Intron 8 3 (0.4%) A4 D/3rk et al. (1993b) Q414X C--+T at 1372 Exon 9 1 (0.1%) D3 D6rk et al. (1994a) A455E C-+A at 1496 Exon 9 1 (0.1%) BI Kerem et al. (1990) V456F G--~T at 1498 Exon 9 1 (0.1%) B3 D6rk et al. (1994a) A1507 Deletion of 3 bp between 1648-1653 Exon 10 1 (0.1%) D5 Kerem et al. (1990) AF508 Deletion of 3 bp between 1652-1655 Exon 10 504 (72.0%) B1, DI, B7 Kerem et al. (1989) 1717-1 G--+A G--+A at 1717-1 lntron 10 6 (0.9%) B3 Kerem et al. (1990) G542X G--+T at 1756 Exon 11 10 (1.4%) B1 Kerem et al. (1990) G551D G--+A at 1784 Exon 11 7 (l.0%) B3 Cutting et al. (1990) Q552X C-+T at 1786 Exon 11 1 (0.1%) A4 Devoto et al. (1991) R553X C--+T at 1789 Exon 11 16 (2.3%) A4, B4, D3 Cutting et al. (1990) L558S T--+C at 1805 Exon 11 1 (0.1%) C2 Maggio et al. (*) 1811+I.6kBA-+G A--+Gat 1811+l.6kB lntron 11 1 (0.1%) A2 Chillonetal. Login to comment

[hide] Association of pancreatic adenocarcinoma, mild lun... Clin Chem. 1994 Oct;40(10):1972-4. Tsongalis GJ, Faber G, Dalldorf FG, Friedman KJ, Silverman LM, Yankaskas JR
Association of pancreatic adenocarcinoma, mild lung disease, and delta F508 mutation in a cystic fibrosis patient.
Clin Chem. 1994 Oct;40(10):1972-4., [PMID:7522998]

Abstract [show]
A case of adenocarcinoma of the pancreas and mild lung disease in a 39-year-old man homozygous for the delta F508 cystic fibrosis mutation is presented. Cystic fibrosis is the most common lethal genetic disease in Caucasians, and is most commonly associated with severe obstructive lung disease. To our knowledge, this is only the fifth case of adenocarcinoma of the pancreas in a CF patient to be reported and the first case for which molecular data are available. The rare incidence of this type of malignancy in the general population suggests a possible association of CF with this malignant disease.

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44 CorrelatIon of phenotype and genotype of CFTR mutations Key phenotypic Lung disease SweatC1 Exocnne pancreas function Vasdeferens Associated CFTR mutations Pancreatic InsuffIcIent Pancreatic sufficient Normalsweat C1 Severe Less severe Relatively mild Elevated Elevated Normal Insufficient Sufficient Sufficient Absent Absent Absent SF508, G542X, R553X, G5510, Ni 303K, Wi 282X, RI 17H, and others 2789 + 5G>A, R117H, R334W, R347P, A455E, P574H, S945L, G85E, and others G551S, R117H, 3849 + 10kb C>T, and others Congenitalabsence of the vas deferens None Normal or elevated Sufficient Absent F508C, Ri 17H, Di D1152H, and others FIg. 2. Login to comment

[hide] Mutation analysis in 600 French cystic fibrosis pa... J Med Genet. 1994 Jul;31(7):541-4. Chevalier-Porst F, Bonardot AM, Gilly R, Chazalette JP, Mathieu M, Bozon D
Mutation analysis in 600 French cystic fibrosis patients.
J Med Genet. 1994 Jul;31(7):541-4., [PMID:7525963]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) gene of 600 unrelated cystic fibrosis (CF) patients living in France (excluding Brittany) was screened for 105 different mutations. This analysis resulted in the identification of 86% of the CF alleles and complete genotyping of 76% of the patients. The most frequent mutations in this population after delta F508 (69% of the CF chromosomes) are G542X (3.3%), N1303K (1.8%), W1282X (1.5%), 1717-1G-->A (1.3%), 2184delA + 2183 A-->G (0.9%), and R553X (0.8%).

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21 Among the 104 other CFTR mutations tested on the 373 non-AF508 CF chromosomes, none of the following 58 mutations were found: G91R, 435 insA, 444delA, D11OH, 556delA, 557delT, R297Q, 1154insTC, R347L, R352Q, Q359K/T360K, 1221delCT, G480C, Q493R, V520F, C524X, 1706dell7, S549R (A-C), S549N, S549I, G551S, 1784delG, Q552X, L558S, A559T, R560T, R560K, Y563N, P574H, 2307insA, 2522insC, 2556insAT, E827X, Q890X, Y913C, 2991de132 (Dork et al, personal communication), L967S, 3320ins5, 3359delCT, H1085R, R1158X, 3662delA, 3667del4, 3667ins4, 3732delA, 3737delA, W1204X, 3750delAG, I 1234V, Q1238X, 3850- 3T-+G, 3860ins31, S1255X, 3898insC, D1270N, R1283M, F1286S, 4005 + I G-A. Forty-six other mutations were found on at Distribution of CFTR mutations found in our sample ofpopulation (1200 CF chromosomes) Mutations tested No of CF chromosomes Haplotypes Method with the mutation XV2C-KM19 (% of total CF alleles) Exon 3: G85E 4 (033) 3C HinfI/ASO394delTT 2 2B PAGEExon 4: R117H 1 B ASOY122X 2 2C MseI/sequenceI148T 1 B ASO621+IG-J* 1 B MseIIASOExon 5: 711+1G--T 8(07) 8A ASOExon 7: AF311 1 C PAGE/sequencelO78delT 5 (0-42) 5C PAGE/ASOR334W 5 (0-42) 2A,2C,ID MspIlASOR347P 5 (042) 5A CfoI/NcoIR347H 1 Cfol/sequenceExon 9: A455E 1 B ASOExon 10: S492F I C DdeI/sequenceQ493X 1 D ASOl609deICA 1 C PAGE/Ddel/sequenceA1507 3 (025) 3D PAGE/ASOAF508 827 (69) 794B,30D,2C,IA PAGEl677delTA 1 A PAGE/sequenceExon I11: 1717-IG--.A 16(1-3) 14B Modified primers + AvaIIG542X 40 (3-3) 29B,5D,2A Modified primers + BstNiS549R(T--*G) 2 2B ASOG551D 3 (025) 3B HincII/Sau3AR553X 10(0-8) 6A,1B,2C,ID Hincll/sequenceExon 12: 1898+IG--A 1 C ASO1898+ IG-C 2 IC ASOExon 13: l9l8deIGC 1 A PAGE/sequence1949de184 I C PAGE/sequenceG628R(G-+A) 2 2A Sequence2118de14 I c PAGE/sequence2143de1T 1 B PAGE/modified primers2184de1A+2183A--*G 11 (0-9) lIB PAGE/ASO2184de1A 1 ASOK710X 3 (025) IC XmnI2372de18 1 B PAGE/sequenceExon 15: S945L 1 C TaqlExon 17b:L1065P I MnlIL1077P 1 A ASOY1092X 3 (025) 2C,IA Rsal/ASOExon 19: RI1162X 6 (0-5) 5C,IA DdeI/ASO3659delC 3 (025) 3C ASOExon 20: G1244E 2 2A MboIIS1251N 2 2C RsaI3905insT 4 (0-33) 4C PAGE/ASOW1282X 18 (105) 15B,1D MnlI/ASOR1283K 1 C Mnll/sequenceExon 21: N1303K 22 (1-8) 18B,lA,ID Modified primers+BstNI 47 mutations 1031 (85 9) least one CF chromosome (table): 21 of them are very rare as they were found on only one CF chromosome in our population. Login to comment

[hide] CFTR haplotype backgrounds on normal and mutant CF... Hum Mol Genet. 1994 Apr;3(4):607-14. Cuppens H, Teng H, Raeymaekers P, De Boeck C, Cassiman JJ
CFTR haplotype backgrounds on normal and mutant CFTR genes.
Hum Mol Genet. 1994 Apr;3(4):607-14., [PMID:7520797]

Abstract [show]
Ten polymorphic loci, located in a 1 Mb interval across the cystic fibrosis locus, were analyzed on normal and mutant CFTR genes. A different distribution of haplotype backgrounds among normal and mutant CFTR genes was observed. With exception of the D7S8 locus, the three most common mutations, delta F508, G542X and N1303K, were found on an identical haplotype background. In agreement with the observed linkage equilibrium between the Q1463Q and D7S8 loci, both alleles at the D7S8 locus were found on delta F508 CFTR genes. However, the G542X and N1303K mutations, which have been estimated to be at least 35000 years old, were found to be associated with a single allele at the D7S8 locus. Absence of recombination between the D7S8 and Q1463Q loci was also observed on normal CFTR genes with this haplotype background. At the Tn locus in intron 8, allele 9 known to result in very efficient splicing was associated with the most frequent mutations. At the M470V locus, located in a conserved region of the first nucleotide binding fold, the amino acid methionine was found to be associated with the frequent mutations, in particular with mutations located in one of the two nucleotide binding folds which are generally known as severe mutations with regard to exocrine pancreatic function. On mutant CFTR gene, this locus was in complete association with the centromeric D9 locus, in the absence of a complete association with the intervening loci.(ABSTRACT TRUNCATED AT 250 WORDS)

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34 Distribution of alleles at 10 polymorphic loci Locus Allele Normal Mutant Mutations XV2c KM19 D9 1 2 1 2 1 2 58 (0.492) 60 (0.508) 84 (0.622) 51 (0.378) 78 (0.586) 55 (0.414) 146 (0.918) 13 (0.082) 19(0.109) 156 (0.891) 15 (0.085) 161 (0.915) 1001 + llC/T Tn 115 (0.927) R 9 (0.073) 5 7 (0.057) 7 102 (0.836) 9 13 (0.107) M470V C 62 (0.496) R 63 (0.504) 1898+15 2T/A C 84(0.641) R 47 (0.359) T854T Q1463Q D7S8 C 82 (0.636) R 47 (0.364) C 90 (0.692) R 40 (0.308) 1 38 (0.317) 2 82 (0.683) 33 (0.192) 139 (0.808) 0 (0.000) 32 (0.190) 136 (0.810) 156 (0.902) 17 (0.098) 163 (0.926) 13 (0.074) 162 (0.926) 13 (0.074) 162 (0.931) 12 (0.069) 91 (0.569) 69 (0.431) E60X, 622-2A-C, A455E, AF508 (98.3%), 1717-1G-A, G542X, 0.479 63.54 G628R(G-C)/S1235R,2183AA-G, G970R, W1282X, N1303K p<10~ G458V, AI5O7, AF508 (1.7%), 1898 + 1G-C, E73OX, 3272-26A-G, W1310X, 4218insT, UA, UB, UC I336K, W401X, 2T2ldelll, Y1092X, 3659delC, S1251N: not included (5%) E60X, 622-2A-C, W401X, G458V, AF5O8 (1.6%), 1898+ 1G-C, -0.541 90.63 G628R(G-Q/S1235R, E730X, G970R, 3272-26A-G (50.0%), p<10" Y1092X, 3659delC, S1251N, W1310X, UB, UTC A455E, AI507, AF5O8 (98.4%), 1717- 1G-A, G542X, 2183AA-G, 3272-26A-G (50.0%), W1282X, N13O3K, 4218insT, UA 1336K, 2721delU: not included (1%) E60X, 622-2A-C, W401X, G458V, 1898 +1G-C, E730X, G970R, -0.541 90.46 Y1092X, 3659delC, S1251N, W1310X, UB, UC p<10" A455E, AI507, AF508, 1717- 1G-A, G542X, G628R(G-Q/S1235R, 2183AA-G, 3272-26A-G, W1282X, N13O3K, 4218insT, UA I336K, 2721delll: not included (1%) E60X, 622-2A-C, I336K, W401X, G458V, AI507, 1717- 1G-A, -0.726 155.94 1898 + 1G-C, G628R(G-C)/S1235R, 2183AA-G, E730X, 2721delll, p< 10" G970R, 3272-26A-G, Y1092X, 3659delC, S1251N, W1282X, W1310X, 4218insT, UA, UB, UC A455E, AF5O8, G542X, N13O3K E60X, 622-2A-C, I336K, W401X, G458V, AI507, 1717-1G-A, 1898 + 1G-C, G628R(G-C)/S1235R, 2183AA-G, E730X, 2721delll, G970R, 3272-26A-G, Y1092X, 3659delC, S1251N, W1282X, W1310X, 4218insT, UA, UB, UC A455E, AF5O8, G542X, N13O3K A455E, AI5O7, AF508, 1717-1G-A, G542X, G628R(G-Q/S1235R, 2183AA-G, 3272-26A-G, W1282X, N13O3K, 4218insT, UA E60X, 622-2A-C, W401X, G458V, 1898 + 1G-C, E730X, G970R, Y1092X, 3659delC, S1251N, W1310X, UB, UC 1336K, midclll: not included (1%) E60X, 622-2A-C, W401X, A455E, G458V, AF508 (99.2%), G542X, 1898 + 1G-C, 2183AA-G, E730X, G970R, Y1092X, 3659delC, S1251N, N1303K, W1310X, UB, UC AI507, AF5O8 (0.8%), 1717-1G-A, G628R(G-Q/S1235R, 3272-26A-G, W1282X, 4218insT, UA I336K, 2721delU: not included (1%) E60X, 622-2A-C, W401X, A455E, G458V, AF508 (99.2%), G542X, 1898+1G-C, 2183AA-G, E730X, G970R, Y1092X, 3659delC,S1251N, N13O3K, W1310X, UB, UC AI507, AF508 (0.8%), 1717-1G-A, G628R(G-C)/S1235R, 3272-26A-G, W1282X, 4218insT, UA 1336K, midelll: not included (1%) E60X, 622-2A-C, W401X, A455E, G458V, AF5O8 (99.2%), G542X, G628R(G-Q/S1235R, 2183AA-G, E730X, G970R, Y1092X, 3659delC, S1251N,N1303K, W1310X, UC AI507, AF5O8 (0.8%), 1717-1G-A, 1898 + 1G-C, 3272-26A-G, W1282X, 4218insT 1336K, 2721del11. Login to comment
35 UA, UB: not included (2%) A455E, AF508 (61.2%), 1717-1G-A (66.7%), G542X, G628R(G-C)/S1235R, 3272-26A-G, S1251N, W1282X, W1310X E60X, 622-2A-C, W401X, G458V, AJ507, AF5O8 (38.8%), 1717- 1G-A (33.3%), 1898 +1G-C, 2183AA-G, E730X, G970R, Y1092X, 3659delC, N13O3K, 4218insT, UA, UB, UC 1336K, 2721delll: not included (1%) -0.694 139.81 p<10~ 0.452 60.83 p<10" 0.355 38.77 p<10" 0.360 39.44 p<10~7 0.314 29.91 0.250 17.54 p<10"4 The observed CFTR genes associated with a particular allele are given, proportions are given between brackets. Not all the mutations were informative for each of the tested loci, which were therefore not included. For the Tn locus the standardized linkage disequilibrium coefficient was calculated for the group of the non-T9 alleles and the T9 alleles. Login to comment
72 Extragenic (XV2c/KM19/D9) haplotypes Haplotype Normal Mutant Mutations 111 211 121 112 212 122 222 23 (0.204) 43 (0.381) 2 (0.018) 6 (0.053) 0 (0.000) 22 (0.195) 17 (0.150) 4 (0.026) E60X, 622-2A-C, G970R 6 (0.039) G458V, 1898+1G-C, E73OX, W1310X, UB, UC 0 (0.000) 3 (0.019) AF5O8 (1.7%), G628R(G-Q/S1235R 1 (0.006) 3272-26A-G (50.0%) 134 (0.870) A455E, AF508 (96.5%), 1717-1G-A, G542X, 2183AA-G, W1282X, N13O3K 6 (0.039) AI507, AF508 (1.8%), 3272-26A-G (50.0%), 4218insT, UA p<10"3 p<10"7 p<10~7 p<10"2 The observed CFTR genes associated with a particular haplotype are given, proportions are given between brackets. Login to comment
103 CFTR haplocypes I II ma mb rv V VI Haplotype C7RCCC 211C7RCCC1 111C7RCCC1 /11C7RCCC1 211C7RCCC2 111C7RCCC2 /11C7RCCC2 122C7RCCC2 121C7RCCC2 C5CRRR 122C5CRRR1 211C5CRRR2 222C5CRRR2 C7CRRR 122C7CRRR1 222C7CRRR1 212C7CRRR1 122C7CRRR2 222C7CRRR2 122C7CRRR/ C9CRRR 211C9CRRR1 R9CCCC 122R9CCCC1 222R9CCCC1 /22R9CCCC1 112R9CCCC1 122R9CCCC2 222R9CCCC2 112R9CCCC2 R9CRRR 122R9CRRR1 C7CRRC 112C7CRRC1 112C7CRRC2 C9CRRC 211C9CRRC1 C7CCCC 211C7CCCC1 222C7CCCC1 122C7CCCC2 C7RCCR 211C7RCCR2 Normal 0.524 (43) 0.085 0.073 0.195 0.146 0.012 0.012 0.049 (4) 0.012 0.024 0.012 0.220 (18) 0.024 0.073 0.000 0.073 0.049 0.012 (1) 0.012 0.073 (6) 0.000 0.000 0.000 0.061 0.012 0.000 0.000 (0) 0.000 0.061 (5) 0.000 0.061 0.012 (1) 0.012 0.037 (3) 0.012 0.024 0.000 0.012 (1) 0.012 Mutant 0.080 (IS) 0.005 0.000 0.020 0.015 0.020 0.020 0.000 0.000 0.000 (0) 0.000 0.000 0.000 Mutations p<10"7 W1310X S1251N G458V, E730X, UC E60X, 622-2A-C, G970R W401X, Y1092X, 3659delC 0.055 (9) p<10"2 0.017 0.005 0.005 0.008 0.010 0.010 0.000 (0) 0.000 1717-1G-A (66.7%) 50.0% of 3272-26A-G 50.0% of 3272-26A-G 1717-1G-A(33.3%) AI507, 4218insT W1282X 0.819 (130) p<10~7 0.466 0.007 0.010 0.007 0.312 0.007 0.007 0.005 (1) 0.005 0.005 (1) 0.005 0.000 0.000 (0) 0.000 0.010 (2) 0.000 0.000 0.010 0.005 (1) 0.005 56.7% of AF508, G542X 1% of AF5O8 A455E 1% of AF5O8 38.1% of AF508, N1303K 1.0% of AF5O8 1% of AF508 1% of AF508 G628R(G-Q/S1235R 2183AA-G 1898+1G-C The proportion of CFTR genes associated with a particular haplotype, and the mutations found to be associated with that haplotype are given. Login to comment
134 The 3 most frequent mutations together with the A455E mutation were associated with allele R, all other CFTR mutations were associated with allele C. Login to comment
150 The 4 mutations that were also associated with the R allele at the 1001 + 11C/T locus were associated with the 9T allele, i.e. the three most common CF mutations and the A455E mutation. Login to comment
151 The A455E mutation is located in exon 9 itself, in which only a limited number of mutations have been identified. Login to comment
153 A major difference between these two mutations is that G458V is considered as a severe mutation (23), while A455E is known as a mild mutation with regard to pancreatic involvement (10). Login to comment

[hide] Exon 9 of the CFTR gene: splice site haplotypes an... Hum Genet. 1994 Jan;93(1):67-73. Dork T, Fislage R, Neumann T, Wulf B, Tummler B
Exon 9 of the CFTR gene: splice site haplotypes and cystic fibrosis mutations.
Hum Genet. 1994 Jan;93(1):67-73., [PMID:7505767]

Abstract [show]
The alternatively spliced exon 9 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene codes for the initial part of the amino-terminal nucleotide-binding fold of CFTR. A unique feature of the acceptor splice site preceding this exon is a variable length polymorphism within the polypyrimidine tract influencing the extent of exon 9 skipping in CFTR mRNA. We investigated this repeat for its relationship to CFTR mutations and intragenic markers on 200 chromosomes from German patients with cystic fibrosis (CF). Four frequent length variations were strongly associated with the four predominant haplotypes previously defined by intragenic marker dimorphisms. One of these alleles displayed absolute linkage disequilibrium to the major CF mutation delta F508. Other frequent CFTR mutations were linked to one particular splice site haplotype indicating that differential exon 9 skipping contributes little to the clinical heterogeneity among CF patients with an identical mutation. We also identified a novel missense mutation (V456F) and a novel nonsense mutation (Q414X) within the coding region of exon 9. The missense mutation V456F adjacent to Walker motif A was present in a pancreas-sufficient CF patient. In contrast, the pancreas-insufficient Q414X/delta F508 compound heterozygote suffered from a severe form of the disease, indicating that alternative splicing of exon 9 does not overcome the deleterious effect of a stop codon with this exon.

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61 Association of (TG),Tm alleles with CFTR mutations (TG),Tm CFTR mutationsa (TG)llT7 E60X, E92X, R117C, 1078delT, R347P, R553X, 2184delA, 2184insA, I1005R, 3272-26A--~G, L1059X, Y1092X, R1162X, 3659delC, 3850-3T-oG, S1251N Q39X, R117H, Q414X, V456F, AI507, 1717-1G--~A, G551D, 2043delG, 2183AA---~G, 2184insA, 2789 + 5 G---~A,3272-26A---~G, R1066C, L1077P, 3849 + l0 kB C---~T,4374 + 1 G---~T 621 + 1 G---~T,R334W, A455E, AF508, G542X, 2143delT, 3849 + 10 kB C---~T,NI303K 405 + 1 G----~A,1342-2 A---~C,R553X (TG)IoT7 (TG)10T9 (TG)12T7 a References are compiled in Tsui (1992), except for 2143delT (Dtrk et al. 1992b), 3850-3 T---~G,4374 + 1 G---~T,1342-2 A---~C (Dtrk et al. 1993a, b), Q414X, V456F (this work), 405 + 1 G---~A, E92X, R117C, 2184delA, 2184insA, I1005R, L1059X (T. Login to comment
75 The missense mutations A455E and V456F are both located in front of the conserved Walker motif A (Riordan et al. 1989; Walker et al. 1982). Login to comment
76 A455E has previously been described (Kerem et al. 1990) and is reported to be frequent in French-Canadians (Rozen et al. 1992). Login to comment
77 We confirmed A455E in a single German CF female with AF508 on her other chromosome. Login to comment
81 The mutations A455E and V456F both destroy the same recognition site for the restriction enzyme AciI. Login to comment
115 Early evidence for a crucial role of exon 9 sequences came from the findings that mutations 71 within or adjacent to the Walker motif A produce a CF phenotype in vivo (A455E, G458V; Kerem et al. 1990; Cuppens et al. 1990) and in vitro (K464A; Anderson and Welsh 1992). Login to comment

[hide] Detection of 98.5% of the mutations in 200 Belgian... Genomics. 1993 Dec;18(3):693-7. Cuppens H, Marynen P, De Boeck C, Cassiman JJ
Detection of 98.5% of the mutations in 200 Belgian cystic fibrosis alleles by reverse dot-blot and sequencing of the complete coding region and exon/intron junctions of the CFTR gene.
Genomics. 1993 Dec;18(3):693-7., [PMID:7508414]

Abstract [show]
We have previously shown that about 85% of the mutations in 194 Belgian cystic fibrosis alleles could be detected by a reverse dot-blot assay. In the present study, 50 Belgian chromosomes were analyzed for mutations in the cystic fibrosis transmembrane conductance regulator gene by means of direct solid phase automatic sequencing of PCR products of individual exons. Twenty-six disease mutations and 14 polymorphisms were found. Twelve of these mutations and 3 polymorphisms were not described before. With the exception of one mutant allele carrying two mutations, these mutations were the only mutations found in the complete coding region and their exon/intron boundaries. The total sensitivity of mutant CF alleles that could be identified was 98.5%. Given the heterogeneity of these mutations, most of them very rare, CFTR mutation screening still remains rather complex in our population, and population screening, whether desirable or not, does not appear to be technically feasible with the methods currently available.

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43 TABLE 1 Mutations (and Their Frequencies) Identified in This Study Predicted amino Mutation Nucleotide change~ acid change Location Frequencyb Reference E60X G --~ T at 310 (TAGATAGCT) Glu --~ Stop at 60 Malone et al. in (21); this study G --~ A at 482 (GAACACTCT) (8) A --~ C at 622-2 (TTTTCGACT) This study T --~ A at 1139 (AAAAAATTC) This study G --~ A at 1335 (TCTGAGAGG) This study C --~ A at 1496 (TTGGAGGTT) (14) G -~ T at 1505 (GCTGTATCC) (6) Deletion of ATC from 1651 (14); Schwarz et al. (TATC_TTTG) in (21) Deletion of CTT from 1653 145 (13) (TCAT_TGGT) G --~ A at 1717-1 (AATAAGACA) G --~ T at 1756 (TCTTTGAGA) G --~ C at 1898 + 1 (AAAGCTATG) G --~ C at 2014 (TTATCGGAC Deletion of A at 2184; A --~ G at 2183 (AAAAG CAAT) G --~ T at 2320 (TGATTAGCC Deletion of 11 nucleotides from 2721 (TGCT_TAGT) G --~ C at 3040 (AGCACGTAC A --~ G at 3272-26 (TGCAGTGTT) C --~ A at 3408 (TGTAACTGT) Deletion of C at 3659 (CCTA_CAAG) T --~ G at 3837 (TAAGGCCTG G --* A at 3884 (AAGAATACT G --~ A at 3978 (AGTGAAGGA' C --~ G at 4041 (AAAAGTTGG G -~ A at 4061 (CAGTAGAGT Insertion of T after 4218 (CAGTTAAGG) R117H 622-2A --~ C I336K W401X A455E G458V AI507 AF508 1717-1G -~ A G542X 1898+ 1G-~C G628R(G -~ C) 2184delA plus A -~ G at 2183 E730X 2721de111 G970R 3272-26A --~ G Y1092X 3659delc $1235R $1251N W1282X N1303K W1310X 4218insT Exon 3 2 (1.0%) Arg --~ His at 117 Exon 4 c 3' splice signal Intron 4 1 (0.5%) Ile -~ Lys at 336 Exon 7 1 (0.5%) Trp --~ Stop at 401 Exon 8 2 (1.0%) Ala --~ Glu at 455 Exon 9 2 (1.0%) Gly --* Val at 458 Exon 9 1 (0.5%) Deletion of Ile 507 Exon 10 1 (0.5%) Deletion of Phe 508 Exon 10 (72.5%) 3' splice signal Intron 10 5 (2.5%) Gly --* Stop at 542 Exon 11 11 (5.5%) 5' splice signal Intron 12 1 (0.5%) Gly -~ Arg at 628 Exon 13 1 (0.5%) Frameshift Exon 13 2 (1.0%) Glu --~ Stop at 730 Exon 13 1 (0.5%) Frameshift Exon 14a I (0.5%) Gly --~ Arg at 970 Exon 15 1 (0.5%) 5' splice signal? Login to comment
48 The G628R(G --~ C) and $1235R mutations were found on a single allele; the W1310X allele and one 2184delA (plus A --~ G at 2183) allele were found on a CFTR gene from Turkish descent. Login to comment
49 For each type mutation, at least one allele was completely sequenced: 14 for AF508, 3 for G542X, 2 for 1717-1G -~ A, 1 for A455E, 1 for G458V, 1 for AI507, 1 for W1282X, 1 for N1303K, and for the remainder, the total number of alleles that were found in this study. Login to comment
105 The fact that the G458V/G542X individual has CF suggests that the alternatively spliced 9- CFTR mRNA transcript cannot compensate for the basic defect of the CFTR protein in this CF patient. Login to comment
106 This was also seen in another CF patient, who was a compound heterozygote for the A455E and Y1092X mutations, A455E also being located in exon 9. Login to comment
107 The A455E allele carried nine thymidines in its poly-(T) tract. Login to comment
108 The parent of the A455E/Y1092X compound heterozygote, carrying the A455E allele, carried five thymidines in the poly-(T) tract on the normal CFTR allele (data not shown). Login to comment
42 TABLE 1 Mutations (and Their Frequencies) Identified in This Study Predicted amino Mutation Nucleotide change~ acid change Location Frequencyb Reference E60X G --~ T at 310 (TAGATAGCT) Glu --~ Stop at 60 Malone et al. in (21); this study G --~ A at 482 (GAACACTCT) (8) A --~ C at 622-2 (TTTTCGACT) This study T --~ A at 1139 (AAAAAATTC) This study G --~ A at 1335 (TCTGAGAGG) This study C --~ A at 1496 (TTGGAGGTT) (14) G -~ T at 1505 (GCTGTATCC) (6) Deletion of ATC from 1651 (14); Schwarz et al. (TATC_TTTG) in (21) Deletion of CTT from 1653 145 (13) (TCAT_TGGT) G --~ A at 1717-1 (AATAAGACA) G --~ T at 1756 (TCTTTGAGA) G --~ C at 1898 + 1 (AAAGCTATG) G --~ C at 2014 (TTATCGGAC Deletion of A at 2184; A --~ G at 2183 (AAAAG CAAT) G --~ T at 2320 (TGATTAGCC Deletion of 11 nucleotides from 2721 (TGCT_TAGT) G --~ C at 3040 (AGCACGTAC A --~ G at 3272-26 (TGCAGTGTT) C --~ A at 3408 (TGTAACTGT) Deletion of C at 3659 (CCTA_CAAG) T --~ G at 3837 (TAAGGCCTG G --* A at 3884 (AAGAATACT G --~ A at 3978 (AGTGAAGGA' C --~ G at 4041 (AAAAGTTGG G -~ A at 4061 (CAGTAGAGT Insertion of T after 4218 (CAGTTAAGG) R117H 622-2A --~ C I336K W401X A455E G458V AI507 AF508 1717-1G -~ A G542X 1898+ 1G-~C G628R(G -~ C) 2184delA plus A -~ G at 2183 E730X 2721de111 G970R 3272-26A --~ G Y1092X 3659delc $1235R $1251N W1282X N1303K W1310X 4218insT Exon 3 2 (1.0%) Arg --~ His at 117 Exon 4 c 3' splice signal Intron 4 1 (0.5%) Ile -~ Lys at 336 Exon 7 1 (0.5%) Trp --~ Stop at 401 Exon 8 2 (1.0%) Ala --~ Glu at 455 Exon 9 2 (1.0%) Gly --* Val at 458 Exon 9 1 (0.5%) Deletion of Ile 507 Exon 10 1 (0.5%) Deletion of Phe 508 Exon 10 (72.5%) 3' splice signal Intron 10 5 (2.5%) Gly --* Stop at 542 Exon 11 11 (5.5%) 5' splice signal Intron 12 1 (0.5%) Gly -~ Arg at 628 Exon 13 1 (0.5%) Frameshift Exon 13 2 (1.0%) Glu --~ Stop at 730 Exon 13 1 (0.5%) Frameshift Exon 14a I (0.5%) Gly --~ Arg at 970 Exon 15 1 (0.5%) 5' splice signal? Login to comment

[hide] A novel mutation in exon 3 of the CFTR gene. Hum Genet. 1993 Apr;91(3):233-5. Guillermit H, Jehanne M, Quere I, Audrezet MP, Mercier B, Ferec C
A novel mutation in exon 3 of the CFTR gene.
Hum Genet. 1993 Apr;91(3):233-5., [PMID:7682984]

Abstract [show]
We have screened the 27 exons of the cystic fibrosis transmembrane conductance regulator gene in 87 non-delta F508 chromosomes of Breton origin using the combined techniques of denaturing gradient gel electrophoresis and direct sequencing. By this process, we have detected a new missense mutation, G91R, which results in an arginine for glycine at codon 91. Three affected patients with a delta F508/G91R genotype are pancreatic sufficient. Such observations could facilitate a better understanding of the functional importance of different regions of the encoded product and of the pathogenesis of the disease.

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63 Other missense mutations reported by Kristidis et al. (1991) as being located in the transmembrane domain, i.e. R117H (exon 4), R334W (exon 7), R347P (exon 7), A455E (exon 9) and P574H (exon 12), are associated with pancreatic sufficiency; these observations are consistent with the genetic hypothesis that pancreatic sufficiency is a 235 dominant phenotypic trait associated with about 10% of the CF alleles. Login to comment

[hide] Genetic determinants of airways' colonisation with... Lancet. 1993 Jan 23;341(8839):189-93. Kubesch P, Dork T, Wulbrand U, Kalin N, Neumann T, Wulf B, Geerlings H, Weissbrodt H, von der Hardt H, Tummler B
Genetic determinants of airways' colonisation with Pseudomonas aeruginosa in cystic fibrosis.
Lancet. 1993 Jan 23;341(8839):189-93., [PMID:7678316]

Abstract [show]
Exocrine pancreatic insufficiency and lung infection with Pseudomonas aeruginosa are major features of cystic fibrosis (CF). This monogenic disease is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. 267 children and adolescents with CF who were regularly seen at the same centre were assessed for an association of the CFTR mutation genotype with exocrine pancreatic function and the age of onset of chronic colonisation with P aeruginosa. The major mutation delta F508 accounted for 74% of CF alleles; 33 further CFTR mutations had been detected on the CF chromosomes of the study population by June, 1992. With the exception of delta F508/R347P compound heterozygotes, patients of the same mutation genotype were either pancreas insufficient (PI) or pancreas sufficient (PS). The age-specific colonisation rates with P aeruginosa were significantly lower in PS than in PI patients. The missense and splice site mutations that are "mild" CF alleles with respect to exocrine pancreatic function were also "low risk" alleles for the acquisition of P aeruginosa. On the other hand, the proportion of P aeruginosa-positive patients increased most rapidly in the PI delta F508 compound heterozygotes who were carrying a termination mutation in the nucleotide binding fold-encoding exons. Pancreatic status and the risk of chronic airways' colonisation with P aeruginosa are predisposed by the CFTR mutation genotype and can be differentiated by the type and location of the mutations in the CFTR gene.

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90 The association between exocrine pancreatic function and genotypematched for 11 genotypes, the exception being the DgrF508/A455E compound heterozygotes (Hannover 1PI, Toronto 2PS). Login to comment

[hide] Cystic fibrosis genotypes and views on screening a... Am J Hum Genet. 1992 Nov;51(5):943-50. Scriver CR, Fujiwara TM
Cystic fibrosis genotypes and views on screening are both heterogeneous and population related.
Am J Hum Genet. 1992 Nov;51(5):943-50., [PMID:1384327]

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78 Ten alleles at 0.27% each .................... Total ............................................ French Canadians from northeastern Quebec (Rozen et al. 1992 [181]): 48 30 12 4 3 97 60 22 4 0 4 92a 82 4 1 1 1 2 3 98a AFS08 ......... ..................... 58 621+1G-T .............................. 23 A455E .......... .................... 8 G85E ......... ..................... 1 711+1 G-T ............................... 1 G542X .......... .................... 1 Y1092X .............................. 1 N1303K ........... ................... 1 Total .......... .................... 93a a Because of rounding, individual values do not sum to the total. Login to comment

[hide] The spectrum of CFTR mutations in south-west Germa... Hum Genet. 1992 Nov;90(3):267-9. Lindner M, Wolf A, Moh B, Steinbach P, Kleihauer E, Bartram CR, Kulozik AE
The spectrum of CFTR mutations in south-west German cystic fibrosis patients.
Hum Genet. 1992 Nov;90(3):267-9., [PMID:1283148]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) gene of 110 cystic fibrosis (CF) patients from the south-west of Germany was screened for 12 different mutations. This analysis resulted in an identification of 79% of all CF mutations and a complete genotype in 66% of the families. The most common mutation found was delta F508 (67%). Another 5 mutations accounted for a further 12.5% (4% G542X; 3% R553X; 3% N1303K; 2% 1717-1 G-->A; 0.5% G551D) whereas 6 mutations (R117H, A455E, delta I507, S549I, S549N, and R1162X) were not found. Fifty-four (49%) patients were delta F508 homozygotes and 18 (16.5%) were compound heterozygotes for delta F508 and one of the rarer mutations. These frequencies differ slightly from those found in the north of Germany and considerably from those reported from the south of Europe, which seems to be consistent with a north to south decline of the relative abundance of delta F508. Two patients, age 6 and 25 years, were compound heterozygotes for G542X and N1303K. The clinical features of the 6 year old were characterised by severe gastrointestinal and as yet only mild pulmonary complications whereas the 25 year old manifested severe pulmonary and gastrointestinal symptoms indicating that the N1303K mutation of the C-terminal CFTR nucleotide binding fold significantly impairs protein function in both the pancreas and the lungs.

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4 Another 5 mutations accounted for a further 12.5% (4% G542X; 3% R553X; 3% N1303K; 2% 1717-1 G--~A; 0.5% G551D) whereas 6 mutations (R117H, A455E, AI507, $549I, $549N, and R1162X) were not found. Login to comment
26 The R117H, A455E, 1717-1G~A, AF508, G542X, G551D, and NI303K mutations were identified by allele specific oligonucleotide hybridisation (ASO, Sambrook et al. 1989) using 32p-labelled probes specific for the normal or the mutated sequence (Table 1). Login to comment
34 Mutations observed in 220 defective cystic fibrosis transmembrane conductance regulator (CFTR) alleles Mutation n (%) Rll7H 0 A455E 0 AI507 0 AF508 147 (67) 1717-1G--*A 4 (2) G542X 9 (4) $549I 0 $549N 0 G551D 1 (<0.5) R553X 7 (3) R1162X 0 N1303K 6 (3) Unknown 46 (21) Total 220 (100) patients in that group R553X was considerably more common than G542X (Plieth et al. 1992). Login to comment
48 We are grateful to Professor Kubanek for his continuous support, to Professor Kaiser, Pforzheim for sending blood samples and providing clinical information on some of his patients, and to Dr.M. Schwarz, Royal Manchester Children's Hospital, for providing allele specific oligonucleotides for the R117H, A455E and 1717-1G--~A mutations together with the appropriate controls. Login to comment

[hide] The spectrum of cystic fibrosis mutations. Trends Genet. 1992 Nov;8(11):392-8. Tsui LC
The spectrum of cystic fibrosis mutations.
Trends Genet. 1992 Nov;8(11):392-8., [PMID:1279852]

Abstract [show]
Although the major mutation causing cystic fibrosis accounts for almost 70% of mutant chromosomes screened, almost 300 sequence alterations have been identified in the gene during the past two and a half years. At least 230 of these mutations are probably associated with disease. This rapid accumulation of data is in part due to the highly coordinated effort by members of the Cystic Fibrosis Genetic Analysis Consortium. The information is not only essential to genetic diagnosis, but also will aid in understanding the structure and function of the protein, and possibly in correlating genotype with phenotype.

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64 Frequent cystic fibrosis mutations Name Relative freqeenc~ Mutation Con~,~'~luence Ref. Z~508 67.2 G542X 3.4 G551D 2.4 W1282X 2.1 3905insT 2.1 N1303K 1.8 3849+10kbC-+T 1.4 1717-1G-+A 1078delT 2789+5G--+A Deletion of 3 bp between nt 1652 and t655 in exon 10 G-+T at nt 1756 in exon 11 G-+A at nt 1784 in exon 1I G-+A at nt 3978 in exon 20 Insertion of T after nt 3905 in exon 20 C-+G at nt 4041 in exon 21 C-->T in a 6.2 kb EcoRI fragment 10 kb from 5' junction of intron 19 3849+4A-+G 1.0 7tt÷IG--+T 0.9 Rl162X 0.9 1898+lG-+A 0.9 Rll7H 0.8 3659delc 0.8 G85E 0.7 2184delA 0.7 AI5W 0.5 R347P 0.5 R~ 0.4 1,3 C-+T at nt 1"789in exon 11 1.3 G-+T at nt 1 from 5' junction of intron 4 1.1 G--+A at nt 1 from 3' junction of intron 10 1.1 Deletion of T at nt 1078 in exon 7 1.1 G-cA at 5 nt from 5' end of intron 14b A-->G at 4 nt from 5' end of intron 19 G-+T at nt 1 from 5' junction of intron 5 C-+T at nt 3616 in exon 19 G-+A at nt 1 from 5' junction of intron 12 G--)A at nt 482 in exon Deletion of C at nt 3659 in exon 19 G-+A at nt 386 in exon 3 A-->G at nt 2183 and deletion of A at nt 2184 in exon 13 Deletion of 3 bp between nt 1648 and 1653 in exon 10 G-+C at nt 1172 in exon 7 G-~C at nt 1811 in exon 11 A455E 0.4 R334W 0.4 Y122X 0.3 S549R(T-+G) 0.3 Q493X 0.3 V520F 0.2 S549N 0.2 C-+A at nt 1496 in exon 9 C-+T at nt 1132 in exon 7 T-cA at nt ~i98 in exon 4 T--+G at nt 1779 in exon 11 C-+T at nt 1609 in exon 10 G-+T at nt 1690 in exon 10 G-->A at nt I778 in exon !1 Deletion of Phe at codon 508 Gly-+Stop at codon 542 12 Gly-~Asp at codon 551 10 l"rp-->Stop at codon t282 35 Frameshift -~ Asn-+Lys at codon 1303 36 Aberrant splicing -~ Arg~Stop ~ codon 553 Splice mutation 10 37 Splice mutation 12 Frameshift 38 Splice mutation _c Splice mutation? Login to comment
122 This hypothesis has been well supported by analysis of patients, which shows that individuals with one or two copies of the missense alleles such as Rll7H, R334W, R347P, A455E (Ref. 12) or P574H (Ref. 12) are found to be PS, whereas those with two copies of nonsense, frameshift, splice-site or a subset of the missense mutations are invariably PI TIGNOVEMBER1992 VOt. Login to comment

[hide] Milestones in cystic fibrosis. Br Med Bull. 1992 Oct;48(4):717-37. Super M
Milestones in cystic fibrosis.
Br Med Bull. 1992 Oct;48(4):717-37., [PMID:1281032]

Abstract [show]
The study of cystic fibrosis (CF) provides a fascinating insight into developments in medicine in the 20th century. Milestones include the first clear clinical descriptions in the 1930s, discovery of a sweat electrolyte abnormality, establishing the autosomal recessive mode of inheritance and improvements in treatment. Microdissection experiments on sweat glands allowed the main defect to be delineated as one of chloride transport. Location of the gene to chromosome 7 made prenatal diagnosis feasible and carrier detection in siblings. The CF gene--its product being the cystic fibrosis transmembrane conductance regulator (CFTR), and its major mutation Delta F508 was discovered in 1989. World-wide collaboration has resulted in discovery of more than 150 further mutations. Incorporation of CFTR into non-chloride transporting insect cells by conferring chloride transport, proved it a chloride channel. CFTR incorporated into adenovirus results in correction of the chloride transport defect in airway cells, bringing gene therapy closer.

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164 Mutations encountered elsewhere in UK but not yet m N-W 1154insTC R347P A455E G458V Q493X C524X S549N R1283M Q1291H 199 (in the north-west group) 199 199 0 0 0 199 199 0 icant alteration in function appears to be worse than no CFTR being formed at all. Login to comment

[hide] Regulation of cystic fibrosis transmembrane conduc... J Biol Chem. 1992 Sep 25;267(27):19299-305. Montrose-Rafizadeh C, Blackmon DL, Hamosh A, Oliva MM, Hawkins AL, Curristin SM, Griffin CA, Yang VW, Guggino WB, Cutting GR, et al.
Regulation of cystic fibrosis transmembrane conductance regulator (CFTR) gene transcription and alternative RNA splicing in a model of developing intestinal epithelium.
J Biol Chem. 1992 Sep 25;267(27):19299-305., [PMID:1382071]

Abstract [show]
Transcriptional and post-transcriptional regulation of CFTR (cystic fibrosis transmembrane conductance regulator) gene expression was studied in HT29 cells. It is known that the abundance of CFTR mRNA increases during differentiation of pluripotent HT29-18 cells and is maintained at high levels in the stably differentiated HT29-18-C1 subclone. Nuclear run-on assays suggest that increased transcription of the CFTR gene explains the increased abundance of total CFTR mRNA in differentiated HT29 cells. The increased transcription cannot be ascribed to cell cycle-dependent expression of the CFTR gene or to changes in CFTR gene copy number between subcloned cells. Similar to native tissue cells, differentiated HT29 cells contain low copy numbers of CFTR transcripts (1-5/cell), and a portion of the CFTR transcripts are alternatively spliced to remove exon 9 (and make 9-mRNA). During differentiation of HT29-18 cells, the absolute amount of full-length CFTR mRNA increases 8-fold, whereas the amount of 9- mRNA increases 18-fold. The fraction of 9- mRNA in the CFTR mRNA pool is increased in differentiated HT29 cells. The results show that gene transcription regulates the abundance of CFTR transcripts and that regulatory control of alternative RNA splicing may also be a cellular mechanism to modulate CFTR function.

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194 Furthermore, exon9 is the site of twomissense mutations known to causeclinical CF (A455E and G458V), emphasizing the functional importanceof this portionof NBFl (41,42). Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... FASEB J. 1992 Jul;6(10):2775-82. McIntosh I, Cutting GR
Cystic fibrosis transmembrane conductance regulator and the etiology and pathogenesis of cystic fibrosis.
FASEB J. 1992 Jul;6(10):2775-82., [PMID:1378801]

Abstract [show]
Cystic fibrosis (CF) is an inherited disorder causing pancreatic, pulmonary, and sinus disease in children and young adults. Abnormal viscosity of mucous secretions is a hallmark of the disease, and is believed to be the result of altered electrolyte transport across epithelial cell membranes. The monogenic etiology of this disease has been apparent for more than 40 years, but the defective gene has only recently been identified. This was made possible because of a revolution in genetic technology, called positional cloning, which can pinpoint disease genes without previous knowledge of the abnormal protein product. The protein encoded by the gene defective in CF has been termed the CF transmembrane conductance regulator (CFTR) because of its postulated role in electrolyte transport. Studies investigating the normal function of CFTR and how mutations affect that function, thereby causing CF, have required the combined skills of clinicians, geneticists, molecular biologists, and physiologists. From this collaborative effort a greater understanding of the pathogenesis of this disorder is now emerging. It may soon be possible to introduce novel therapies derived from this new knowledge that will be aimed directly at the basic defect. An ever-increasing number of genes of unknown function will be identified by continuing advances in molecular genetic technology and the advent of the genome sequencing project. The experience in cystic fibrosis research may prove to be a paradigm for investigation of the function of genes isolated by positional cloning methods.

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109 CF mutations that occur at a frequency of 5% or greater in certain population groups Region Mutation Population group Frequency Reference Transmembrane 1-6 621 + 1GT 711+1GT French Canadian; Saguenay-Lac St. Jean French Canadian; Urban Quebec 0.23 0.09 72 72 NBF 1 A455E SF508 G542X G551D French Canadian; Saguenay-Lac St. Jean Worldwide Ashkenazi Jewish Spanish Scottish 0.08 0.30-0.88 0.12 0.05 0.05 72 14 73 74 75 Transmembrane 7-12 R1162X N.E. Italian 0.05 74 NBF 2 W1282X Ashkenazi Jewish 0.48 56, 73 press CFTR and in those used for transient expression studies (33). Login to comment

[hide] Analysis of four diverse population groups indicat... Am J Hum Genet. 1992 Jun;50(6):1185-94. Cutting GR, Curristin SM, Nash E, Rosenstein BJ, Lerer I, Abeliovich D, Hill A, Graham C
Analysis of four diverse population groups indicates that a subset of cystic fibrosis mutations occur in common among Caucasians.
Am J Hum Genet. 1992 Jun;50(6):1185-94., [PMID:1376017]

Abstract [show]
To determine the nature and frequency of non-delta F508 cystic fibrosis (CF) mutations among diverse populations, we have sequenced exons 9-12 and 19-23 of the CF transmembrane conductance regulator (CFTR) gene from 128 CF chromosomes (39 U.S. Caucasian, 27 African-American, 42 Northern Irish, and 20 Israeli chromosomes). These regions were chosen because they encode the two putative ATP-binding folds of CFTR, domains which appear to have functional significance. In addition, CFTR exons 1 and 2 were analyzed in the American patients. Mutations were found on 49 of the 128 CF chromosomes. Nineteen different mutations were observed; six were novel, while the remaining 13 had been reported previously by our group or by other investigators. Six of nine different mutations found in African-American patients were unique to that population. However, the vast majority of the mutations found in U.S. Caucasians (eight of nine), Northern Irish (four of five), and Israelis (three of three) also occurred in other Caucasian groups. The preponderance of previously reported mutations in these three groups suggested that a subset of the non-delta F508 mutations occur in common among Caucasians. A survey of mutation frequencies in other Caucasian groups confirmed this observation. Unfortunately, this subset accounts for less than half of non-delta F508 CF mutations in most groups. These data suggest that screening for delta F508 and this select group of mutations will efficiently and economically maximize the number of CF mutations identified in Caucasian groups. However, it will be difficult to detect more than 90% of mutant CFTR alleles except in ethnically and geographically discrete populations where CF is the result of founder effect.

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148 This phenomenon also appears to account for the high frequency of mutations 621 + 1G-*T and A455E observed in French-Canadian families from the Saguenay-Lac St. Jean region ofQuebec (Rozen et al. 1992). Login to comment

[hide] Genetic determination of exocrine pancreatic funct... Am J Hum Genet. 1992 Jun;50(6):1178-84. Kristidis P, Bozon D, Corey M, Markiewicz D, Rommens J, Tsui LC, Durie P
Genetic determination of exocrine pancreatic function in cystic fibrosis.
Am J Hum Genet. 1992 Jun;50(6):1178-84., [PMID:1376016]

Abstract [show]
We showed elsewhere that the pancreatic function status of cystic fibrosis (CF) patients could be correlated to mutations in the CF transmembrane conductance regulator (CFTR) gene. Although the majority of CF mutations--including the most common, delta F508--strongly correlated with pancreatic insufficiency (PI), approximately 10% of the mutant alleles may confer pancreatic sufficiency (PS). To extend this observation, genomic DNA of 538 CF patients with well-documented pancreatic function status were analyzed for a series of known mutations in their CFTR genes. Only 20 of the 25 mutations tested were found in this population. They accounted for 84% of the CF chromosomes, with delta F508 being the most frequent (71%), and the other mutations accounted for less than 5% each. A total of 30 different, complete genotypes could be determined in 394 (73%) of the patients. The data showed that each genotype was associated only with PI or only with PS, but not with both. This result is thus consistent with the hypothesis that PI and PS in CF are predisposed by the genotype at the CFTR locus; the PS phenotype occurs in patients who have one or two mild CFTR mutations, such as R117H, R334W, R347P, A455E, and P574H, whereas the PI phenotype occurs in patients with two severe alleles, such as delta F508, delta I507, Q493X, G542X, R553X, W1282X, 621 + 1G----T, 1717-1G----A, 556delA, 3659delC, I148T, G480C, V520F, G551D, and R560T.

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10 This result is thus consistent with the hypothesis that PI and PS in CF are predisposed by the genotype at the CFTR locus; the PS phenotype occurs in patients who have one or two mild CFTR mutations, such as R117H, R334W, R347P, A455E, and P574H, whereas the PI phenotype occurs in patients with two severe alleles, such as AF508, A1507, Q493X, G542X, R553X, W1282X, 621 + 1G-PT, 1717-1G--'A, 556delA, 3659delC, I148T, G480C, V520F, G551D, and R560T. Login to comment
57 Intron 4: 621 + 1G-T Exon 7: R334W ......... R347P ........... Exon 9: A455E .......... G458V .......... G480C .......... Exon 10: Q493X .......... A1507 ........... AF508 .......... VS2OF .......... Login to comment
66 As shown in table 3, meconium ileus Table 2 1181 Table 3 Frequency of 25 CF Mutations in Chromosomes of the Toronto Study Population Mutation AF508 ...... G551D...... G542X...... 621 +1G-'T N1303K..... W1282X..... R1 17H...... 1717-1G-~A R560T...... A1507 ...... R553X...... V52OF ...... R334W ..... A455E...... I148T ...... Q493X...... P574H...... R347P ...... SS6delA ..... 3659delC .... G480C...... 444delA ..... D110H...... G458V...... S549R ...... Y563N...... Login to comment
81 Table 4 Classification of CF Gene Mutations as Severe or Mild with Respect to Pancreatic Function Type of Mutation Severe (location) Mild (location) Missense (point mutation) ...... 1148T (exon 4) R117H (exon 4) G480C (exon 9) R334W (exon 7) VS2OF (exon 10) GSS1D (exon 11) R347P (exon 7) RS60T (exon 11) A455E (exon 9) N1303K (exon 21) P574H (exon 12) Single amino acid deletion ........ AFS08 (exon 10) A1507 (exon 10) Stop codon (nonsense) ..... Q493X (exon 10) G542X (exon 11) R553X (exon 11) W1282X (exon 20) Splice junction ... 621 + 1G-T (intron 4) 1717-1G-T (intron 10) Frameshift ........ 556delA (exon 4) 3659delC (exon 19) with any of the mild mutations was associated with PS. Login to comment
85 Accordingly, the mutations R117H, R334W, R347P, A455E, and P574H may be regarded as mild, whereas AF508, AI507, Q493X, G542X, R553X, W1282X, 621 + 1G-T, 1717-1G--A, 556delA, 3659delC, 1148T, G480C, V520F, GSS1D, and R560T are severe. Login to comment

[hide] Identification and developmental expression of the... Hum Mol Genet. 1992 May;1(2):77-82. Tucker SJ, Tannahill D, Higgins CF
Identification and developmental expression of the Xenopus laevis cystic fibrosis transmembrane conductance regulator gene.
Hum Mol Genet. 1992 May;1(2):77-82., [PMID:1284470]

Abstract [show]
An amphibian homologue of the human cystic fibrosis transmembrane conductance regulator (CFTR) gene has been isolated from Xenopus laevis by polymerase chain reaction (PCR) amplification. The 4455bp sequence encodes a predicted polypeptide of 1485 amino acids which has an overall homology at the amino acid level of 77% identity and 88% similarity with human CFTR. Comparison of these evolutionarily diverse CFTR sequences has structure-function implications. Investigation of the expression of the Xenopus gene during early stages of development (Stages 1-48), using RNAase protection assays and PCR analysis of total Xenopus RNA, shows CFTR mRNA to be present at the very earliest stages of development, including the oocyte and blastula stages, with increasing amounts during subsequent development. The identification of mRNA for a CFTR homologue in the Xenopus oocyte and early stages of development has implications for its biological role.

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115 Other missense mutations implicated in the disease, A455E and G458V (25)(26), also show conservation at these positions, supporting the view that they are functionally important. Login to comment

[hide] Intra- and extragenic marker haplotypes of CFTR mu... Hum Genet. 1992 Feb;88(4):417-25. Dork T, Neumann T, Wulbrand U, Wulf B, Kalin N, Maass G, Krawczak M, Guillermit H, Ferec C, Horn G, et al.
Intra- and extragenic marker haplotypes of CFTR mutations in cystic fibrosis families.
Hum Genet. 1992 Feb;88(4):417-25., [PMID:1371263]

Abstract [show]
In order to facilitate the screening for the less common mutations in the cystic fibrosis (CF) gene viz., the CF transmembrane conductance regulator gene (CFTR), marker haplotypes were determined for German non-CF (N) and CF chromosomes by polymerase chain reaction analysis of four polymorphisms upstream of the CF gene (XV-2c, KM.19, MP6-D9, J44) and six intragenic polymorphisms (GATT, TUB9, M470V, T854T, TUB18, TUB20) that span the CFTR gene from exon 6 through exon 21. Novel informative sequence variants of CFTR were detected in front of exons 10 (1525-61 A or G), 19 (3601-65 C or A), and 21 (4006-200 A or G). The CF locus exhibits strong long-range marker-marker linkage disequilibrium with breakpoints of recombination between XV-2c and KM.19, and between exons 10 and 19 of CFTR. Marker alleles of GATT-TUB9 and TUB18-TUB20 were found to be in absolute linkage disequilibrium. Four major haplotypes encompass more than 90% of German N and CF chromosomes. Fifteen CFTR mutations detected on 421 out of 500 CF chromosomes were each identified on one of these four predominant 7-marker haplotypes. Whereas all analysed delta F508 chromosomes carried the same KM.19-D9-J44-GATT-TUB9-M470V-T854T haplotype, another frequent mutation in Germany, R553X, was identified on two different major haplotypes. Hence, a priori haplotyping cannot exclude a particular CF mutation, but in combination with population genetic data, enables mutations to be ranked by decreasing probability.

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25 Most CFTR mutations were investigated by restriction analysis of PCR products (R334W, R347P, A455E, G551D, R553X, 2789+5 G---~A,Rl162X, W1282X) (Cutting et al. 1990; Dean et al. 1990b; Gasparini et al. 1991b; Highsmith et al. 1990; Kerem et al. 1990;Vidaud et al. 1990) (see Table 4). Login to comment
98 ASO, Allele-specificoligonucleotide hybridization; TGGE, temperature gradient gel electrophoresis; SSCP, single strand conformation polymorphism Mutation Localization No. % Method of detectiona Reference R117H Exon 4 2 0.4 ASO Dean et al. (1990b) R334W Exon 7 2 0.4 RFLP MspI Gasparini et al. (1991b) R347P Exon 7 5 1.0 RFLP NcoI Dean et al. (1990b) A455E Exon 9 1 0.2 RFLP AciI Kerem et al. (1990) F508C2 Exon 10 1 0.2 Nondenaturing PAGE Kobayashi et al. (1990) AF508 Exon 10 370 74.0 Nondenaturing PAGE Kerem et al. (1989) 1717-1 G---~A Intron 10 2 0.4 TGGE Kerem et al. (1990) G542X Exon 11 5 1.0 Allele-specificPCR Kerem et al. (1990) G551D Exon 11 5 1.0 RFLP DpnII Cutting et al. (1990) R553X Exon 11 12 2.4 RFLP HincII Cutting et al. (1990) 2789 + 5 G---~A Intron 14B 3 0.6 RFLP SspI Highsmith et al. (1990) Rl162X Exon 19 1 0.2 RFLP DdeI Gasparini et al. (1991b) 3659delC Exon 19 3 0.6 SSCP Kerem et al. (1990) W1282X Exon 20 2 0.4 RFLP MnlI Vidaud et al. (1990) N1303K Exon 21 7 1.4 Allele-specificPCR Osborne et al. (1991) Unpublished 13 2.6 Unknown 66 13.2 Total 500 a All non-AF508 mutations were subsequently verified by direct genomic sequencing of the respective PCR product b F508C was first detected on an N chromosome (Kobayashi et al. 1990) and hence is suspected to represent a benign missense mutation Table 5. Login to comment
100 The four major haplotypes are indicated in bold type KM.19 D9 J44 GATT TUB9 M470V T854T TUB18 TUB20 Mutation 1 l 2 1 2 2 1 1 2 2 2 1 1 2 1 2 2 1 2 2 1 1 2 1 2 1 2 2 2 1 2 1 1 1 1 2 2 2 1 2 1 1 1 2 i 1 2 1 2 1 1 2 1 2 R347P, F508C, R1162X, 3659delC 1717-1 G--~A, G551D, R553X (n = 2), 2789 + 5 G---~A,W1282X R117H R334W, A455E, G542X, N1303K, AF508 (96%) ~F508 (4%) R553X (n = 10) a Haplotypes were assigned from the individual pedigrees mutation was located on a single KM. 19-D9-J44-GATT-TUB9-M470V-T854T haplotype. Login to comment
106 Several more frequent disease-causing sequence variations, such as R334W, A455E, G542X, and N1303K, reside on the typical AF508 haplotype. Login to comment
134 1) A455E, G551D, 3659delC, W1282X, and N1303K were first detected on chromosomes of Anglo-Saxon or French origin (Cutting et al. 1990; Kerem et al. 1990; Vidaud et al. 1990; Osborne et al. 1991). Login to comment

[hide] Effects of cystic fibrosis and congenital bilatera... Am J Hum Genet. 2000 May;66(5):1485-95. Epub 2000 Apr 4. Mickle JE, Milewski MI, Macek M Jr, Cutting GR
Effects of cystic fibrosis and congenital bilateral absence of the vas deferens-associated mutations on cystic fibrosis transmembrane conductance regulator-mediated regulation of separate channels.
Am J Hum Genet. 2000 May;66(5):1485-95. Epub 2000 Apr 4., [PMID:10762539]

Abstract [show]
The protein defective in cystic fibrosis (CF), the CF transmembrane-conductance regulator (CFTR), functions as an epithelial chloride channel and as a regulator of separate ion channels. Although the consequences that disease-causing mutations have on the chloride-channel function have been studied extensively, little is known about the effects that mutations have on the regulatory function. To address this issue, we transiently expressed CFTR-bearing mutations associated with CF or its milder phenotype, congenital bilateral absence of the vas deferens, and determined whether mutant CFTR could regulate outwardly rectifying chloride channels (ORCCs). CFTR bearing a CF-associated mutation in the first nucleotide-binding domain (NBD1), DeltaF508, functioned as a chloride channel but did not regulate ORCCs. However, CFTR bearing disease-associated mutations in other domains retained both functions, regardless of the associated phenotype. Thus, a relationship between loss of CFTR regulatory function and disease severity is evident for NBD1, a region of CFTR that appears important for regulation of separate channels.

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37 Specifically, two missense mutations in NBF1 have been evaluated: A455E, which is associated with mild lung disease, and G551D, which is associated with a more severe pulmonary phenotype (Hamosh et al. 1992; Gan et al. 1995). Login to comment
38 CFTR bearing A455E retains both CFTR Cl2 channel activity and the ability to regulate ORCCs (Fulmer et al. 1995). Login to comment
47 DNA was assayed for 16 common CFTR mutations (R117H, 62111GrT, R334W, R349P, A455E, DI507, DF508, 1717-1GrA, G542X, S549N, G551D, R553X, R560T, 3849110 Kb CrT, W1282X, and N1303K), by reverse dot-blot hybridization (Mickle et al. 1998). Login to comment
182 d Data for A455E and G551D have been reported elsewhere (Fulmer et al. 1995). Login to comment

[hide] Pancreatic function and extended mutation analysis... J Pediatr. 2000 Aug;137(2):214-20. Massie RJ, Wilcken B, Van Asperen P, Dorney S, Gruca M, Wiley V, Gaskin K
Pancreatic function and extended mutation analysis in DeltaF508 heterozygous infants with an elevated immunoreactive trypsinogen but normal sweat electrolyte levels.
J Pediatr. 2000 Aug;137(2):214-20., [PMID:10931414]

Abstract [show]
BACKGROUND: Newborn screening for cystic fibrosis (CF) with immunoreactive trypsinogen (IRT) and DeltaF508 analysis followed by sweat testing misses some infants with CF and detects more DeltaF508 carriers than expected. Some of the apparent DeltaF508 carriers may be DeltaF508 compound heterozygotes with normal sweat electrolyte levels. METHODS: Infants identified by newborn screening with an elevated IRT level, one DeltaF508 allele, and a sweat chloride level <60 mmol/L underwent CF mutation analysis, pancreatic stimulation testing, and repeat IRT analysis followed by clinical review and repeat sweat test at 12 months. RESULTS: Over a 24-month period we identified 122 DeltaF508 heterozygotes and recruited 57; 4 had borderline sweat chloride levels (40 to 60 mmol/L), 5 (8.8%, 95% CI 1.4, 16.2) had a second CF mutation (R117H), and 11 (20%, 95% CI 10, 30) had the intron 8 5T allele. Three had clinical CF at 12 months (initial sweat chloride levels: 53, 51, and 32 mmol/L). Pancreatic electrolyte secretion in the subjects with a borderline sweat chloride level was similar to that in patients with known CF. CONCLUSION: The excess of DeltaF508 heterozygotes detected by IRT/DNA screening is associated with the presence of a second mutation or the 5T allele in some infants. Screened infants with borderline sweat chloride levels almost certainly have CF, but long-term follow-up of the infants with the genotype DeltaF508/R117H and DeltaF508/5T is required to determine their outcome. In the meantime, newborn screening should be confined to severe mutations associated with classic CF.

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26 Measurement of Cl levels was done by colorimetry, and measurement of sodium levels was done by flame cytometry.16 Gene Mutation Analysis Blood was taken and DNA extract- ed17 for an extended cystic fibrosis transmembrane conductance regulator protein gene mutation analysis as described previously.18 The following mutations were included: ࢞F508, ࢞I507, R117H, G551D, A455E, G542X, N1303K, W1282X, 1717-1G࢐A, R560T, R347P, R334W, R553X, R1162X, S549N, 3849+10C࢐T, and 621+1G࢐T. Login to comment

[hide] Analysis of 31 CFTR mutations in 55 families from ... Early Hum Dev. 2001 Nov;65 Suppl:S161-4. Gomez-Llorente MA, Suarez A, Gomez-Llorente C, Munoz A, Arauzo M, Antunez A, Navarro M, Gil A, Gomez-Capilla JA
Analysis of 31 CFTR mutations in 55 families from the South of Spain.
Early Hum Dev. 2001 Nov;65 Suppl:S161-4., [PMID:11755047]

Abstract [show]
We carried out a molecular analysis of 350 chromosomes from 55 families originating from the South of Spain (Andalucia) who were diagnosed with cystic fibrosis (CF). We used polymerase chain reaction, followed by an oligonucleotide ligation assay (OLA) and sequence-coded separation using capillary electrophoresis. A frequency of 43.5% for DeltaF508 was found, making it the most common CF mutation in our sample. Seven more mutations (G542X, R334W, R1162X, 2789+5G-->A, R117H, DeltaI507 and W1282X) were detected and accounted for 24.7% of the total. The remaining mutations (31.8%) were undetectable with the methodology used in this study.

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31 T I.19 A455E E.9 3849 + 4A ! Login to comment

[hide] Gentamicin in pharmacogenetic approach to treatmen... Lancet. 2001 Dec 15;358(9298):2014-6. Hamilton JW
Gentamicin in pharmacogenetic approach to treatment of cystic fibrosis.
Lancet. 2001 Dec 15;358(9298):2014-6., [PMID:11755605]

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75 THE LANCET ߦ Vol 358 ߦ December 15, 2001 2015 COMMENTARY Effect of CFTR mutations in epithelial cells Lumen Cytoplasm Nucleus Class 4 (eg, R117H) Class 3 (eg, G551D) Class 2 (eg, èc;F508) Class 1 (eg, G542X) Class 5 (eg, A455E) Apical surface Basolateral surface ATP CFTR MSD NBD NBD RD Golgi ER CFTR gene Collectively, the five mutant classes result in little or no functional CFTR expression at the apical surface of epithelial cells, but through different mechanisms. Login to comment
81 Class 5 mutations (such as A455E) reduce synthesis by impairing transcription, causing alternative splicing of mRNA, or causing aminoacid substitutions that alter early steps in protein biogenesis. Login to comment

[hide] Effect of genotype on phenotype and mortality in c... Lancet. 2003 May 17;361(9370):1671-6. McKone EF, Emerson SS, Edwards KL, Aitken ML
Effect of genotype on phenotype and mortality in cystic fibrosis: a retrospective cohort study.
Lancet. 2003 May 17;361(9370):1671-6., [PMID:12767731]

Abstract [show]
BACKGROUND: Over 1000 mutations of the cystic fibrosis transmembrane conductance regulator gene (CFTR) that cause cystic fibrosis have been identified. We examined the effect of CFTR genotype on mortality and disease phenotype. METHODS: Using the US Cystic Fibrosis Foundation National Registry, we did a retrospective cohort study to compare standardised mortality rates for the 11 most common genotypes heterozygous for DeltaF508 with those homozygous for DeltaF508. Of the 28455 patients enrolled in the registry at the time of our analysis, 17853 (63%) were genotyped. We also compared the clinical phenotype, including lung function, age at diagnosis, and nutritional measures, of 22 DeltaF508 heterozygous genotypes. Mortality rates and clinical phenotype were also compared between genotypes classified into six classes on the basis of their functional effect on CFTR production. FINDINGS: Between 1991 and 1999, genetic and clinical data were available for 17853 patients with cystic fibrosis, which was 63% of the total cohort. There were 1547 deaths during the 9 years of follow-up. In the analysis of the 11 most common genotypes, DeltaF508/R117H, DeltaF508/DeltaI507, DeltaF508/3849+10kbC-->T, and DeltaF508/2789+5G-->A had a significantly lower mortality rate (4.7, 8.0, 11.9, and 4.4, respectively) than the genotype homozygous for DeltaF508 (21.8, p=0.0060). DeltaF508/R117H, DeltaF508/DeltaI507, DeltaF508/ 3849+10 kbC-->T, DeltaF508/2789+5G-->A, and DeltaF508/A455E have a milder clinical phenotype. Outcomes for all functional classes were compared with that of class II (containing DeltaF508 homozygotes) and classes IV and V had a significantly lower mortality rate and milder clinical phenotype. INTERPRETATION: Patients with cystic fibrosis have distinct genetic subgroups that are associated with mild clinical manifestations and low mortality. These differences in phenotype are also related to the functional classification of CFTR genotype.

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9 èc;F508/R117H, èc;F508/èc;I507, èc;F508/ 3849+10 kbC࢐T, èc;F508/2789+5G࢐A, and èc;F508/A455E have a milder clinical phenotype. Login to comment
47 ARTICLES 1672 THE LANCET ߦ Vol 361 ߦ May 17, 2003 ߦ www.thelancet.com Panel 1: Frequencies of CFTR mutations* CFTR Allele CFTR Allele mutation frequency (%) mutation frequency èc;F508 69&#b7;4% 2789+5G࢐A 0&#b7;3% Unknown 15&#b7;7% R1162X 0&#b7;3% G542X 2&#b7;3% G85E 0&#b7;3% G551D 2&#b7;2% R560T 0&#b7;2% èc;I507 1&#b7;6% R334W 0&#b7;2% W1282X 1&#b7;4% 3659èc;C 0&#b7;2% N1303K 1&#b7;2% A455E 0&#b7;1% R553X 0&#b7;9% 711+1G࢐T 0&#b7;1% 621+1G࢐T 0&#b7;8% 1898+1G࢐A 0&#b7;1% R117H 0&#b7;7% 2184èc;A 0&#b7;1% 3849+10 kbC࢐T 0&#b7;7% S549N 0&#b7;1% 1717-IG࢐A 0&#b7;5% 1078èc;T 0&#b7;03% R347P 0&#b7;3% *n=17 853. Login to comment
48 Panel 2: Functional classification of CFTR alleles Class Functional effect of Allele mutation I Defective protein G542X, R553X, W1282X, production R1162X, 621-1G࢐T, 1717-1G࢐A, 1078èc;T, 3659èc;C II Defective protein èc;F508, èc;I507, N1303K, processing S549N III Defective protein G551D, R560T regulation IV Defective protein R117H, R334W, G85E, conductance R347P V Reduced amounts of 3849+10KbC࢐T, functioning CFTR protein 2789+5G࢐A, A455E Unknown 711+1G࢐T, 2184DA, 1898+1G࢐A Total cohort Genotyped cohort (n=28 455) (n=17 853) Person-years at risk 152 011 96 870 Sex (% male) 53% 52% Race (% white) 96% 96% Age (years) 11&#b7;9 (11&#b7;1) 10&#b7;9 (11&#b7;2) Age at diagnosis (years) 3&#b7;5 (7&#b7;1) 3&#b7;6 (7&#b7;5) Sweat test (mmol/L) 101 (19) 100 (20) FEV1 (L) 1&#b7;72 (0&#b7;91) 1&#b7;80 (0&#b7;92) FEV1 (% predicted) 69 (29) 72 (28) FVC (L) 2&#b7;41 (1&#b7;18) 2&#b7;50 (1&#b7;21) FVC (% predicted) 81% (28) 84% (24) Height (cm) 121% (41) 117% (41) Weight (kg) 30&#b7;0 (21&#b7;3) 28&#b7;6 (21&#b7;8) Pancreatic insufficiency (%) 90% 87% P aeruginosa colonisation (%) 49% 46% Number of deaths (%) 3548 (12%) 1547 (9%) Data are mean (SD) unless otherwise stated. Login to comment
67 Table 2: Standardised and crude mortality rates (including organ transplantation) by genotype Genotype No of Age at Sweat FEV1 FVC Height Weight Pancreatic P&#b7; aeruginosa Subjects Diagnosis Chloride (% predicted)* (% predicted)* (cms)* (kg)* Insufficiency Colonization (yrs) (mmol) (%)ߤ (%)ߤ èc;F508/èc;F508 6 213 2&#b7;5 &#b1; 0&#b7;1 104 &#b1; 0&#b7;2 77 &#b1; 0&#b7;3 89 &#b1; 0&#b7;3 141 &#b1; 0&#b7;2 37&#b7;0 &#b1; 0&#b7;1 92 (91-92) 60 (59-61) èc;F508/G551D 411 3&#b7;7 &#b1; 0&#b7;3ߥ 108 &#b1; 0&#b7;9ߥ 76 &#b1; 1&#b7;2 89 &#b1; 1&#b7;2 142 &#b1; 0&#b7;7&#a7; 38&#b7;2 &#b1; 0&#b7;6&#a7; 92 (89-94) 59 (54-64) èc;F508/G542X 389 1&#b7;9 &#b1; 0&#b7;2 104 &#b1; 0&#b7;8 79 &#b1; 1&#b7;2 91 &#b1; 1&#b7;2 141 &#b1; 0&#b7;7 37&#b7;3 &#b1; 0&#b7;5 93 (89-95) 57 (52-62) èc;F508/N1303K 213 2&#b7;1 &#b1; 0&#b7;3 106 &#b1; 1&#b7;2 80 &#b1; 1&#b7;8 91 &#b1; 1&#b7;7 141 &#b1; 1&#b7;0 37&#b7;1 &#b1; 0&#b7;6 92 (87-95) 61 (55--68) èc;F508/W1282X 205 1&#b7;6 &#b1; 0&#b7;2 103 &#b1; 1&#b7;2 80 &#b1; 1&#b7;7 92 &#b1; 1&#b7;6 141 &#b1; 0&#b7;9 37&#b7;4 &#b1; 0&#b7;7 94 (90-97) 59 (52-65) èc;F508/R553X 164 2&#b7;5 &#b1; 0&#b7;4 106 &#b1; 1&#b7;4 76 &#b1; 1&#b7;8 89 &#b1; 1&#b7;6 139 &#b1; 0&#b7;9 35&#b7;4 &#b1; 0&#b7;7&#a7; 90 (85-94) 60 (53-67) èc;F508/621-1G 162 2&#b7;5 &#b1; 0&#b7;4 107 &#b1; 1&#b7;3 78 &#b1; 1&#b7;8 89 &#b1; 1&#b7;5 143 &#b1; 1&#b7;0&#a7; 38&#b7;8 &#b1; 0&#b7;8&#a7; 87 (80-91)&#a7; 57 (49-64) èc;F508/èc;I507 149 8&#b7;5 &#b1; 1&#b7;1ߥ 95 &#b1; 1&#b7;9ߥ 86 &#b1; 2&#b7;1ߥ 93 &#b1; 1&#b7;8&#a7; 137 &#b1; 1&#b7;4&#a7; 37&#b7;4 &#b1; 1&#b7;25 84 (78-89)ߥ 39 (31-48)ߥ èc;F508/R117H 123 13&#b7;7 &#b1; 1&#b7;2ߥ 80 &#b1; 1&#b7;9ߥ 91 &#b1; 2&#b7;1ߥ 97 &#b1; 1&#b7;7ߥ 143 &#b1; 1&#b7;8 42&#b7;9 &#b1; 1&#b7;7ߥ 65 (55-73)ߥ 22 (16-29)ߥ èc;F508/3849+10 kB 114 11&#b7;3 &#b1; 0&#b7;9ߥ 72 &#b1; 2&#b7;5ߥ 77 &#b1; 2&#b7;1 87 &#b1; 1&#b7;9 144 &#b1; 1&#b7;4&#a7; 41&#b7;2 &#b1; 1&#b7;2ߥ 66 (57-74)ߥ 69 (59-77) èc;F508/2789+5G 63 13&#b7;4 &#b1; 1&#b7;6ߥ 102 &#b1; 2&#b7;1 88 &#b1; 2&#b7;8ߥ 97 &#b1; 2&#b7;3ߥ 140 &#b1; 2&#b7;5 41&#b7;8 &#b1; 2&#b7;2&#a7; 71 (59-81)ߥ 32 (22-44)ߥ èc;F508/1717-1G 74 1&#b7;3 &#b1; 0&#b7;3 103 &#b1; 2&#b7;0 75 &#b1; 2&#b7;7 86 &#b1; 2&#b7;4 139 &#b1; 1&#b7;5 35&#b7;7 &#b1; 0&#b7;9 96 (88-99) 59 (48-69) èc;F508/R560T 46 1&#b7;7 &#b1; 0&#b7;5 104 &#b1; 2&#b7;0 84 &#b1; 3&#b7;3ߥ 96&#b1; 2&#b7;8&#a7; 142 &#b1; 1&#b7;9 38&#b7;4 &#b1; 1&#b7;4 91 (79-97) 63 (48-75) èc;F508/R347P 44 5&#b7;9 &#b1; 1&#b7;1&#a7; 105 &#b1; 2&#b7;6 76 &#b1; 3&#b7;0 90 &#b1; 2&#b7;9 142 &#b1; 2&#b7;4 38&#b7;7 &#b1; 1&#b7;8 67 (52-79)ߥ 53 (38-68) èc;F508/G85E 43 9&#b7;2 &#b1; 1&#b7;8ߥ 99 &#b1; 2&#b7;3&#a7; 76 &#b1; 2&#b7;5 90 &#b1; 2&#b7;5 142 &#b1; 2&#b7;9 38&#b7;3 &#b1; 2&#b7;2 88 (75-95) 52 (35-68) èc;F508/3659DC 40 1&#b7;1 &#b1; 0&#b7;4 105 &#b1; 2&#b7;1 76 &#b1; 3&#b7;9 88 &#b1; 4&#b7;1 139 &#b1; 1&#b7;9 36&#b7;6 &#b1; 1&#b7;2 92 (77-97) 55 (39-69) èc;F508/A455E 29 14&#b7;3 &#b1; 2&#b7;0ߥ 89 &#b1; 3&#b7;1ߥ 98 &#b1; 4&#b7;0ߥ 104 &#b1; 3&#b7;4ߥ 138 &#b1; 3&#b7;4 42&#b7;1 &#b1; 2&#b7;5&#a7; 60 (41--76)ߥ 17 (8-32)ߥ èc;F508/R334W 28 13&#b7;2 &#b1; 3&#b7;0ߥ 104 &#b1; 3&#b7;2 86 &#b1; 3&#b7;4&#a7; 94 &#b1; 3&#b7;3 138 &#b1; 3&#b7;2 42&#b7;3 &#b1; 3&#b7;5 67 (46-82)ߥ 51 (32--70) èc;F508/R1162X 26 1&#b7;9 &#b1; 1&#b7;1 101 &#b1; 2&#b7;3 77 &#b1; 4&#b7;2 92 &#b1; 4&#b7;6 138 &#b1; 1&#b7;8 36&#b7;5 &#b1; 1&#b7;4 92 (75-98) 65 (47-80) èc;F508/1898+1G 20 1&#b7;2 &#b1; 0&#b7;3 99 &#b1; 2&#b7;8 83 &#b1; 4&#b7;1 94 &#b1; 4&#b7;4 138 &#b1; 3&#b7;3 35&#b7;1 &#b1; 2&#b7;1 85 (61--95) 63 (39-82) èc;F508/2184DA 20 2&#b7;3 &#b1; 0&#b7;9 106 &#b1; 5&#b7;3 82 &#b1; 4&#b7;3 92 &#b1; 4&#b7;4 141 &#b1; 3&#b7;0 36&#b7;5 &#b1; 1&#b7;5 94 (69-99) 60 (38-79) èc;F508/711+1G 17 1&#b7;3 &#b1; 0&#b7;5 108 &#b1; 4&#b7;6 83 &#b1; 4&#b7;2 94 &#b1; 4&#b7;4 137 &#b1; 3&#b7;4 36&#b7;7 &#b1; 2&#b7;9 100 73 (50-88) èc;F508/S549N 11 6&#b7;4 &#b1; 1&#b7;9&#a7; 109 &#b1; 5&#b7;7 67 &#b1; 6&#b7;1 77 &#b1; 7&#b7;2 140 &#b1; 3&#b7;2 36&#b7;7 &#b1; 2&#b7;6 92 (62-99) 71 (40--90) èc;F508/Other 2 262 5&#b7;8 &#b1; 0&#b7;2ߥ 99 &#b1; 0&#b7;4ߥ 80 &#b1; 0&#b7;5ߥ 91 &#b1; 0&#b7;5ߥ 141 &#b1; 0&#b7;3 38&#b7;1 &#b1; 0&#b7;3ߥ 86 (84-87)ߥ 50 (48-52)ߥ Other/Other 1 551 7&#b7;5 &#b1; 0&#b7;3ߥ 93 &#b1; 0&#b7;6ߥ 82 &#b1; 0&#b7;6ߥ 90 &#b1; 0&#b7;6&#a7; 141 &#b1; 0&#b7;4 38&#b7;3 &#b1; 0&#b7;3ߥ 81 (80-84)ߥ 40 (38-43)ߥ Data are mean (SE) unless otherwise indicated. Login to comment
74 Patients with genotypes èc;F508/ R117H, èc;F508/A455E, èc;F508/èc;I507 and èc;F508/ 2789+5G࢐A had significantly better lung function and lower rates of P aeruginosa colonisation than èc;F508 homozygotes. Login to comment
106 Our work confirms previous findings that èc;F508/R117H,9 èc;F508/A455E,12 èc;F508/3849+10 kbC࢐T,13,25 and èc;F508/2789+5G࢐A13,25 are associated with mild clinical manifestations. Login to comment
123 The frequency of èc;F508 homozygotes and heterozygotes is similar to that of Kerem and co-workers.6 Rates of pancreatic insufficiency in the cohorts with èc;F508/R117H and èc;F508/A455E genotypes are higher than that recorded by others.9,12,27 This finding is probably related to an overestimation of pancreatic insufficiency from use of a surrogate marker- pancreatic enzyme supplementation. Login to comment

[hide] Simultaneous screening for 11 mutations in the cys... Mol Cell Probes. 1992 Feb;6(1):33-9. Cuppens H, Buyse I, Baens M, Marynen P, Cassiman JJ
Simultaneous screening for 11 mutations in the cystic fibrosis transmembrane conductance regulator gene by multiplex amplification and reverse dot-blot.
Mol Cell Probes. 1992 Feb;6(1):33-9., [PMID:1372093]

Abstract [show]
An assay is described in which 11 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene can be screened simultaneously. Six different exons of the CFTR gene are amplified in a single multiplex amplification. Biotinylated dUTP is incorporated into the different fragments during the amplification process. A sample of this mixture is then hybridized to 21 different poly-dT tailed oligonucleotide probes which are bound to a nylon membrane. In order to screen the different mutations in a single step hybridization, the length of the different oligonucleotides and the amount used in the assay were optimized. The detection is performed by binding avidin-alkaline phosphatase to the biotin, followed by a chemiluminescent reaction. By means of this fast and sensitive assay, about 85% of all the cystic fibrosis mutations in the Belgian population can be detected.

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35 Mutation Number of CF chromosomes with the mutation Reference AF508 138(71-1%) 3 G542X 11 (5 .7%) 9 N1303K 6(3-1%) 15 1717-1G--*A 5 (2.6%) 8, 9 A455E 2 (1 .0%) 9 W1282X 2 (1 .0%) 10 G458V 1 (0.5%) 4 A1507 1 (0.5%) 9 Unidentified 28 (14.4%) cation was carried out on a DNA Thermal Cycler (Perkin Elmer-Cetus Instruments) . Login to comment
97 621 + IG-T A455E G458V A1507 AF508 1717-IG - A G542X G551D R553X WI282X N 1303 K 621+IG- .T A455E G458V A1507 AF508 1717-I G-> A G542X G551D R553X W1282X N1303K Fig. 2. Login to comment
100 Hybridization of pooled PCR products containing the mutant type alleles, obtained by amplification with mutant oligonucleotide probes, for the 621 +1G-+T, A455E, 1717-1G-+A mutations (F), the G458V, R553X, W1282X mutations (G) and the A1507, C551 D mutations (H) . Login to comment
101 A E M W Non-radioactive CF reverse dot-blot 37 B F M W C M W D M W G H 621 + IGT A455E G458V A1507 A F508 1717-IGA G542X G551D R553 X W1282X N1303K 621+IG-ߦT A455E G458V L 1507 AF508 1717-IG- A G542 X G551D R553X W1282X N 1303 K A F M W G B M W C H M W D M W E J M W Fig. 3. Login to comment

[hide] Cystic fibrosis. Am J Clin Pathol. 2003 Dec;120 Suppl:S3-13. Lewis MJ, Lewis EH 3rd, Amos JA, Tsongalis GJ
Cystic fibrosis.
Am J Clin Pathol. 2003 Dec;120 Suppl:S3-13., [PMID:15298139]

Abstract [show]
On a daily basis, pathologists examine the fundamental basis of human diseases using morphologic, immunologic, and molecular techniques. Cystic fibrosis (CF), as a clinically heterogeneous disease, exemplifies the complex challenges of genetic diseases for the pathologist who attempts to explain the mechanisms of disease and provide rationale for clinical management. This review includes an overview of CF and a discussion of pathophysiologic features and practical components of clinical and anatomic pathology, and concludes with a review of molecular diagnostics.

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95 ēa; ēa;Table 3ēa; ēa; Recommended Mutation Panel for Cystic Fibrosis Carrier Screening ࢞F508 ࢞I507 G542X G551D W1282X N1303K R553X 621+1G>T R117H 1717-1G>A A455E R560T R1162X G85E R334W R347P 711+1G>T 1898+1G>A 2184delA 1078delT 3849+10kbC>T 2789+5G>A 3659delC I148T 3120+1G>A I506V* I507V* F508C* 5T/7T/9T* * Reflex tests. Login to comment

[hide] The cystic fibrosis transmembrane conductance regu... J Cyst Fibros. 2002 Mar;1(1):13-29. Vankeerberghen A, Cuppens H, Cassiman JJ
The cystic fibrosis transmembrane conductance regulator: an intriguing protein with pleiotropic functions.
J Cyst Fibros. 2002 Mar;1(1):13-29., [PMID:15463806]

Abstract [show]
Cystic fibrosis is a frequent autosomal recessive disorder that is caused by the malfunctioning of a small chloride channel, the cystic fibrosis transmembrane conductance regulator. The protein is found in the apical membrane of epithelial cells lining exocrine glands. Absence of this channel results in imbalance of ion concentrations across the cell membrane. As a result, fluids secreted through these glands become more viscous and, in the end, ducts become plugged and atrophic. Little is known about the pathways that link the malfunctioning of the CFTR protein with the observed clinical phenotype. Moreover, there is no strict correlation between specific CFTR mutations and the CF phenotype. This might be explained by the fact that environmental and additional genetic factors may influence the phenotype. The CFTR protein itself is regulated at the maturational level by chaperones and SNARE proteins and at the functional level by several protein kinases. Moreover, CFTR functions also as a regulator of other ion channels and of intracellular membrane transport processes. In order to be able to function as a protein with pleiotropic actions, CFTR seems to be linked with other proteins and with the cytoskeleton through interaction with PDZ-domain-containing proteins at the apical pole of the cell. Progress in cystic fibrosis research is substantial, but still leaves many questions unanswered.

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241 The CFTR sequences essential for Cl transport and activation of y ORCC seem to be different: A455E and G551D are two CFTR mutations resulting in CFTR channels with reduced chloride transport but A455E retains its ability to stimulate ORCC and not G551d. Login to comment
242 A455E is associated with mild lung disease, G551D with severe, pointing to the importance of the regulatory properties of CFTR w103x. Login to comment
390 Mutations that cause a small defect in maturation but normal or increased chloride transport activity, like A455E and P574H tend to be classified in this fifth class of mutations w162x. Login to comment
394 Mutational analysis showed that two CFTR mutations resulting in CFTR channels with reduced chloride transport, A455E and G551D, have a different impact on the regulation of ORCC: A455E retains its ability to stimulate ORCC and G551D not w103x. Login to comment

[hide] Diagnosis of cystic fibrosis in adults with diffus... J Cyst Fibros. 2004 Mar;3(1):15-22. Hubert D, Fajac I, Bienvenu T, Desmazes-Dufeu N, Ellaffi M, Dall'ava-Santucci J, Dusser D
Diagnosis of cystic fibrosis in adults with diffuse bronchiectasis.
J Cyst Fibros. 2004 Mar;3(1):15-22., [PMID:15463882]

Abstract [show]
We assessed the contribution of the sweat test, genotyping and nasal potential difference (NPD) in the diagnosis of cystic fibrosis (CF) in adults with diffuse bronchiectasis (DB). Among 601 adults referred for DB from 1992 to 2001, 46 were diagnosed with CF. The sweat test was positive in 37 patients and normal or intermediate in nine patients. Two CF mutations were identified in 18 patients (39%) by screening for 31 mutations and in 36 patients (78%) after complete genetic analysis. NPD was suggestive of CF in 71% of the patients. The combination of the sweat test and genetic analysis led to the diagnosis of CF in 45 patients. In the nine patients with normal or intermediate sweat test, the diagnosis was confirmed by screening for 31 mutations in five, by complete genetic screening in three, and by NPD in the remaining patient. Searching for CF should start with sweat test. If the sweat test is normal or intermediate, screening for 31 mutations may help to diagnose CF. A complete genetic analysis is indicated when only one mutation is detected and/or when other clinical features, such as obstructive azoospermia or pancreatic insufficiency, are suggestive of CF. NPD measurement is indicated in controversial cases.

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47 We used an oligonucleotide ligation assay using a commercially available kit (Cystic Fibrosis Assay, Applied Biosystems, Foster City, CA, USA) to seek 31 mutations in the CFTR gene (F508del, I507del, Q943X, V520F, 1717y1GࡊA, G542X, G551D, R553X, R560T, S549R, S549 N, 3849q10kbCࡊT, 3849q4AࡊG, R1162X, 3659delC, W1282X, 3905insT, 621q1GࡊT, R117H, Y122X, 711q1GࡊT, 1078delT, R347P, R347H, R334 W, A455E, N1303K, G85E, 1898q1GࡊA, 2183AAࡊG, 2789q5GࡊA) which allowed to detect 82% of the CF alleles in France. Login to comment
129 * 31 mutations: F508del, I507del, Q493X, V520F, 1717y1GࡊA, G542X, G551D, R553X, R560T, S549R, S549 N, 3849q10kbCࡊT, 3849q ** 4AࡊG, R1162X, 3659delC, W1282X, 3905insT, 621q1GࡊT, R117H, Y122X, 711q1GࡊT, 1078delT, R347P, R347H, R334 W, A455E, N1303K, G85E, 1898q1GࡊA, 2183AAࡊG, 2789q5GࡊA. that the laboratory criteria for the diagnosis of CF should be expanded to include identification of CFTR mutations and abnormal bioelectrical properties of the nasal epithelium, in addition to the sweat test w7x. Login to comment
149 The next most frequent mutations were the 2183AAࡊG, 3849q10kbCࡊT, 3272y26AࡊG, A455E and 2789q5GࡊA mutations, which were all found in at least three patients. Login to comment
150 The 3849q10kbCࡊT, 3272y26A)G, A455E and 2789q 5GࡊA mutations belong to the class V of CFTR mutations, which result in residual levels of CFTR transcripts and protein w17,24x. Login to comment
151 The A455E missense mutation is associated with mild lung disease w27x, whereas the 3272y26AࡊG w28x, 2789q5GࡊA w29x and 3849q10kbCࡊT w22x mutations are associated with a milder CF phenotype. Login to comment

[hide] A 96-well formatted method for exon and exon/intro... Anal Biochem. 2006 Jun 15;353(2):226-35. Epub 2006 Apr 5. Lucarelli M, Narzi L, Piergentili R, Ferraguti G, Grandoni F, Quattrucci S, Strom R
A 96-well formatted method for exon and exon/intron boundary full sequencing of the CFTR gene.
Anal Biochem. 2006 Jun 15;353(2):226-35. Epub 2006 Apr 5., [PMID:16635477]

Abstract [show]
Full genotypic characterization of subjects affected by cystic fibrosis (CF) is essential for the definition of the genotype-phenotype correlation as well as for the enhancement of the diagnostic and prognostic value of the genetic investigation. High-sensitivity diagnostic methods, capable of full scanning of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, are needed to enhance the significance of these genetic assays. A method for extensive sequencing of the CFTR gene was optimized. This method was applied to subjects clinically positive for CF and to controls from the general population of central Italy as well as to a single subject heterozygous for a mild mutation and with an uncertain diagnosis. Some points that are crucial for the optimization of the method emerged: a 96-well format, primer project and purification, and amplicon purification. The optimized method displayed a high degree of diagnostic sensitivity; we identified a subset of 13 CFTR mutations that greatly enhanced the diagnostic sensitivity of common methods of mutational analysis. A novel G1244R disease causing mutation, leading to a CF phenotype with pancreatic sufficiency but early onset of pulmonary involvement, was detected in the subject with an uncertain diagnosis. Some discrepancies between our results and previously published CFTR sequence were found.

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26 None of these subjects showed any clinical manifestations of CF, nor were any positive for CFTR mutations when analyzed by means of the PCR/OLA/SCS method (Celera Diagnostics) [21], which searches for the most common worldwide 31 CFTR mutations (G85E, R117H, Y122X, 621+1G->T, 711+1G->T, 1078delT, R347P, R347H, R334W, A455E, DF508, DI507, Q493X, V520F, 1717-1G->A, G542X, G551D, R553X, R560T, S549R(T->G), S549N, 1898+1G->A, 2183AA->G, 2789+5G->A, R1162X, 3659delC, 3849+10kbC->T, 3849+4A->G, W1282X, 3905insT, N1303K), including the 12 most common in Italy [1,22]. Login to comment

[hide] CFTR gene analysis in Latin American CF patients: ... J Cyst Fibros. 2007 May;6(3):194-208. Epub 2006 Sep 11. Perez MM, Luna MC, Pivetta OH, Keyeux G
CFTR gene analysis in Latin American CF patients: heterogeneous origin and distribution of mutations across the continent.
J Cyst Fibros. 2007 May;6(3):194-208. Epub 2006 Sep 11., [PMID:16963320]

Abstract [show]
BACKGROUND: Cystic Fibrosis (CF) is the most prevalent Mendelian disorder in European populations. Despite the fact that many Latin American countries have a predominant population of European-descent, CF has remained an unknown entity until recently. Argentina and Brazil have detected the first patients around three decades ago, but in most countries this disease has remained poorly documented. Recently, other countries started publishing their results. METHODS: We present a compilation and statistical analysis of the data obtained in 10 countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Cuba, Ecuador, Mexico, Uruguay and Venezuela), with a total of 4354 unrelated CF chromosomes studied. RESULTS: The results show a wide distribution of 89 different mutations, with a maximum coverage of 62.8% of CF chromosomes/alleles in the patient's sample. Most of these mutations are frequent in Spain, Italy, and Portugal, consistent with the origin of the European settlers. A few African mutations are also present in those countries which were part of the slave trade. New mutations were also found, possibly originating in America. CONCLUSION: The profile of mutations in the CFTR gene, which reflects the heterogeneity of its inhabitants, shows the complexity of the molecular diagnosis of CF mutations in most of the Latin American countries.

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78 At least another 38 mutations have been searched for, but none of them were found in the CF patients from Latin America: p.E60X, p.Y122X, p.G178R, p.G330X, p.R347H, p.R352Q, p.S364P, p.A455E, p.Q493X, p.V520F, p.C524X, p.R560T, p.Y563D, p.P574H, p.K710X, p.Q890X, p. R1158X, p.S1196X, p.S1255X, p.D1270N, p.W1310X, p. W1316X, c.405+1G-A, c.444delA, c.556delA, c.574delA, c.1677delTA, c.2043delG, c.2307insA, c.2909delT, c.3120G-A, c.3358delAC, c.3662delA, c.3750delAG, c.3791delC, c.3821delT, c.3849+4A-G, c.3905insT. Login to comment

[hide] [Mild cystic fibrosis: genetics - extending follow... Arch Pediatr. 2009 Apr;16(4):387-90. doi: 10.1016/j.arcped.2008.12.008. Epub 2009 Jan 31. Gaillard D, Clavel C, Bessaci-Kabouya K, Abely M
[Mild cystic fibrosis: genetics - extending follow-up is necessary].
Arch Pediatr. 2009 Apr;16(4):387-90. doi: 10.1016/j.arcped.2008.12.008. Epub 2009 Jan 31., [PMID:19181498]

Abstract [show]
The diagnosis of mild cystic fibrosis is first suspected on mild lung disease or absence of pancreatic insufficiency and is assessed by biological analysis. The sweat test is not always conclusive. The nasal potential difference and molecular analysis of CFTR gene allow confirming diagnosis. A regular follow-up in cystic fibrosis clinical centre is essential all life long. The genotype, especially during neonatal period, cannot be used to predict individually the course of the disease. Genetic counselling must be recommended to the parents in order to propose an analysis of CFTR gene to give the appropriate genetic counselling and to consider with them which family members could be concerned, especially in the event of parental project. The research of heterozygote status in related for prenatal diagnosis is not recommended for all mutations.

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43 Parmi les variations de s&#e9;quence identifi&#e9;es en p&#e9;riode n&#e9;onatale par le kit &#c9;lucig&#e8;ne1 CF30, plusieurs sont reconnues comme ayant un effet mod&#e9;r&#e9;, comme R117H, R334W, R2789 + 5G > A, 3272-26A > G, 3849 + 10kbC > T [7,9,10], voire variable, notamment G85E, A455E [3] ; les 23 autres mutations sont reconnues comme s&#e9;v&#e8;res. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... Drugs. 2010 Feb 12;70(3):241-59. doi: 10.2165/11316160-000000000-00000. Becq F
Cystic fibrosis transmembrane conductance regulator modulators for personalized drug treatment of cystic fibrosis: progress to date.
Drugs. 2010 Feb 12;70(3):241-59. doi: 10.2165/11316160-000000000-00000., [PMID:20166764]

Abstract [show]
This article considers the issue of personalized drug discovery for the orphan disease cystic fibrosis (CF) to deliver a candidate for therapeutic development. CF is a very complicated disease due to numerous anomalies of the gene leading to progressive severity and morbidity. Despite extensive research efforts, 20 years after the cloning of the CF gene, CF patients are still waiting for a curative treatment as prescribed medications still target the secondary manifestations of the disease rather than the gene or the CF transmembrane conductance regulator (CFTR) protein. New therapeutics aimed at improving mutant CFTR functions, also known as 'protein repair therapy' are nevertheless hoped and predicted to replace some of the currently used therapy, while improving the quality of life as well as life expectancy of CF patients. Although there is substantial variability in the cost of treating CF between countries, a protein repair therapy should also alleviate the financial burden of medical costs for CF patients and their families. Finding new drugs or rediscovering old ones for CF is critically dependent on the delivery of molecular and structural information on the CFTR protein, on its mutated version and on the network of CFTR-interacting proteins. The expertise needed to turn compounds into marketable drugs for CF will depend on our ability to provide biological information obtained from pertinent models of the disease and on our success in transferring safe molecules to clinical trials. Predicting a drug-induced response is also an attractive challenge that could be rapidly applied to patients.

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105 [38] Class V mutations (e.g. A455E, P574H) are responsible for the production of functional proteins with normal Cl-channel activity and regulation, but at a reduced rate of synthesis. Login to comment

[hide] [Cystic fibrosis in a woman aged seventy]. Ned Tijdschr Geneeskd. 2010;154:A1342. Ras JE, van Velzen E, van Berkhout FT, van den Brand JJ
[Cystic fibrosis in a woman aged seventy].
Ned Tijdschr Geneeskd. 2010;154:A1342., [PMID:20619026]

Abstract [show]
A seventy-year-old woman was admitted to hospital with a Staphylococcus aureus respiratory tract infection. She had a history of extensive bronchiectasis and allergic bronchopulmonary aspergillosis (ABPA). Cystic fibrosis (CF) was suspected and cystic fibrosis transmembrane conductance regulator (CFTR) gene analysis showed F508del and R117H-7T mutations. In these mutations there is residual activity in the chloride channel in the cell membrane coded by the CFTR gene. This results in a much milder disease pattern varying from no disease at all to isolated organ disease. This type of disease is known as non-classical cystic fibrosis. In our patient the diagnosis of cystic fibrosis was made exceptionally late in life.

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63 TABEL 1 Classificatie van mutaties in het 'cystic fibrosis transmembrane conductance regulator`(CFTR)-gen op chromosoom 7 klasse mechanisme enkele bekende mutaties I geen synthese van het CFTR-eiwit G542X R553X W1282X R1162X 621-1G࢐T 1717-1G࢐A 1078࢞T 3659࢞C II defect in eiwitrijping met voortijdig afbraak ࢞F508 ࢞I507 N1303K S549N III verstoorde regulatie van de CFTR-functie G551D R56OT IV verstoorde conductie van chloride of verstoorde kanaalopening R117H R334W G85E R347P V minder synthese van het CFTR-eiwit 3849+10KbC࢐T 2789+5G࢐A A455E TABEL 2 Diagnostiek van cystische fibrose test testuitslag klassieke CF* niet-klassieke CFߤ zweettest chlorideconcentratie > 60 mmol/l chlorideconcentratie ࣘ 60 mmol/l neuspotentiaalmeting afwijkend niet-afwijkend CFTR-mutatie-analyse 2 mutaties 2 mutaties CF = cystische fibrose; CFTR = 'cystic fibrosis transporter regulator`-gen. Login to comment

[hide] Newborn screening for cystic fibrosis in Alberta: ... Paediatr Child Health. 2010 Nov;15(9):590-4. Lilley M, Christian S, Hume S, Scott P, Montgomery M, Semple L, Zuberbuhler P, Tabak J, Bamforth F, Somerville MJ
Newborn screening for cystic fibrosis in Alberta: Two years of experience.
Paediatr Child Health. 2010 Nov;15(9):590-4., [PMID:22043142]

Abstract [show]
On April 1, 2007, Alberta became the first province in Canada to introduce cystic fibrosis (CF) to its newborn screening program. The Alberta protocol involves a two-tier algorithm involving an immunoreactive trypsinogen measurement followed by molecular analysis using a CF panel for 39 mutations. Positive screens are followed up with sweat chloride testing and an assessment by a CF specialist. Of the 99,408 newborns screened in Alberta during the first two years of the program, 221 had a positive CF newborn screen. The program subsequently identified and initiated treatment in 31 newborns with CF. A relatively high frequency of the R117H mutation and the M1101K mutation was noted. The M1101K mutation is common in the Hutterite population. The presence of the R117H mutation has created both counselling and management dilemmas. The ability to offer CF transmembrane regulator full sequencing may help resolve diagnostic dilemmas. Counselling and management challenges are created when mutations are mild or of unknown clinical significance.

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46 These include the following mutations: delF508, I507del, G542X, G85E, R117H, 621+1G࢐T, 711+1G࢐T, G551D, R334W, R347P, A455E, 1717-1G࢐A, R560T, R553X, N1303K, 1898+1G࢐A, 2184delA, 2789+5G࢐A, 3120+1G࢐A, R1162X, 3659delC, 3849+10kbC࢐T, W1282X, 1078delT, 394delTT, Y122X, R347H, V520F, A559T, S549N, S549R, 1898+5G࢐T, 2183AA࢐G, 2307insA, Y1092X, M1101K, S1255X, 3876delA and 3905insT. Login to comment

[hide] Assessing the Disease-Liability of Mutations in CF... Cold Spring Harb Perspect Med. 2012 Dec 1;2(12):a009480. doi: 10.1101/cshperspect.a009480. Ferec C, Cutting GR
Assessing the Disease-Liability of Mutations in CFTR.
Cold Spring Harb Perspect Med. 2012 Dec 1;2(12):a009480. doi: 10.1101/cshperspect.a009480., [PMID:23209179]

Abstract [show]
Over 1900 mutations have been reported in the cystic fibrosis transmembrane conductance regulator (CFTR), the gene defective in patients with cystic fibrosis. These mutations have been discovered primarily in individuals who have features consistent with the diagnosis of CF. In some cases, it has been recognized that the mutations are not causative of cystic fibrosis but are responsible for disorders with features similar to CF, and these conditions have been termed CFTR-related disorders or CFTR-RD. There are also mutations in CFTR that do not contribute to any known disease state. Distinguishing CFTR mutations according to their penetrance for an abnormal phenotype is important for clinical management, structure/function analysis of CFTR, and understanding the molecular and cellular mechanisms underlying CF.

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101 However, when a sufficiently large number of patients with identical genotypes are found in a single geographic location such as Belgium and in French Canada, a correlation with decline in lung function becomes evident for the A455E (p.Ala455Glu) mutation (Gan et al. 1995; De Braekeleer et al. 1997). Login to comment

[hide] CFTR-mutation specific applications of CFTR-direct... J Cyst Fibros. 2013 Sep;12(5):487-96. doi: 10.1016/j.jcf.2012.12.005. Epub 2013 Jan 11. van Meegen MA, Terheggen SW, Koymans KJ, Vijftigschild LA, Dekkers JF, van der Ent CK, Beekman JM
CFTR-mutation specific applications of CFTR-directed monoclonal antibodies.
J Cyst Fibros. 2013 Sep;12(5):487-96. doi: 10.1016/j.jcf.2012.12.005. Epub 2013 Jan 11., [PMID:23317763]

Abstract [show]
BACKGROUND: Over the last decade novel monoclonal CFTR-specific antibodies have been developed. We here present a paired analysis to detect wild-type and mutant CFTR using Western blot analysis, flow cytometry and confocal microscopy in several cellular expression systems. METHODS: The following CFTR-specific antibodies were used; 217, 432, 450, 570, 769, 596, 660, L12B4 and 24.1. Mutant CFTR was detected in HEK293 cells transiently expressing the mutations; G542X, R1162X, F508del, N1303K, G551D, R117H, A455E. RESULTS: The majority of these antibodies are suitable for most applications tested. Using immunofluorescence, some antibodies can better detect mutant forms of CFTR (F508del and N1303K by mAbs 596 and 769), or display lower aspecific detection by Western blot analysis (mAbs 432, 450, 769 and 596) or immunofluorescence (mAbs 432, 450, 570 and 769). CONCLUSION: Optimal detection of CFTR by monoclonal antibodies depends on CFTR mutation and the specific research application.

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3 Mutant CFTR was detected in HEK293 cells transiently expressing the mutations; G542X, R1162X, F508del, N1303K, G551D, R117H, A455E. Login to comment
22 http://dx.doi.org/10.1016/j.jcf.2012.12.005 functional CFTR is observed for class V (A455E) and VI mutations, due to impaired biosynthesis and decreased stability of the CFTR protein, respectively [5,12]. Login to comment
23 However, many CFTR mutations cannot be strictly classified into single classes as was shown for A455E and F508del [12-14]. Login to comment
76 We selected wt-CFTR, F508del (class II), G542X (I), R1162X (I), G551D (III), R117H (IV), A455E (V), and N1303K (II) that were ectopically expressed in HEK293 cells. Login to comment
83 For class V mutant A455E, the majority of the protein was core-glycolysated band B and only limited complex-glycosylated CFTR (C-band) was observed. Login to comment
95 CFTR Mutants F508del R1162X G551D R117H A455E N1303K 596, 769, 24.1 , 570, 432,450 570, 432, 450 570, 432, 450, 24.1, 769, 596 570, 570, 596, 769, 24.1, 432, 450 596, 769, 24.1, 432, 450 769, 596, 570, 24.1, 432, 450 is likely still preserved and bound to interacting proteins that may affect the binding to specific mAbs. Login to comment
111 G551D was expressed at levels comparable to wt-CFTR, expression of R117H, N1303K, A455E and R1162X was intermediate, and low levels were observed for F508del and G542X. Login to comment
145 Western blots containing 25 bc;g of total protein of HEK293 cells transiently transfected with pcDNA3 containing; CFTR-wt, F508del, G542X, R1162X, G551D, R117H, A455E, N1303K or empty vector. Login to comment
152 Limited detection was observed for R1162X and A455E. Login to comment
155 Detection of CFTR was limited for F508del and A455E and CFTR mutants G542X and R1162X were not detectable. Login to comment
217 Interestingly, for mutant A455E we demonstrated CFTR protein levels slightly higher than mutant F508del, with comparable B-C ratio (quantification not shown), suggesting that trafficking is impaired as well. Login to comment
218 A455E is considered to be a mild mutation as it is associated with pancreas sufficiency (http://cftr2.org), indicating that the limited levels of A455E C-band have increased activity as compared to N1303K and F508del, as previously noted [33], or that some A455E B-band may have activity at the plasma membrane as has been described for F508del [34]. Login to comment
220 Furthermore, we provide more insight on the impact of CFTR mutations N1303K, A455E, G551D and R117H on CFTR expression. Login to comment

[hide] CFTR p.Arg117His associated with CBAVD and other C... J Med Genet. 2013 Apr;50(4):220-7. doi: 10.1136/jmedgenet-2012-101427. Epub 2013 Feb 1. Thauvin-Robinet C, Munck A, Huet F, de Becdelievre A, Jimenez C, Lalau G, Gautier E, Rollet J, Flori J, Nove-Josserand R, Soufir JC, Haloun A, Hubert D, Houssin E, Bellis G, Rault G, David A, Janny L, Chiron R, Rives N, Hairion D, Collignon P, Valeri A, Karsenty G, Rossi A, Audrezet MP, Ferec C, Leclerc J, Georges Md, Claustres M, Bienvenu T, Gerard B, Boisseau P, Cabet-Bey F, Cheillan D, Feldmann D, Clavel C, Bieth E, Iron A, Simon-Bouy B, Izard V, Steffann J, Viville S, Costa C, Drouineaud V, Fauque P, Bi
CFTR p.Arg117His associated with CBAVD and other CFTR-related disorders.
J Med Genet. 2013 Apr;50(4):220-7. doi: 10.1136/jmedgenet-2012-101427. Epub 2013 Feb 1., [PMID:23378603]

Abstract [show]
BACKGROUND: The high frequency of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene mutation p.Arg117His in patients with congenital bilateral absence of the vas deferens (CBAVD) and in newborns screened for CF has created a dilemma. METHODS: Phenotypic and genotypic data were retrospectively collected in 179 non-newborn French individuals carrying p.Arg117His and a second CFTR mutation referred for symptoms or family history, by all French molecular genetics laboratories, referring physicians, CF care centres and infertility clinics. RESULTS: 97% of the patients had the intronic T7 normal variant in cis with p.Arg117His. 89% patients were male, with CBAVD being the reason for referral in 76%. In 166/179 patients with available detailed clinical features, final diagnoses were: four late-onset marked pulmonary disease, 83 isolated CBAVD, 67 other CFTR-related phenotypes, including 44 CBAVD with pulmonary and/or pancreatic symptoms and 12 asymptomatic cases. Respiratory symptoms were observed in 30% of the patients, but the overall phenotype was mild. No correlation was observed between sweat chloride concentrations and disease severity. Five couples at risk of CF offspring were identified and four benefited from prenatal or preimplantation genetic diagnoses (PND or PGD). Eight children were born, including four who were compound heterozygous for p.Arg117His and one with a severe CF mutation. CONCLUSIONS: Patients with CBAVD carrying p.Arg117His and a severe CF mutation should benefit from a clinical evaluation and follow-up. Depending on the CBAVD patients' genotype, a CFTR analysis should be considered in their partners in order to identify CF carrier couples and offer PND or PGD.

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125 (Ala455Glu);( Arg117His) p.Gly551Asp 1995 No spontaneous pregnancy and no in vitro fertilisation - CF or CFTR-RD p. Login to comment

[hide] Targeting a genetic defect: cystic fibrosis transm... Eur Respir Rev. 2013 Mar 1;22(127):58-65. doi: 10.1183/09059180.00008412. Derichs N
Targeting a genetic defect: cystic fibrosis transmembrane conductance regulator modulators in cystic fibrosis.
Eur Respir Rev. 2013 Mar 1;22(127):58-65. doi: 10.1183/09059180.00008412., [PMID:23457166]

Abstract [show]
Cystic fibrosis (CF) is caused by genetic mutations that affect the cystic fibrosis transmembrane conductance regulator (CFTR) protein. These mutations can impact the synthesis and transfer of the CFTR protein to the apical membrane of epithelial cells, as well as influencing the gating or conductance of chloride and bicarbonate ions through the channel. CFTR dysfunction results in ionic imbalance of epithelial secretions in several organ systems, such as the pancreas, gastrointestinal tract, liver and the respiratory system. Since discovery of the CFTR gene in 1989, research has focussed on targeting the underlying genetic defect to identify a disease-modifying treatment for CF. Investigated management strategies have included gene therapy and the development of small molecules that target CFTR mutations, known as CFTR modulators. CFTR modulators are typically identified by high-throughput screening assays, followed by preclinical validation using cell culture systems. Recently, one such modulator, the CFTR potentiator ivacaftor, was approved as an oral therapy for CF patients with the G551D-CFTR mutation. The clinical development of ivacaftor not only represents a breakthrough in CF care but also serves as a noteworthy example of personalised medicine.

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76 ASL hydration is achieved through establishment of an osmotic gradient by a predominant efflux of chloride ions through CFTR channels, coupled with a moderate influx of sodium ions through epithelial 100 80 60 40 20 0 Sweat chloride mmol&#b7;L -1 Sweat chloride in CF CFTR protein function % 20 0 40 60 80 100 >60 mmol&#b7;L-1 diagnostic cut-off for CF Normal Normal Carriers Carriers CF with pancreatic insufficiency Class I-III (F508del, G551D, W1282X) CF with pancreatic sufficiency Class IV-V (3849+10kbC-T, A455E) CBAVD with two CF mutations (R117H, 5T) CFTR-related disorder (pancreatitis, bronchiectasis, CBAVD) Adults ? Login to comment

[hide] Apical CFTR expression in human nasal epithelium c... PLoS One. 2013;8(3):e57617. doi: 10.1371/journal.pone.0057617. Epub 2013 Mar 6. van Meegen MA, Terheggen-Lagro SW, Koymans KJ, van der Ent CK, Beekman JM
Apical CFTR expression in human nasal epithelium correlates with lung disease in cystic fibrosis.
PLoS One. 2013;8(3):e57617. doi: 10.1371/journal.pone.0057617. Epub 2013 Mar 6., [PMID:23483918]

Abstract [show]
INTRODUCTION: Although most individuals with cystic fibrosis (CF) develop progressive obstructive lung disease, disease severity is highly variable, even for individuals with similar CFTR mutations. Measurements of chloride transport as expression of CFTR function in nasal epithelial cells correlate with pulmonary function and suggest that F508del-CFTR is expressed at the apical membrane. However, an association between quantitative apical CFTR expression in nasal epithelium and CF disease severity is still missing. METHODS AND MATERIALS: Nasal epithelial cells from healthy individuals and individuals with CF between 12-18 years were obtained by nasal brushing. Apical CFTR expression was measured by confocal microscopy using CFTR mAb 596. Expression was compared between both groups and expression in CF nasal epithelial cells was associated with standardized pulmonary function (FEV1%). RESULTS: The proportion of cells expressing apical CFTR in columnar epithelium is lower in CF compared to non-CF. The apical CFTR expression level was significantly correlated with FEV1% in F508del homozygous subjects (r = 0.63, p = 0.012). CONCLUSION: CFTR expression in nasal epithelial cells is lower in subjects with CF compared to healthy subjects. The proportion of cells expressing F508del-CFTR at the apical membrane is variable between subjects and is positively correlated with FEV1% in F508del-CFTR homozygous subjects.

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66 62% yes insufficient 3 F508del/A455E F 18. Login to comment
208 1717-1G.A Class I altered splicing 365insT Class I frameshift 4243-3T.A Class V altered splicing A455E Class II, V missense F508del Class II, III, VI amino acid deletion IVS11-1G.C Class I altered splicing R553X Class I nonsense S1252N Class III missense doi:10.1371/journal.pone.0057617.t003 Supporting Information Figure S1 Bland-Altman plots. Login to comment

[hide] Clinical and genetic features in patients with cys... Iran J Pediatr. 2013 Apr;23(2):212-5. Farjadian S, Moghtaderi M, Kashef S, Alyasin S, Najib K, Saki F
Clinical and genetic features in patients with cystic fibrosis in southwestern iran.
Iran J Pediatr. 2013 Apr;23(2):212-5., [PMID:23724185]

Abstract [show]
OBJECTIVE: Cystic fibrosis (CF) is a common autosomal recessive genetic disease caused by a mutation in the CF transmembrane conductance regulatory (CFTR) gene. This study attempted to identify the most common CFTR mutations and any correlations between certain mutations and the clinical presentation of the disease in CF patients in southwestern Iran. METHODS: Twenty nine common CFTR gene mutations were examined in 45 CF patients. FINDINGS: Chronic cough, intestinal obstruction, dehydration, heat exhaustion and steatorrhea were the most common early clinical symptoms among our patients. The most common mutation was DeltaF508, with an allele frequency of 21%. The homozygous DeltaF508 mutation was observed in eight patients (18%), and three patients (7%) were DeltaF508 carriers. The 2183AA > G mutation was observed in four patients, one of whom was also a DeltaF508 carrier. The R1162X mutation was detected in two patients. The G542X, R334W and N1303K mutations were detected each in one patient, the first of whom was also a DeltaF508 carrier. CONCLUSION: Out of 45 patients, 27 (60%) had none of the CFTR gene mutations we tested for. The most frequent mutations in southwestern Iranian patients with CF should be identified by sequencing the entire CFTR gene in order to optimize the design of a diagnostic kit for common regional mutations.

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26 Genomic DNA was extracted from 200 &#b5;L of whole blood with the QiaAmp DNA Mini Kit (Qiagen, Valencia, CA, USA) and 29 common CFTR gene mutations (D1152H, 1717-1G>A, G542X, W1282X, N1303K, ࢞F508, 3849+10kbC>T, 394delTT, 621+1G>T, S1251N, G551D, R117H, R1162X, R334W, A455E, 2183AA>G, 3659delC, 1078delT, ࢞I507, R347P, R553X, E60X, 3120+1G>A, 2789+5G>A, 1898+1G>A, 711+1G>T, G85E, 2184delA and R560T) were analyzed with the ELUCIGENE CF29 v. 2 kit using four multiplex PCR. Login to comment

[hide] A functional CFTR assay using primary cystic fibro... Nat Med. 2013 Jul;19(7):939-45. doi: 10.1038/nm.3201. Epub 2013 Jun 2. Dekkers JF, Wiegerinck CL, de Jonge HR, Bronsveld I, Janssens HM, de Winter-de Groot KM, Brandsma AM, de Jong NW, Bijvelds MJ, Scholte BJ, Nieuwenhuis EE, van den Brink S, Clevers H, van der Ent CK, Middendorp S, Beekman JM
A functional CFTR assay using primary cystic fibrosis intestinal organoids.
Nat Med. 2013 Jul;19(7):939-45. doi: 10.1038/nm.3201. Epub 2013 Jun 2., [PMID:23727931]

Abstract [show]
We recently established conditions allowing for long-term expansion of epithelial organoids from intestine, recapitulating essential features of the in vivo tissue architecture. Here we apply this technology to study primary intestinal organoids of people suffering from cystic fibrosis, a disease caused by mutations in CFTR, encoding cystic fibrosis transmembrane conductance regulator. Forskolin induces rapid swelling of organoids derived from healthy controls or wild-type mice, but this effect is strongly reduced in organoids of subjects with cystic fibrosis or in mice carrying the Cftr F508del mutation and is absent in Cftr-deficient organoids. This pattern is phenocopied by CFTR-specific inhibitors. Forskolin-induced swelling of in vitro-expanded human control and cystic fibrosis organoids corresponds quantitatively with forskolin-induced anion currents in freshly excised ex vivo rectal biopsies. Function of the CFTR F508del mutant protein is restored by incubation at low temperature, as well as by CFTR-restoring compounds. This relatively simple and robust assay will facilitate diagnosis, functional studies, drug development and personalized medicine approaches in cystic fibrosis.

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127 (d) Forskolin-induced swelling of rectal organoids derived from three individual healthy controls, two individuals with a mild cystic fibrosis genotype (F508del A455E) and nine individuals with a severe cystic fibrosis genotype (one individual with E60X 4015ATTTdel, one with F508del G542X, one with F508del L927P and six with F508del F508del). Login to comment
140 We next compared the efficacy of approaches to restore the function of F508del CFTR by comparing the amount of FIS to that in mock-treated F508del A455E organoids or healthy control organoids (Fig. 5d). Login to comment
141 This comparison indicated that VX-809 is the most potent corrector and combined treatment with VX-809 and VX-770 induced FIS beyond the amounts in F508del A455E organoids, reaching ~60% of the FIS in healthy controls. Login to comment
150 0 500 1,000 1,500 2,000 2,500 0 500 1,000 1,500 2,000 2,500 3,000 0 400 800 1,200 1,600 C8 Corr-4a C8 + Corr-4a VX-809 VX-770 VX-809 + VX-770 VRT-325 Corr-4a VRT-325 + Corr-4a CF1 CF6 CF5 CF4 CF3 CF2 F508del L927P F508del G542X E60X 4015delATTT F508del F508del b d a c 0 20 40 60 80 100 120 V R T - 3 2 5 C o r r - 4 a C 8 V X - 8 0 9 V X - 7 7 0 V R T - 3 2 5 + C o r r - 4 a C 8 + C o r r - 4 a V X - 8 0 9 + V X - 7 7 0 C o n t r o l C o n t r o l F508del F508del HC F508del A455E Organoid swelling (absolute AUC t = 60) Organoid swelling (absolute AUC t = 60) Organoid swelling (absolute AUC t = 60) Organoid swelling (normalized AUC t = 60) Figure 5ߒ Differential FIS between organoids from subjects with cystic fibrosis after chemical CFTR restoration. Login to comment
154 (d) Average FIS responses of compound-treated F508del F508del organoids (n = 6 from a-c) and DMSO-treated F508del A455E organoids (n = 2) relative to the average FIS of DMSO-treated healthy control organoids (n = 3) expressed as the AUC calculated from the time periods shown in Figure 4d-f (baseline = 100%, t = 60 min; mean &#b1; s.e.m.). Login to comment
182 This combination induces approximately 1.5-fold more FIS in CFTR F508del homozygous organoids as compared to untreated F508del A455E organoids and up to 60% of the FIS seen in healthy controls. Login to comment

[hide] A comprehensive assay for CFTR mutational analysis... Clin Chem. 2013 Oct;59(10):1481-8. doi: 10.1373/clinchem.2013.206466. Epub 2013 Jun 17. Abou Tayoun AN, Tunkey CD, Pugh TJ, Ross T, Shah M, Lee CC, Harkins TT, Wells WA, Tafe LJ, Amos CI, Tsongalis GJ
A comprehensive assay for CFTR mutational analysis using next-generation sequencing.
Clin Chem. 2013 Oct;59(10):1481-8. doi: 10.1373/clinchem.2013.206466. Epub 2013 Jun 17., [PMID:23775370]

Abstract [show]
BACKGROUND: Cystic fibrosis is a life-threatening genetic disorder that has been associated with mutations in the CFTR [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)] gene. Hundreds of CFTR mutations have been detected to date. Current CFTR genotyping assays target a subset of these mutations, particularly a mutation panel recommended by the American College of Medical Genetics for carrier screening of the general population. Fast sequencing of the entire coding sequence in a scalable manner could expand the detection of CFTR mutations and facilitate management of costs and turnaround times in the clinical laboratory. METHODS: We describe a proof-of-concept CFTR assay that uses PCR target enrichment and next-generation sequencing on the Ion Torrent Personal Genome Machine (PGM) platform. RESULTS: The scalability of the assay was demonstrated, with an average mean depth of coverage ranging from 500x to 3500x, depending on the number of multiplexed patient samples and the Ion Torrent chip used. In a blinded study of 79 previously genotyped patient DNA samples and cell lines, our assay detected most of the mutations, including single-nucleotide variants, small insertions and deletions, and large copy-number variants. The reproducibility was 100% for detecting mutations in independent runs. Our assay demonstrated high specificity, with only 2 false-positive calls (at 2184delA) found in 2 samples caused by a sequencing error in a homopolymer stretch of sequence. The detection rate for variants of unknown significance was very low in the targeted region. CONCLUSIONS: With continued optimization and system refinements, PGM sequencing promises to be a powerful, rapid, and scalable means of clinical diagnostic sequencing.

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53 of cases af9;/af9; c.1521_1523delCTT; c.1521_1523delCTT èc;F508; èc;F508 CF Yes 97 Dartmouth 1 af9;/af9; c.1521_1523delCTT; c.350Gb0e;A èc;F508; R117H CF Yes 53; 50 Dartmouth 1 af9;/af9; c.350Gb0e;A; c.1477Cb0e;T R117H; Q493*b CF Yes 52; 49 Dartmouth 1 af9;/af9; c.1521_1523delCTT; c.1000Cb0e;T èc;F508; R334W CF Yes 49; 54 Dartmouth 1 af9;/af9; c.1521_1523delCTT; c.489af9;1Gb0e;T èc;F508; 621af9;1Gb0e;T CF Yes 48; 47 Dartmouth 1 af9;/af9; c.1521_1523delCTT; c.1364Cb0e;A èc;F508; A455E CF Yes 51; 46 Dartmouth 1 af9;/af9; c.489af9;1Gb0e;T; c.2988af9;1Gb0e;A 621af9;1Gb0e;T; 3120af9;1Gb0e;A CF Yes 48; 49 Coriell 1 af9;/af9; c.1521_1523delCTT; c.1657Cb0e;T èc;F508; R553* CF Yes 44; 49c Coriell 2 af9;/af9; c.1521_1523delCTT; c.3528delC èc;F508; 3659delC CF Yes 46; 46 Coriell 1 af9;/af9; c.489af9;1Gb0e;T; c.579af9;1Gb0e;T 621af9;1Gb0e;T; 711af9;1Gb0e;T CF Yes 50; 51 Coriell 1 af9;/af9; c.489af9;1Gb0e;T; c.254Gb0e;A 621af9;1Gb0e;T; G85E CF Yes 50; 45 Coriell 1 af9;/af9; c.1521_1523delCTT; c.1679Gb0e;C èc;F508; R560T CF Yes 44; 52 Coriell 1 af9;/af9; c.489af9;1Gb0e;T; c.1364Cb0e;A 621af9;1Gb0e;T; A455E CF Yes 50; 49 Coriell 1 af9;/af9; c.3909Cb0e;G; c.4046Gb0e;A N1303K; G1349D CF Yes 47; 52 Coriell 1 af9;/af9; c.2657af9;5Gb0e;A; c.2657af9;5Gb0e;A 2789af9;5Gb0e;A; 2789af9;5Gb0e;A CF Yes 100 Coriell 1 af9;/af9; c.1040Gb0e;C; c.1652Gb0e;A R347P; G551D CF Yes 51; 49 Coriell 1 af9;/af9; c.1000Cb0e;T; c.3368-2Ab0e;T R334W; 3500-2Ab0e;G CF Yes 53; 45 Coriell 1 af9;/af9; c.254Gb0e;A; c.3454Gb0e;C G85E; D1152H CF Yes 44; 47 Coriell 1 af9;/af9; c.1521_1523delCTT; c.350Gb0e;A èc;F508; R117H CF Yes 49; 50 Coriell 1 af9;/af9; c.1521_1523delCTT; c.54-5940_273af9;10250del21kb èc;F508; CFTRdel2,3 CF Yes 47; N/Ad Coriell 1 af9;/af9; c.1521_1523delCTT; c.1766af9;1Gb0e;A èc;F508; 1898af9;1Gb0e;A CF Yes 47; 50 Coriell 1 af9;/af9; c.1521_1523delCTT; c.2051_2052delAAinsG èc;F508; K684Sfs CF Yes 47; 50 Coriell 1 af9;/af9; c.1521_1523delCTT; c.2052del èc;F508; K684Nfs*38 CF Yes 51; 55 Coriell 1 af9;/afa; c.1521_1523delCTT èc;F508 Carrier Yes 50c Dartmouth 16 af9;/afa; c.1652Gb0e;A G551D Carrier Yes 50c Dartmouth 5 af9;/afa; c.1519_1521delATC èc;I507 Carrier Yes 46 Dartmouth 1 af9;/afa; c.3454Gb0e;C D1152H Carrier Yes 50 Dartmouth 1 af9;/afa; c.1657Cb0e;T R553* Carrier Yes 51 Dartmouth 1 af9;/afa; c.178Gb0e;T E60* Carrier Yes 51 Dartmouth 1 af9;/afa; c.3846Gb0e;A W1282* Carrier Yes 45c Dartmouth 3 af9;/afa; c.1000Cb0e;T R334W Carrier Yes 51 Dartmouth 1 af9;/afa; c.1624Gb0e;T G542* Carrier Yes 47c Dartmouth 4 af9;/afa; c.3484Cb0e;T R1162* Carrier Yes 43 Dartmouth 1 af9;/afa; c.1766af9;1Gb0e;A 1898af9;1Gb0e;A Carrier Yes 57 Dartmouth 1 af9;/afa; c.3773_3774insT 3905insT (L1258Ffs*7) Carrier Yes 37 Dartmouth 1 af9;/afa; c.350Gb0e;A R117H Carrier Yes 50c Dartmouth 3 af9;/afa; c.1645Ab0e;C S549R Ab0e;C Carrier No N/A Dartmouth 1 af9;/afa; c.1040Gb0e;A R347H Carrier Yes 47 Dartmouth 1 af9;/afa; c.3909Cb0e;G N1303K Carrier Yes 46 Dartmouth 1 af9;/afa; c.3718-2477Cb0e;T 3849af9;10kbCb0e;T Carrier Yes 51 Coriell 1 af9;/afa; c.2988af9;1Gb0e;A 3120af9;1Gb0e;A Carrier Yes 49 Coriell 1 af9;/afa; c.489af9;1Gb0e;T 621af9;1Gb0e;T Carrier Yes 50 Coriell 1 af9;/afa; c.1585-1Gb0e;A 1717-1Gb0e;A Carrier Yes 51 Coriell 1 afa;/afa;e N/Af N/A Normal N/A N/A Dartmouth 9 a af9;/af9;, 2 pathogenic mutations; af9;/afa;, carrier of a single pathogenic mutation; afa;/afa;, absence of any pathogenic mutations. Login to comment
115 Mutation cDNA position Mutation class Sensitivity (TPa ) Specificity (TN) Accuracyb G85E c.254Gb0e;A Missense Detected (2/2) 100% (77/77) 100% R117H c.350Gb0e;A Missense Detected (6/6) 100% (73/73) 100% 621af9;1Gb0e;T c.489af9;1Gb0e;T Splice site Detected (6/6) 100% (73/73) 100% 711af9;1Gb0e;T c.579af9;1Gb0e;T Splice site Detected (1/1) 100% (78/78) 100% R334W c.1000Cb0e;T Missense Detected (3/3) 100% (76/76) 100% R347P c.1040Gb0e;C Missense Detected (1/1) 100% (78/78) 100% A455E c.1364Cb0e;A Missense Detected (2/2) 100% (77/77) 100% èc;I507 c.1519_1521delATC In-frame deletion Detected (1/1) 100% (78/78) 100% èc;F508 c.1521_1523delCTT In-frame deletion Detected (30/30) 100% (49/49) 100% G542* c.1624Gb0e;T Nonsense Detected (4/4) 100% (75/75) 100% G551D c.1652Gb0e;A Missense Detected (6/6) 100% (73/73) 100% R553* c.1657Cb0e;T Nonsense Detected (3/3) 100% (76/76) 100% R560T c.1679Gb0e;C Missense Detected (1/1) 100% (78/78) 100% 1898af9;1Gb0e;A c.1766af9;1Gb0e;A Splice site Detected (2/2) 100% (77/77) 100% 2789af9;5Gb0e;A c.2657af9;5Gb0e;A Splice site Detected (1/1) 100% (78/78) 100% 3120af9;1Gb0e;A c.2988af9;1Gb0e;A Splice site Detected (2/2) 100% (77/77) 100% R1162* c.3484Cb0e;T Nonsense Detected (1/1) 100% (78/78) 100% 3659delC c.3528del Frameshift deletion Detected (1/1) 100% (78/78) 100% 3849af9;10kbCb0e;T c.3718-2477Cb0e;T Splice site Detected (1/1) 100% (78/78) 100% W1282* c.3846Gb0e;A Nonsense Detected (3/3) 100% (75/75) 100% N1303K c.3909Cb0e;G Missense Detected (1/1) 100% (78/78) 100% 2184delA c.2052del Frameshift deletion Detected (1/1) 97% (76/78) 97% 1717-1Gb0e;A c.1585-1Gb0e;A Splice site Detected (1/1) 100% (78/78) 100% a TP, true-positive rate; TN, true-negative rate. Login to comment

[hide] Genetic testing of sperm donors for cystic fibrosi... Eur J Obstet Gynecol Reprod Biol. 2013 Sep;170(1):183-7. doi: 10.1016/j.ejogrb.2013.06.022. Epub 2013 Jul 15. Landaburu I, Gonzalvo MC, Clavero A, Ramirez JP, Yoldi A, Mozas J, Zamora S, Martinez L, Castilla JA
Genetic testing of sperm donors for cystic fibrosis and spinal muscular atrophy: evaluation of clinical utility.
Eur J Obstet Gynecol Reprod Biol. 2013 Sep;170(1):183-7. doi: 10.1016/j.ejogrb.2013.06.022. Epub 2013 Jul 15., [PMID:23866907]

Abstract [show]
OBJECTIVE: To evaluate the clinical utility of genetic testing for cystic fibrosis (CF) and spinal muscular atrophy (SMA) in sperm donors. STUDY DESIGN: We studied the results of the genetic tests for CF and SMA applied to 372 sperm donor candidates. The CF carrier screening test analysed 32 mutations on the CFTR gene. Regarding SMA, the carrier test studied possible deletions of SMN1/2 by Multiplex Ligation-dependent Probe Amplification (MLPA) methodology. RESULTS: The carrier frequency obtained was greater for SMA than for CF. After adjusting the results obtained for the sensitivity of the tests, and taking into account the prevalence of female carriers in our population, the probability of transmission of the disease to the child from a donor with a negative genetic test was about five times lower in the case of SMA than in CF, although this difference was not statistically significant. The number of donors needed to screen (NNS) to avoid the occurrence of a child being affected by CF and SMA in our population was similar in both cases (1591 vs. 1536). CONCLUSIONS: This study demonstrates the need to include SMA among the diseases for which genetic screening is performed in the process of sperm donor selection. We believe that testing donors for SMA is as important and as useful as doing so for CF.

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51 The panel of mutations studied was: S549N, S549R, R553X, G551D, V520F, I507del, F508del, 3876delA, 1717-1G->A, G542X, R560T, 3120+1G->A, A455E, R117H, 394delTT, 2183AA- >G, 2184delA, 2789+5G->A, 1898+1G->A, 621+1G->T, 711+1G- >T, G85E, R347P, R347H, W1282X, R334W, 1078delT, 3849+10kbC->T, R1162X, N1303K, 3659delC, 3905insT. Login to comment

[hide] Effect of ivacaftor on CFTR forms with missense mu... J Cyst Fibros. 2014 Jan;13(1):29-36. doi: 10.1016/j.jcf.2013.06.008. Epub 2013 Jul 23. Van Goor F, Yu H, Burton B, Hoffman BJ
Effect of ivacaftor on CFTR forms with missense mutations associated with defects in protein processing or function.
J Cyst Fibros. 2014 Jan;13(1):29-36. doi: 10.1016/j.jcf.2013.06.008. Epub 2013 Jul 23., [PMID:23891399]

Abstract [show]
BACKGROUND: Ivacaftor (KALYDECO, VX-770) is a CFTR potentiator that increased CFTR channel activity and improved lung function in patients age 6 years and older with CF who have the G551D-CFTR gating mutation. The aim of this in vitro study was to evaluate the effect of ivacaftor on mutant CFTR protein forms with defects in protein processing and/or channel function. METHODS: The effect of ivacaftor on CFTR function was tested in electrophysiological studies using a panel of Fischer rat thyroid (FRT) cells expressing 54 missense CFTR mutations that cause defects in the amount or function of CFTR at the cell surface. RESULTS: Ivacaftor potentiated multiple mutant CFTR protein forms that produce functional CFTR at the cell surface. These included mutant CFTR forms with mild defects in CFTR processing or mild defects in CFTR channel conductance. CONCLUSIONS: These in vitro data indicated that ivacaftor is a broad acting CFTR potentiator and could be used to help stratify patients with CF who have different CFTR genotypes for studies investigating the potential clinical benefit of ivacaftor.

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39 However, a significantly higher level (P b 0.05; ANOVA followed by Tukey's multiple comparisons test; n = 3-6) of mRNA expression was measured for P67L-, E92K-, and A455E-CFTR (Fig. 1). Login to comment
43 Mutations such as P67L-, E56K-, and A455E-CFTR exhibited intermediate levels of mature CFTR, which are consistent with less severe defects in CFTR processing (mature CFTR protein for P67L-, E56K-, and A455E-CFTR were 28.4&#b1; 6.8, 12.2&#b1;1.5, and 11.5&#b1;2.5% of normal, respectively). Login to comment
44 None M1V A46D E56K P67L R74W G85E E92K D110E D110H R117C R117H E193K L206W R334W I336K T338I S341P R347H R347P R352Q A455E L467P S492F F508del V520F A559T R560S R560T A561E Y569D D579G R668C L927P S945L S977F L997F F1052V H1054D K1060T L1065P R1066C R1066H R1066M A1067T R1070Q R1070W F1074L L1077P H1085R M1101K D1152H S1235R D1270N N1303K 0 100 200 300 400 500 600 * * * CFTR Mutation mRNA (% Normal CFTR) Fig. 1. Login to comment
64 Mutant CFTR form CFTR processing Mature/total % Normal CFTR Normal 0.89 &#b1; 0.01 100.0 &#b1; 18.5 G85E -0.05 &#b1; 0.04 -1.0 &#b1; 0.9 R560S 0.00 &#b1; 0.00 0.0 &#b1; 0.0 R1066C 0.02 &#b1; 0.01 0.0 &#b1; 0.0 S492F 0.00 &#b1; 0.00 0.1 &#b1; 0.1 R560T 0.01 &#b1; 0.01 0.2 &#b1; 0.1 V520F 0.05 &#b1; 0.03 0.3 &#b1; 0.2 M1101K 0.05 &#b1; 0.03 0.3 &#b1; 0.1 A561E 0.08 &#b1; 0.04 0.5 &#b1; 0.2 R1066M 0.02 &#b1; 0.02 0.5 &#b1; 0.4 N1303K 0.02 &#b1; 0.02 0.5 &#b1; 0.3 A559T 0.16 &#b1; 0.09 0.6 &#b1; 0.2 M1V 0.06 &#b1; 0.06 0.7 &#b1; 0.6 Y569D 0.11 &#b1; 0.04 0.6 &#b1; 0.2 R1066H 0.08 &#b1; 0.02a 0.7 &#b1; 0.2a L1065P 0.05 &#b1; 0.05 1.0 &#b1; 0.8 L467P 0.10 &#b1; 0.07 1.2 &#b1; 0.8 L1077P 0.08 &#b1; 0.04 1.5 &#b1; 0.6 A46D 0.21 &#b1; 0.08 1.9 &#b1; 0.5a E92K 0.06 &#b1; 0.05 1.9 &#b1; 1.3 H1054D 0.09 &#b1; 0.04 1.9 &#b1; 0.8 F508del 0.09 &#b1; 0.02a 2.3 &#b1; 0.5a H1085R 0.06 &#b1; 0.01a 3.0 &#b1; 0.7a I336K 0.42 &#b1; 0.05a 6.5 &#b1; 0.7a L206W 0.35 &#b1; 0.10a 6.8 &#b1; 1.7a F1074L 0.52 &#b1; 0.03a 10.9 &#b1; 0.6a A455E 0.26 &#b1; 0.10a 11.5 &#b1; 2.5a E56K 0.29 &#b1; 0.04a 12.2 &#b1; 1.5a R347P 0.48 &#b1; 0.04a 14.6 &#b1; 1.8a R1070W 0.61 &#b1; 0.04a 16.3 &#b1; 0.6a P67L 0.36 &#b1; 0.04a 28.4 &#b1; 6.8a R1070Q 0.90 &#b1; 0.01a 29.5 &#b1; 1.4a S977F 0.97 &#b1; 0.01a 37.3 &#b1; 2.4a A1067T 0.78 &#b1; 0.03a 38.6 &#b1; 6.1a D579G 0.72 &#b1; 0.02a 39.3 &#b1; 3.1a D1270N 1.00 &#b1; 0.00a,c 40.7 &#b1; 1.2a S945L 0.65 &#b1; 0.04a 42.4 &#b1; 8.9a L927P 0.89 &#b1; 0.01a,b 43.5 &#b1; 2.5a,b R117C 0.87 &#b1; 0.02a,b 49.1 &#b1; 2.9a,b T338I 0.93 &#b1; 0.03a,b 54.2 &#b1; 3.7a,b L997F 0.90 &#b1; 0.04a,b 59.8 &#b1; 10.4a,b D110H 0.97 &#b1; 0.01a,b 60.6 &#b1; 1.5a,b S341P 0.79 &#b1; 0.02a 65.0 &#b1; 4.9a,b R668C 0.94 &#b1; 0.03a,b 68.5 &#b1; 1.9a,b R74W 0.78 &#b1; 0.01a 69.0 &#b1; 2.7a,b D110E 0.92 &#b1; 0.05a,b 87.5 &#b1; 9.5a,b R334W 0.91 &#b1; 0.05a,b 97.6 &#b1; 10.0a,b K1060T 0.87 &#b1; 0.02a,b 109.9 &#b1; 28.0a,b R347H 0.96 &#b1; 0.02a,c 120.7 &#b1; 2.8a,b S1235R 0.96 &#b1; 0.00a,c 139.0 &#b1; 9.0a,b E193K 0.84 &#b1; 0.02a,b 143.0 &#b1; 17.1a,b R117H 0.86 &#b1; 0.01a,b 164.5 &#b1; 34.2a,b R352Q 0.98 &#b1; 0.01a,b 179.9 &#b1; 8.0a,c F1052V 0.90 &#b1; 0.01a,b 189.9 &#b1; 33.1a,b D1152H 0.96 &#b1; 0.02a,c 312.0 &#b1; 45.5a,b Notes to Table 1: Quantification of steady-state CFTR maturation expressed as the mean (&#b1;SEM; n = 5-9) ratio of mature CFTR to total CFTR (immature plus mature) or level of mature mutant CFTR relative to mature normal-CFTR (% normal CFTR) in FRT cells individually expressing CFTR mutations. Login to comment
74 Because the level of CFTR mRNA was similar across the panel of cell lines tested, the range in baseline activity and ivacaftor response likely reflects the severity of the functional defect and/or the 0 50 100 150 200 S341P R347P L467P S492F A559T A561E Y569D L1065P R1066C R1066M L1077P M1101K N1303K R560S L927P R560T H1085R V520F E92K M1V F508del H1054D I336K A46D G85E R334W T338I R1066H R352Q R117C L206W R347H S977F S945L A455E F1074L E56K P67L R1070W D110H D579G D110E R1070Q L997F A1067T E193K R117H R74W K1060T R668C D1270N D1152H S1235R F1052V Baseline With ivacaftor * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Chloride transport (% Normal) Mutant CFTR form 0 100 200 300 400 S341P R347P L467P S492F A559T A561E Y569D L1065P R1066C R1066M L1077P M1101K N1303K R560S L927P R560T H1085R V520F E92K M1V F508del H1054D I336K A46D G85E R334W T338I R1066H R352Q R117C L206W R347H S977F S945L A455E F1074L P67L E56K R1070W D110H D579G D110E R1070Q L997F A1067T E193K R117H R74W K1060T R668C D1270N D1152H S1235R F1052V * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Mature CFTR (% Normal) Mutant CFTR form A B Fig. 2. Login to comment
82 Mutation Patientsa Chloride transport (bc;A/cm2 ) Chloride transport (% normal) EC50 Baseline With ivacaftor Baseline With ivacaftor Fold increase over baselineb Normal 204.5 &#b1; 33.3 301.3 &#b1; 33.8c 100.0 &#b1; 16.3 147.3 &#b1; 16.5c 1.5 266 &#b1; 42 G551D 1282 1.5 &#b1; 0.7 113.2 &#b1; 13.0c 1.0 &#b1; 0.5 55.3 &#b1; 6.3c 55.3 312 &#b1; 73 F1052V 12 177.3 &#b1; 13.7 410.2 &#b1; 11.3c 86.7 &#b1; 6.7 200.7 &#b1; 5.6c 2.3 177 &#b1; 14 S1235R ND 160.6 &#b1; 25.7 352.1 &#b1; 43.4c 78.5 &#b1; 12.6 172.2 &#b1; 21.2c 2.2 282 &#b1; 104 D1152H 185 117.3 &#b1; 23.0 282.7 &#b1; 46.9c 57.4 &#b1; 11.2 138.2 &#b1; 22.9c 2.4 178 &#b1; 67 D1270N 32 109.5 &#b1; 20.5 209.5 &#b1; 27.4c 53.6 &#b1; 10.0 102.4 &#b1; 13.4c 1.9 254 &#b1; 56 R668C 45 99.0 &#b1; 9.4 217.6 &#b1; 11.7c 48.4 &#b1; 4.6 106.4 &#b1; 5.7c 2.2 517 &#b1; 105 K1060T ND 89.0 &#b1; 9.8 236.4 &#b1; 20.3c 43.5 &#b1; 4.8 115.6 &#b1; 9.9c 2.7 131 &#b1; 73 R74W 25 86.8 &#b1; 26.9 199.1 &#b1; 16.8c 42.5 &#b1; 13.2 97.3 &#b1; 8.2c 2.3 162 &#b1; 17 R117H 739 67.2 &#b1; 13.3 274.1 &#b1; 32.2c 32.9 &#b1; 6.5 134.0 &#b1; 15.7c 4.1 151 &#b1; 14 E193K ND 62.2 &#b1; 9.8 379.1 &#b1; 1.1c 30.4 &#b1; 4.8 185.4 &#b1; 1.0c 6.1 240 &#b1; 20 A1067T ND 55.9 &#b1; 3.2 164.0 &#b1; 9.7c 27.3 &#b1; 1.6 80.2 &#b1; 4.7c 2.9 317 &#b1; 214 L997F 27 43.7 &#b1; 3.2 145.5 &#b1; 4.0c 21.4 &#b1; 1.6 71.2 &#b1; 2.0c 3.3 162 &#b1; 12 R1070Q 15 42.0 &#b1; 0.8 67.3 &#b1; 2.9c 20.6 &#b1; 0.4 32.9 &#b1; 1.4c 1.6 164 &#b1; 20 D110E ND 23.3 &#b1; 4.7 96.4 &#b1; 15.6c 11.4 &#b1; 2.3 47.1 &#b1; 7.6c 4.1 213 &#b1; 51 D579G 21 21.5 &#b1; 4.1 192.0 &#b1; 18.5c 10.5 &#b1; 2.0 93.9 &#b1; 9.0c 8.9 239 &#b1; 48 D110H 30 18.5 &#b1; 2.2 116.7 &#b1; 11.3c 9.1 &#b1; 1.1 57.1 &#b1; 5.5c 6.2 249 &#b1; 59 R1070W 13 16.6 &#b1; 2.6 102.1 &#b1; 3.1c 8.1 &#b1; 1.3 49.9 &#b1; 1.5c 6.2 158 &#b1; 48 P67L 53 16.0 &#b1; 6.7 88.7 &#b1; 15.7c 7.8 &#b1; 3.3 43.4 &#b1; 7.7c 5.6 195 &#b1; 40 E56K ND 15.8 &#b1; 3.1 63.6 &#b1; 4.4c 7.7 &#b1; 1.5 31.1 &#b1; 2.2c 4.0 123 &#b1; 33 F1074L ND 14.0 &#b1; 3.4 43.5 &#b1; 5.4c 6.9 &#b1; 1.6 21.3 &#b1; 2.6c 3.1 141 &#b1; 19 A455E 120 12.9 &#b1; 2.6 36.4 &#b1; 2.5c 6.3 &#b1; 1.2 17.8 &#b1; 1.2c 2.8 170 &#b1; 44 S945L 63 12.3 &#b1; 3.9 154.9 &#b1; 47.6c 6.0 &#b1; 1.9 75.8 &#b1; 23.3c 12.6 181 &#b1; 36 S977F 9 11.3 &#b1; 6.2 42.5 &#b1; 19.1c 5.5 &#b1; 3.0 20.8 &#b1; 9.3c 3.8 283 &#b1; 36 R347H 65 10.9 &#b1; 3.3 106.3 &#b1; 7.6c 5.3 &#b1; 1.6 52.0 &#b1; 3.7c 9.8 280 &#b1; 35 L206W 81 10.3 &#b1; 1.7 36.4 &#b1; 2.8c 5.0 &#b1; 0.8 17.8 &#b1; 1.4c 3.6 101 &#b1; 13 R117C 61 5.8 &#b1; 1.5 33.7 &#b1; 7.8c 2.9 &#b1; 0.7 16.5 &#b1; 3.8c 5.7 380 &#b1; 136 R352Q 46 5.5 &#b1; 1.0 84.5 &#b1; 7.8c 2.7 &#b1; 0.5 41.3 &#b1; 3.8c 15.2 287 &#b1; 75 R1066H 29 3.0 &#b1; 0.3 8.0 &#b1; 0.8c 1.5 &#b1; 0.1 3.9 &#b1; 0.4c 2.6 390 &#b1; 179 T338I 54 2.9 &#b1; 0.8 16.1 &#b1; 2.4c 1.4 &#b1; 0.4 7.9 &#b1; 1.2c 5.6 334 &#b1; 38 R334W 150 2.6 &#b1; 0.5 10.0 &#b1; 1.4c 1.3 &#b1; 0.2 4.9 &#b1; 0.7c 3.8 259 &#b1; 103 G85E 262 1.6 &#b1; 1.0 1.5 &#b1; 1.2 0.8 &#b1; 0.5 0.7 &#b1; 0.6 NS NS A46D ND 2.0 &#b1; 0.6 1.1 &#b1; 1.1 1.0 &#b1; 0.3 0.5 &#b1; 0.6 NS NS I336K 29 1.8 &#b1; 0.2 7.4 &#b1; 0.1c 0.9 &#b1; 0.1 3.6 &#b1; 0.1c 4 735 &#b1; 204 H1054D ND 1.7 &#b1; 0.3 8.7 &#b1; 0.3c 0.8 &#b1; 0.1 4.2 &#b1; 0.1c 5.3 187 &#b1; 20 F508del 29,018 0.8 &#b1; 0.6 12.1 &#b1; 1.7c 0.4 &#b1; 0.3 5.9 &#b1; 0.8c 14.8 129 &#b1; 38 M1V 9 0.7 &#b1; 1.4 6.5 &#b1; 1.9c 0.4 &#b1; 0.7 3.2 &#b1; 0.9c 8.0 183 &#b1; 85 E92K 14 0.6 &#b1; 0.2 4.3 &#b1; 0.8c 0.3 &#b1; 0.1 2.1 &#b1; 0.4c 7.0 198 &#b1; 46 V520F 58 0.4 &#b1; 0.2 0.5 &#b1; 0.2 0.2 &#b1; 0.1 0.2 &#b1; 0.1 NS NS H1085R ND 0.3 &#b1; 0.2 2.1 &#b1; 0.4 0.2 &#b1; 0.1 1.0 &#b1; 0.2 NS NS R560T 180 0.3 &#b1; 0.3 0.5 &#b1; 0.5 0.1 &#b1; 0.1 0.2 &#b1; 0.2 NS NS L927P 15 0.2 &#b1; 0.1 10.7 &#b1; 1.7c 0.1 &#b1; 0.1 5.2 &#b1; 0.8c 52.0 313 &#b1; 66 R560S ND 0.0 &#b1; 0.1 -0.2 &#b1; 0.2 0.0 &#b1; 0.0 -0.1 &#b1; 0.1 NS NS N1303K 1161 0.0 &#b1; 0.0 1.7 &#b1; 0.3 0.0 &#b1; 0.0 0.8 &#b1; 0.2 NS NS M1101K 79 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS L1077P 42 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R1066M ND 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R1066C 100 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS L1065P 25 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS Y569D 9 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS A561E ND 0.0 &#b1; 0.1 0.0 &#b1; 0.1 0.0 &#b1; 0.0 0.0 &#b1; 0.1 NS NS A559T 43 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS S492F 16 0.0 &#b1; 0.0 1.7 &#b1; 1.2 0.0 &#b1; 0.0 0.8 &#b1; 0.6 NS NS L467P 16 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R347P 214 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS S341P 9 0.0 &#b1; 0.0 0.2 &#b1; 0.2 0.0 &#b1; 0.0 0.1 &#b1; 0.1 NS NS a Number of individuals with the individual mutation in the CFTR-2 database (www.CFTR2.org). Login to comment
86 For example, the baseline level of chloride transport and ivacaftor response was higher for mutant CFTR forms associated with mild defects in CFTR processing (e.g., E56K, P67L, L206W, A455E, D579G, S945L, S977F, A1067T, R1070Q, R1070W, F1074L, and D1270N) than for those associated with severe defects in CFTR processing (e.g., F508del, H1054D, R1066H). Login to comment
92 Mutant CFTR forms that did not significantly respond to ivacaftor under the experimental conditions used in this study were generally associated with severe defects in CFTR processing A B C D E F 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 S1235R D1152H F1052V D1270N ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 R668C K1060T R74W R117H ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 E193K A1067T L997F R1070Q ivacaftor [Log M] Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 D110E D579G D110H R1070W ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 F1074L E56K P67L A455E ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 R347H S945L L206W S977F ivacaftor [Log M] 0 100 200 300 400 -8 -6 -4 0 T338I R1066H R117C R352Q ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 F508del R334W H1054D E92K ivacaftor [Log M] 0 5 10 15 20 -9 -8 -7 -6 -5 -4 0 F508del R334W H1054D E92K R1066H T338I ivacaftor [Log M] G H I Fig. 3. Login to comment

[hide] Sinonasal manifestations of cystic fibrosis: a cor... J Cyst Fibros. 2014 Jul;13(4):442-8. doi: 10.1016/j.jcf.2013.10.011. Epub 2013 Nov 5. Berkhout MC, van Rooden CJ, Rijntjes E, Fokkens WJ, el Bouazzaoui LH, Heijerman HG
Sinonasal manifestations of cystic fibrosis: a correlation between genotype and phenotype?
J Cyst Fibros. 2014 Jul;13(4):442-8. doi: 10.1016/j.jcf.2013.10.011. Epub 2013 Nov 5., [PMID:24210900]

Abstract [show]
BACKGROUND: Patients with Cystic Fibrosis are prone to develop sinonasal disease. Studies in genotype-phenotype correlations for sinonasal disease are scarce and inconclusive. METHODS: In this observational study several aspects of sinonasal disease were investigated in 104 adult patients with CF. In each patient a disease specific quality of life questionnaire (RSOM-31), nasal endoscopy and a CT scan of the paranasal sinuses were performed. Patients were divided into two groups, class I-III mutations and class IV-V mutations, based on their CFTR mutations. RESULTS: The prevalence of rhinosinusitis in adult patients with CF was 63% and the prevalence of nasal polyps 25%. Patients with class I-III mutations had significantly smaller frontal sinuses, sphenoid sinuses, more opacification in the sinonasal area and more often osteitis/neoosteogenesis of the maxillary sinus wall compared to patients with class IV and V mutations. CONCLUSION: These data suggest more severe sinonasal disease in patients with class I-III mutations compared to patients with class IV-V mutations.

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163 Genotype Frequency; N (%) Class of mutation F508del/F508del 61 (58.7) I-III F508del/3849 + 10kbC 2 (1.9) IV-V F508del/N1303K 2 (1.9) I-III F508del/R1162X 2 (1.9) I-III F508del/A455E 12 (11.5) IV-V F508del/3272-26A N G 5 (4.8) IV-V F508del/E528X 1 (1.0) I-III F508del/S1251N 3 (2.9) IV-V F508del/R75Q 1 (1.0) IV-V F508del/G542X 2 (1.9) I-III F508del/1717-1G N A 1 (1.0) I-III F508del/Ser489X 1 (1.0) I-III F508del/4382delA 1 (1.0) -a F508del/L1077 1 (1.0) I-III F508del/1813insC 1 (1.0) -b A455E/S1251N 1 (1.0) IV-V A455E/E60X 1 (1.0) IV-V 3272-26A N G/G970R 1 (1.0) IV-V 3272-26A N G/R1162X 1 (1.0) IV-V F508del/UNK 2 (1.9) -c R117H-7T/UNK 1 (1.0) -d UNK/UNK 1 (1.0) -e Total 104 (100.4) One patient with pancreatic sufficiency and diagnosed at 46 years of age (class IV-V). Login to comment

[hide] Cost effectiveness of newborn screening for cystic... J Cyst Fibros. 2014 May;13(3):267-74. doi: 10.1016/j.jcf.2013.10.012. Epub 2013 Nov 12. Nshimyumukiza L, Bois A, Daigneault P, Lands L, Laberge AM, Fournier D, Duplantie J, Giguere Y, Gekas J, Gagne C, Rousseau F, Reinharz D
Cost effectiveness of newborn screening for cystic fibrosis: a simulation study.
J Cyst Fibros. 2014 May;13(3):267-74. doi: 10.1016/j.jcf.2013.10.012. Epub 2013 Nov 12., [PMID:24238947]

Abstract [show]
BACKGROUND: Early detection of cystic fibrosis (CF) by newborn screening (NBS) reduces the rate of avoidable complications. NBS protocols vary by jurisdiction and the cost effectiveness of these different protocols is debated. OBJECTIVE: To compare the cost effectiveness of various CF NBS options. METHODS: A Markov model was built to simulate the cost effectiveness of various CF-NBS options for a hypothetical CF-NBS program over a 5-year time horizon assuming its integration into an existing universal NBS program. NBS simulated options were based on a combination of tests between the two commonly used immunoreactive trypsinogen (IRT) cutoffs (96th percentile and 99.5th percentile) as first tier tests, and, as a second tier test, either a second IRT, pancreatic-associated protein (PAP) or CFTR mutation panels. CFTR mutation panels were also considered as an eventual third tier test. Data input parameters used were retrieved from a thorough literature search. Outcomes considered were the direct costs borne by the Quebec public health care system and the number of cases of CF detected through each strategy, including the absence of screening option. RESULTS: IRT-PAP with an IRT cutoff at the 96th percentile is the most favorable option with a ratio of CAD$28,432 per CF case detected. The next most favorable alternative is the IRT1-IRT2 option with an IRT1 cutoff at the 96th percentile. The no-screening option is dominated by all NBS screening protocols considered. Results were robust in sensitivity analyses. CONCLUSION: This study suggests that NBS for cystic fibrosis is a cost-effective strategy compared to the absence of NBS. The IRT-PAP newborn screening algorithm with an IRT cutoff at the 96th percentile is the most cost effective NBS approach for Quebec.

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162 For example, the A455E mutation is more common (around 3%) in Quebec [48] and has been reported as a false negative for PAP results. Login to comment

[hide] Cystic fibrosis carrier screening in a North Ameri... Genet Med. 2014 Jul;16(7):539-46. doi: 10.1038/gim.2013.188. Epub 2013 Dec 19. Zvereff VV, Faruki H, Edwards M, Friedman KJ
Cystic fibrosis carrier screening in a North American population.
Genet Med. 2014 Jul;16(7):539-46. doi: 10.1038/gim.2013.188. Epub 2013 Dec 19., [PMID:24357848]

Abstract [show]
PURPOSE: The aim of this study was to compare the mutation frequency distribution for a 32-mutation panel and a 69-mutation panel used for cystic fibrosis carrier screening. Further aims of the study were to examine the race-specific detection rates provided by both panels and to assess the performance of extended panels in large-scale, population-based cystic fibrosis carrier screening. Although genetic screening for the most common CFTR mutations allows detection of nearly 90% of cystic fibrosis carriers, the large number of other mutations, and their distribution within different ethnic groups, limits the utility of general population screening. METHODS: Patients referred for cystic fibrosis screening from January 2005 through December 2010 were tested using either a 32-mutation panel (n = 1,601,308 individuals) or a 69-mutation panel (n = 109,830). RESULTS: The carrier frequencies observed for the 69-mutation panel study population (1/36) and Caucasian (1/27) and African-American individuals (1/79) agree well with published cystic fibrosis carrier frequencies; however, a higher carrier frequency was observed for Hispanic-American individuals (1/48) using the 69-mutation panel as compared with the 32-mutation panel (1/69). The 69-mutation panel detected ~20% more mutations than the 32-mutation panel for both African-American and Hispanic-American individuals. CONCLUSION: Expanded panels using race-specific variants can improve cystic fibrosis carrier detection rates within specific populations. However, it is important that the pathogenicity and the relative frequency of these variants are confirmed.

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63 This threshold could not be reached Table 1ߒ CFTR allele frequency identified by the CF32 mutation panel Varianta Number of detected alleles Mutation (%) Legacy nomenclature HGVS nomenclature F508delb p.F508del 31,142 68.69 R117Hb p.R117H 5,198 11.46 G542Xb p.G542X 1,162 2.56 G551Db p.G551D 989 2.18 W1282Xb p.W1282X 824 1.82 3120ߙ+ߙ1G>Ab c.2988ߙ+ߙ1G>A 706 1.56 N1303Kb p.N1303K 648 1.43 R553Xb p.R553X 487 1.07 3849ߙ+ߙ10kbC>Tb c.3717ߙ+ߙ12191C>T 436 0.96 621ߙ+ߙ1G>Tb c.489ߙ+ߙ1G>T 410 0.90 1717-1G>Ab c.1585-1G>A 388 0.86 2789ߙ+ߙ5G>Ab c.2657ߙ+ߙ5G>A 382 0.84 I507delb p.I507del 258 0.57 R334Wb p.R334W 257 0.57 R1162Xb p.R1162X 211 0.47 G85Eb p.G85E 199 0.44 1898ߙ+ߙ1G>Ab c.1766ߙ+ߙ1G>A 170 0.37 R347Hc p.R347H 160 0.35 3659delCb c.3528delC 155 0.34 3876delAc c.3744delA 153 0.34 R560Tb p.R560T 132 0.29 S549Nc p.S549N 125 0.28 3905insTc c.3773dupT 121 0.27 R347Pb p.R347P 117 0.26 2184delAb c.2052delA 107 0.24 A455Eb p.A455E 106 0.23 711ߙ+ߙ1G>Tb c.579ߙ+ߙ1G>T 65 0.14 394delTTc c.262_263delTT 56 0.12 V520Fc p.V520F 54 0.12 1078delTc c.948delT 52 0.11 2183AA>Ga,c c.2051_2052delAAinsG 37 0.08 S549Rc p.S549R 31 0.07 Total 45,338 100 a 2183AA>G variant was added to the panel in 2010. b Variants from ACMG/ACOG CF screening panel. c Classified as a CF-causing mutation by the CFTR2 Database. ACMG, American College of Medical Genetics and Genomics; ACOG, American College of Obstetricians and Gynecologists; CF, cystic fibrosis; HGVS, Human Genome Variation Society. Table 2ߒ Continued on next page Table 2ߒ CFTR allele frequency identified by the CF69 mutation panel Varianta Allele frequency Mutation (%) Legacy nomenclature HGVS nomenclature F508delb p.F508del 1,868 60.49 R117Hb p.R117H 274 8.87 D1152Hc p.D1152H 125 4.05 G542Xb p.G542X 98 3.17 L206Wd p.L206W 73 2.36 3120ߙ+ߙ1G>Ab c.2988ߙ+ߙ1G>A 65 2.10 G551Db p.G551D 47 1.52 N1303Kb p.N1303K 42 1.36 W1282Xb p.W1282X 38 1.23 3849ߙ+ߙ10kbC>Tb c.3717ߙ+ߙ12191C>T 28 0.91 3876delAd c.3744delA 28 0.91 F311dele p.F312del 24 0.78 I507delb p.I507del 24 0.78 R553Xb p.R553X 24 0.78 R117Cd p.R117C 22 0.71 621ߙ+ߙ1G>Tb c.489ߙ+ߙ1G>T 21 0.68 1717-1G>Ab c.1585-1G>A 18 0.58 S549Nd p.S549N 18 0.58 R334Wb p.R334W 17 0.55 2789ߙ+ߙ5G>Ab c.2657ߙ+ߙ5G>A 16 0.52 G85Eb p.G85E 14 0.45 3199del6e c.3067_3072delATAGTG 12 0.39 R1066Cd p.R1066C 11 0.36 1898ߙ+ߙ1G>Ab c.1766ߙ+ߙ1G>A 10 0.32 R347Hd p.R347H 10 0.32 R1162 Xb p.R1162X 9 0.29 W1089Xd p.W1089X 9 0.29 2184delAb c.2052delA 8 0.26 2307insAd c.2175dupA 8 0.26 1078delTd c.948delT 7 0.23 R75Xd p.R75X 7 0.23 3120G>Ad c.2988 G>A 6 0.19 3659delCb c.3528delC 6 0.19 Q493Xd p.Q493X 6 0.19 R1158Xd p.R1158X 6 0.19 R560Tb p.R560T 6 0.19 1812-1G>Ad c.1680-1G>A 5 0.16 2055del9>Ad c.1923_1931del9insA 5 0.16 406-1G>Ad c.274-1G>A 5 0.16 A559Td p.A559T 5 0.16 R347Pb p.R347P 5 0.16 S1255Xd p.S1255X 5 0.16 1677delTAd c.1545_1546delTA 4 0.13 711ߙ+ߙ1G>Tb c.579ߙ+ߙ1G>T 4 0.13 E60Xd p.E60X 4 0.13 R352Qd p.R352Q 4 0.13 Y1092Xd p.Y1092X 4 0.13 2183AA>Gd c.2051_2052delAAinsG 3 0.10 3791delCd c.3659delC 3 0.10 3905insTd c.3773dupT 3 0.10 by 10 variants: the 2143delT, A455E, S549R, Y122X, and M1101K mutations, typically observed in Caucasians; 935delA, 2869insG, and Q890X in Hispanics; and 405+3A>C and G480C in the African-American population. Login to comment
66 The low frequency of the A455E mutation (0.07%) from the ACMG/ACOG panel may be explained by patient preselection through the use of the 32-mutation panel, or random drift. Login to comment
80 The Table 3ߒ Frequency of 5T/7T/9T genotypes as a result of R117H reflex testing Poly-T alleles Number of detected alleles (%) CF32 panel CF69 panel 5T/5T 23 (0.44) 2 (0.73) 5T/7T 430 (8.27) 26 (9.49) 5T/9T 38 (0.73) 1 (0.37) 7T/7T 4,103 (78.93) 219 (79.92) 7T/9T 604 (11.61) 26 (9.49) 9T/9T 1 (0.02) 0 Total 5,198 (100) 274 (100) 394delTTd c.262_263delTT 3 0.10 G178Rd p.G178R 3 0.10 V520Fd p.V520F 3 0.10 2143delTd c.2012delT 2 0.06 935delAe c.803delA 2 0.06 A455Eb p.A455E 2 0.06 Q890Xd p.Q890X 2 0.06 S549Rd p.S549R 2 0.06 2869insGd c.2737insG 1 0.03 405ߙ+ߙ3A>Ce c.273ߙ+ߙ3A>C 1 0.03 G480Ce p.G480C 1 0.03 M1101Kd p.M1101K 1 0.03 Y122Xd p.Y122X 1 0.03 Total 3,088 100 a 1898ߙ+ߙ5G>Te , 444delA, G330X, S364Pe , K710X, and S1196X mutations were not detected in the target population. Login to comment

[hide] Correcting the cystic fibrosis disease mutant, A45... PLoS One. 2014 Jan 8;9(1):e85183. doi: 10.1371/journal.pone.0085183. eCollection 2014. Cebotaru L, Rapino D, Cebotaru V, Guggino WB
Correcting the cystic fibrosis disease mutant, A455E CFTR.
PLoS One. 2014 Jan 8;9(1):e85183. doi: 10.1371/journal.pone.0085183. eCollection 2014., [PMID:24416359]

Abstract [show]
Cystic fibrosis is caused by more than 1000 mutations, the most common being the DeltaF508 mutation. These mutations have been divided into five classes [1], with DeltaF508 CFTR in class II. Here we have studied the class V mutation A455E. We report that the mature and immature bands of A455E are rapidly degraded primarily by proteasomes; the short protein half-life of this mutant therefore resembles that of DeltaF508 CFTR. A455E could be rescued by treatment of the cells with proteasome inhibitors. Furthermore, co-transfection of A455E with the truncation mutant Delta264 CFTR also rescued the mature C band, indicating that A455E can be rescued by transcomplementation. We found that Delta264 CFTR bound to A455E, forming a bimolecular complex. Treatment with the compound correctors C3 and C4 also rescued A455E. These results are significant because they show that although DeltaF508 belongs to a different class than A455E, it can be rescued by the same strategies, offering therapeutic promise to patients with Class V mutations.

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0 Correcting the Cystic Fibrosis Disease Mutant, A455E CFTR Liudmila Cebotaru1,2 , Daniele Rapino1,2 , Valeriu Cebotaru3 , William B. Guggino2 * 1 Department of Ophthalmology, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States of America, 2 Department of Physiology, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States of America, 3 Department of Medicine, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States of America Abstract Cystic fibrosis is caused by more than 1000 mutations, the most common being the DF508 mutation. Login to comment
2 Here we have studied the class V mutation A455E. Login to comment
3 We report that the mature and immature bands of A455E are rapidly degraded primarily by proteasomes; the short protein half-life of this mutant therefore resembles that of DF508 CFTR. Login to comment
4 A455E could be rescued by treatment of the cells with proteasome inhibitors. Login to comment
5 Furthermore, co-transfection of A455E with the truncation mutant D264 CFTR also rescued the mature C band, indicating that A455E can be rescued by transcomplementation. Login to comment
6 We found that D264 CFTR bound to A455E, forming a bimolecular complex. Login to comment
7 Treatment with the compound correctors C3 and C4 also rescued A455E. Login to comment
8 These results are significant because they show that although DF508 belongs to a different class than A455E, it can be rescued by the same strategies, offering therapeutic promise to patients with Class V mutations. Login to comment
9 Citation: Cebotaru L, Rapino D, Cebotaru V, Guggino WB (2014) Correcting the Cystic Fibrosis Disease Mutant, A455E CFTR. Login to comment
26 One of these class V mutations is A455E. Login to comment
27 The A455E mutation is located in NBD1. Login to comment
30 Thus, because the mild disease resulting from A455E is thought to arise from reduced protein expression, it is considered a class V mutation. Login to comment
31 Thus, an effective pharmacological approach to treating this mutation should involve increasing the protein levels of A455E. Login to comment
35 The purpose of the current study was to determine whether analogous transcomplementation can be used to enhance the protein processing of A455E. Login to comment
37 Plasmids and constructs The construct pEGFP A455E was a gift from Dr. Gary Cutting at Johns Hopkins U. Login to comment
49 A455E has reduced expression of mature CFTR. Login to comment
50 Cos7 cells were transfected with 2 mg of wild-type, A455E, or DF508 CFTR constructs. Login to comment
52 Note that there is much less mature C band in the A455E sample than in the wild-type sample. Login to comment
53 In this and subsequent blots, some mature C band was detected with A455E (n = 8). Login to comment
56 Cells transfected with A455E cDNA were treated either with MG132, a more general inhibitor (n = 6) (A, B), or the more specific inhibitor of proteasomes, PS341 (n = 2) (C). Login to comment
57 Note that in both cases, proteasome inhibition caused an increase in both the immature B and mature C bands of A455E. Login to comment
58 doi:10.1371/journal.pone.0085183.g002 Results Expression of A455E When we compared the expression of the A455E mutant to that of both wild-type and nF508 CFTR (Fig. 1) by western blotting, we found that the amount of CFTR protein was greatly reduced in the Cos7 cells transfected with the A455E mutant. Login to comment
59 To evaluate the degradation of A455E CFTR, we treated the cells with MG132, a non-specific inhibitor of proteasomal degradation. Login to comment
60 Fig. 2 shows that in the presence of MG132, the protein expression of both the B and C bands of A455E CFTR increased dramatically. Login to comment
62 PS341 also caused an increase in both the B and C bands of A455E. Login to comment
63 Furthermore, we noted that A455E could be rescued by growing the cells at a reduced temperature, as had previously been observed for DF508 [13]. Login to comment
64 In sharp contrast, there was no increase in the protein expression of A455E CFTR when the cells were treated with the aggresome inhibitor tubacin or the lysosomal inhibitor E64 (Fig. 3). Login to comment
65 These data suggest that A455E is degraded primarily in proteasomes. Login to comment
66 To evaluate how rapidly the A455E CFTR protein is degraded, we treated the transfected cells with cycloheximide for between 1 and 7 hours (Fig 4). Login to comment
67 Surprisingly, both the B and C bands of A455E CFTR rapidly disappeared in the cells treated with cycloheximide (Fig. 4), suggesting that it is rapidly degraded, as is DF508 CFTR (see [13]). Login to comment
68 n264 CFTR increases the processing of band B to band C of A455E CFTR We then tested whether the truncation mutant, n264 CFTR, was capable of transcomplementation with A455E (Fig. 5). Login to comment
69 In order to determine whether D264 CFTR affects the maturation of A455E CFTR, we cotransfected D264 CFTR and A455E CFTR into Cos7 cells and found that the mature C band from A455E CFTR was increased in cells cotransfected with D264 CFTR, as compared to cells transfected with A455E cDNA alone (Fig. 5). Login to comment
72 Cos7 cells were transfected with A455E CFTR cDNA and treated for 16 h with the lysosome inhibitor E64 (n = 4) (A) There was very little change in band density in any of the treated groups or in the presence of the inhibitors when compared to the control or the HDAC6 inhibitor tubacin to inhibit aggresomes (n = 3) (B, C). Login to comment
74 doi:10.1371/journal.pone.0085183.g003 n264 CFTR binds to A455E CFTR, forming a biomolecular complex We and others have shown that transcomplementation can occur via direct binding of truncated forms of CFTR to DF508-CFTR and via chaperone displacement [17]. Login to comment
75 In order to assess these possibilities in A455E CFTR, we conducted co-immunpre- cipitation experiments. Login to comment
76 Fig. 6 shows that D264-CFTR did indeed bind to A455E, in both the absence and presence of the proteasome inhibitor MG123. Login to comment
77 Correctors 4A (C4) and VX325 (C3) increase the processing of band B to band C of A455E CFTR We next asked whether small-molecule correctors might be effective in rescuing A455E CFTR (Fig. 7). Login to comment
79 We found that corrector C4 does have a robust effect on A455E CFTR; in contrast, C3 had only a minimal effect on A455E (Fig. 7). Login to comment
83 Here we show that A455E can also be rescued by transcomplementation. Login to comment
87 The A455E mutation, on the other hand, is located within the F1-type ATP-binding core subdomain near to the ABC protein signature, the Walker A domain [24]. Login to comment
88 Given the proximity to the Walker A domain, one might expect that A455E would have alterations in gating. Login to comment
90 A455E also functions well as a regulator of other channels [25]. Login to comment
93 At least two studies have failed to detect mature band C from A455E [11,26], although the results of their electrophysiological studies suggested that some mature band C must have been present at the plasma membrane in order to generate chloride currents [11]. Login to comment
94 In our study, we do detect some mature band C at the plasma membrane, but when the cells are treated with cycloheximide to evaluate protein degradation, it is clear that the mature band C of A455E is rapidly degraded along with the immature B band. Login to comment
98 have shown that A455E has a pattern of degradation that is clearly different from that of DF508 CFTR. Login to comment
99 A455E appears to be proteolytically cleaved within the NBD1-R domain to form C-terminal aggregates. Login to comment
101 Clearly, these results show that the A455E mutant is distinctly different from DF508 CFTR. Login to comment
102 Nevertheless, A455E shows some similarity to DF508 CFTR. Login to comment
103 Although A455E is uniquely cleaved in the cytoplasm, our results show that it is still degraded in the proteasome, because treatment with two types of proteasome inhibitors led to significant increases in steady-state protein levels. Login to comment
104 In fact, we saw a rather large increase in the mature band of A455E after proteasome inhibition. Login to comment
105 This result is in contrast to the response of A455E to lysosomal inhibitors, which were without effect. Login to comment
107 A455E binds to n27-264 CFTR. Login to comment
108 Cos7 cells were transfected with both D27-264 CFTR and an A455E CFTR construct bearing a GFP tag. Login to comment
109 Anti-GFP antibodies were used to pull down A455E, and the gels were blotted with anti-CFTR antibody. Login to comment
113 Transcomplementation of A455E by D27-264 CFTR. Login to comment
114 Both the C and B bands of A455E CFTR were increased when cells were cotransfected with D27-264 CFTR, showing that A455E could be rescued by transcomplementation. Login to comment
117 Effect of protein synthesis inhibition on the degradation of A455E. Login to comment
118 Cos7 cells were transfected with A455E cDNA and treated with cycloheximide (25 mg/ml) for the indicated times. Login to comment
119 Note the rapid decay of both the mature C and immature B bands of A455E. Login to comment
122 Taken together, our data suggest that A455E, like DF508 CFTR, is processed by proteasomes. Login to comment
123 D264 CFTR rescues A455E and forms a molecular complex between the two molecules. Login to comment
126 It is possible that a similar interaction occurs between D264 and A455E. Login to comment
131 The observation that A455E is readily rescued by D264 CFTR suggests that transcomplementation may be influencing NBD1 in the region of the Walker sites. Login to comment
132 One then may ask why the interaction with the normal NBD2 of A455E does not rescue its own NBD1. Login to comment
138 Correctors can rescue A455E. Login to comment
139 Cos7 cells were transfected with A455E and treated with the correctors C3 or C4 for 16 h at the specified concentrations. Login to comment
140 Note that C4 had a profound effect on the immature B band of A455E as well as causing an increase in the mature C band (A, B). Login to comment
143 doi:10.1371/journal.pone.0085183.g007 Therapeutic transcomplementation to rescue A455E would require gene transfer via a virus or non-viral particle. Login to comment
150 Our demonstration that both C3 and C4 can rescue A455E suggests that A455E CFTR may be a better candidate for correction with either compound correctors or transcomplementation than is DF508 CFTR. Login to comment

[hide] The relative frequency of CFTR mutation classes in... J Cyst Fibros. 2014 Jul;13(4):403-9. doi: 10.1016/j.jcf.2013.12.003. Epub 2014 Jan 16. De Boeck K, Zolin A, Cuppens H, Olesen HV, Viviani L
The relative frequency of CFTR mutation classes in European patients with cystic fibrosis.
J Cyst Fibros. 2014 Jul;13(4):403-9. doi: 10.1016/j.jcf.2013.12.003. Epub 2014 Jan 16., [PMID:24440181]

Abstract [show]
More than 1900 different mutations in the CFTR gene have been reported. These are grouped into classes according to their effect on the synthesis and/or function of the CFTR protein. CFTR repair therapies that are mutation or mutation class specific are under development. To progress efficiently in the clinical phase of drug development, knowledge of the relative frequency of CFTR mutation classes in different populations is useful. Therefore, we describe the mutation class spectrum in 25,394 subjects with CF from 23 European countries. In 18/23 countries, 80% or more of the patients had at least one class II mutation, explained by F508del being by far the most frequent mutation. Overall 16.4% of European patients had at least one class I mutation but this varied from 3 countries with more than 30% to 4 countries with less than 10% of subjects. Overall only respectively 3.9, 3.3 and 3.0% of European subjects had at least one mutation of classes III, IV and V with again great variability: 14% of Irish patients had at least one class III mutation, 7% of Portuguese patients had at least one class IV mutation, and in 6 countries more than 5% of patients had at least one class V mutation.

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30 Finally, class V mutations result in a markedly decreased amount of CFTR protein with normal function at the epithelial cell membrane and include splice site mutations that only partially disturb correct splicing (e.g. 3849+10KbCNT and 2789+5GNA) or mutant CFTR that only partially matures (e.g. A455E). Login to comment
56 Class Type of defect List of mutations attributed to this class Class I Defective protein production Nonsense mutations Large deletions and insertions 1078delT; 1717-1G࢐A; 3659delC; 621+1G࢐T Class II Defective protein processing G85E, F508del, I507del, R560T, N1303K Class III Defective protein regulation ('gating`) G178R, S549N, S549R, G551D, G551S, G970R, G1244E, S1251N, S1255P, G1349D Class IV Defective protein conductance R117H, R334W, R347P Class V Reduced amount of functioning protein 2789+5G࢐A, 3849+10KbC࢐T, A455E Unclassified All other mutations, including those unknown. Login to comment

[hide] Neonatal screening for cystic fibrosis: comparing ... J Cyst Fibros. 2014 Jul;13(4):384-90. doi: 10.1016/j.jcf.2014.01.004. Epub 2014 Feb 7. Sarles J, Giorgi R, Berthezene P, Munck A, Cheillan D, Dagorn JC, Roussey M
Neonatal screening for cystic fibrosis: comparing the performances of IRT/DNA and IRT/PAP.
J Cyst Fibros. 2014 Jul;13(4):384-90. doi: 10.1016/j.jcf.2014.01.004. Epub 2014 Feb 7., [PMID:24513262]

Abstract [show]
BACKGROUND: French health authorities promoted a study on 553,167 newborns comparing the performances of IRT/DNA and IRT/PAP for CF newborn screening. METHODS: In parallel to IRT/DNA, PAP was assayed in newborns with IRT>50 mug/L. Provisional PAP cutoffs at 3.0 mug/L when 50<IRT<100 mug/L and 1.7 mug/L when IRT>100 were used. Positive newborns were subjected to sweat test. Optimal cutoffs were established by a non-inferiority method. RESULTS: 95 CF newborns were identified (83 classical forms (ClF), including 9 meconium ileus (MI), and 12 atypical (mild) forms (AF) Of them, IRT/DNA identified 85 (73 ClF including 5 MI and 12 AF). PAP cutoffs at 1.8 mug/L when 50< IRT<100 mug/L and 0.6 mug/L when IRT>100 mug/L would identify 82 CF: 77 ClF, including 8 MI, and 5 AF. The number of sweat tests was 314 and 1039 in the IRT/DNA and IRT/PAP strategies, respectively. CONCLUSIONS: Using the optimal cutoffs, the sensitivity of the IRT/PAP strategy would not be inferior to that of IRT/DNA if identification of MF is not required.

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158 IRT d3 Ctrl IRT PAP Cl- Mut 1 Mut 2 1 66 68 0.4 80 ƊF508del ƊF508del 2 87.8 106.5 0.5 137 E1104X E1104X 3 93.2 105.8 0.8 82 G91R ƊF508del 4 71.1 56.7 0.3 80.0 ƊF508del ƊF508del 5 67.9 54.4 1.5 99.0 ƊF508del ƊF508del 6 87.1 82.9 4.5 70.0 E1104X D110H 7 61.5 62 5.0 88.0 R553X A455E 8 62.4 63.0 14.6 110.0 2183AANG 907delCins11 9 117.0 81.5 15.6 130.0 S466X S466X Lines 1-3: false negatives in the IRT/PAP strategy, 6-9: false negatives in the IRT/DNA strategy, due to mutations not detected by the Elucigeneࡊ CF30, 45: false negatives in both strategies. Login to comment

[hide] Impact of heterozygote CFTR mutations in COPD pati... Respir Res. 2014 Feb 11;15:18. doi: 10.1186/1465-9921-15-18. Raju SV, Tate JH, Peacock SK, Fang P, Oster RA, Dransfield MT, Rowe SM
Impact of heterozygote CFTR mutations in COPD patients with chronic bronchitis.
Respir Res. 2014 Feb 11;15:18. doi: 10.1186/1465-9921-15-18., [PMID:24517344]

Abstract [show]
BACKGROUND: Cigarette smoking causes Chronic Obstructive Pulmonary Disease (COPD), the 3rd leading cause of death in the U.S. CFTR ion transport dysfunction has been implicated in COPD pathogenesis, and is associated with chronic bronchitis. However, susceptibility to smoke induced lung injury is variable and the underlying genetic contributors remain unclear. We hypothesized that presence of CFTR mutation heterozygosity may alter susceptibility to cigarette smoke induced CFTR dysfunction. Consequently, COPD patients with chronic bronchitis may have a higher rate of CFTR mutations compared to the general population. METHODS: Primary human bronchial epithelial cells derived from F508del CFTR heterozygotes and mice with (CFTR+/-) and without (CFTR+/+) CFTR heterozygosity were exposed to whole cigarette smoke (WCS); CFTR-dependent ion transport was assessed by Ussing chamber electrophysiology and nasal potential difference measurements, respectively. Caucasians with COPD and chronic bronchitis, age 40 to 80 with FEV1/FVC < 0.70 and FEV1 < 60% predicted, were selected for genetic analysis from participants in the NIH COPD Clinical Research Network's Azithromycin for Prevention of Exacerbations of COPD in comparison to 32,900 Caucasian women who underwent prenatal genetic testing. Genetic analysis involved an allele-specific genotyping of 89 CFTR mutations. RESULTS: Exposure to WCS caused a pronounced reduction in CFTR activity in both CFTR (+/+) cells and F508del CFTR (+/-) cells; however, neither the degree of decrement (44.7% wild-type vs. 53.5% F508del heterozygous, P = NS) nor the residual CFTR activity were altered by CFTR heterozygosity. Similarly, WCS caused a marked reduction in CFTR activity measured by NPD in both wild type and CFTR heterozygous mice, but the severity of decrement (91.1% wild type vs. 47.7% CF heterozygous, P = NS) and the residual activity were not significantly affected by CFTR genetic status. Five of 127 (3.9%) COPD patients with chronic bronchitis were heterozygous for CFTR mutations which was not significantly different from controls (4.5%) (P = NS). CONCLUSIONS: The magnitude of WCS induced reductions in CFTR activity was not affected by the presence of CFTR mutation heterozygosity. CFTR mutations do not increase the risk of COPD with chronic bronchitis. CFTR dysfunction due to smoking is primarily an acquired phenomenon and is not affected by the presence of congenital CFTR mutations.

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81 As expected based on genotype-phenotype correlations in the disease [33], HBE cells derived from a F508del CFTR heterozygote had slightly lower CFTR activity at baseline than wild type monolayers as measured by Table 1 List of CFTR mutations analyzed F508del R117H 1717-1G > A R117C G85E R334W 1898 + 1G > A Y122X A455E R347P 2184delA G178R I507del R553X 2789 + 5G > A G314E G542X R560T 3120 + 1G > A G330X G551D W1282X 3659delC R347H N1303K 621 + 1G > T K710X 406-1G > A R1162X 711 + 1G > T E60X G480C R1066C W1089X V520F A559T S1196X Q1238X S1251N S1255X 663delT 935delA 1161delC 1288insTA 2184insA 2307insA 2711delT 2869insG R709X R764X R1158X 574delA Q493X 1898 + 5G > T 3905insT I506T 3849 + 10kbC > T 712-1G > T Q98R Q552X S549N 1078delT H199Y 444delA S549R (T > G) 2143delT P205S 2043delG 1811 + 1.6kbA > G 3272-26A > G L206W 3791delC Y1092X (C > G) 3199del6 F508C 2108delA Y1092X (C > A) D1152H V520I 3667del4 394delTT 3876delA M1101K 1677delTA W1098X (TGA) 1812-1G > A 4016insT 1609delCA 3171delC response to forskolin stimulation (49.3 &#b1; 11.5 bc;A/cm2 in CFTR (+/+) vs. 40.5 &#b1; 5.3 bc;A/cm2 in CFTR (+/-), although this was not statistically significant (Figure 1A,B). Login to comment

[hide] A new era in the treatment of cystic fibrosis. Clin Med (Lond). 2014 Feb;14(1):76-8. doi: 10.7861/clinmedicine.14-1-76. Lane MA, Doe SJ
A new era in the treatment of cystic fibrosis.
Clin Med (Lond). 2014 Feb;14(1):76-8. doi: 10.7861/clinmedicine.14-1-76., [PMID:24532752]

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12 > Class V defects (eg A455E) result in overall reduced synthesis of normal CFTR. Login to comment

[hide] Cystic fibrosis: toward personalized therapies. Int J Biochem Cell Biol. 2014 Jul;52:192-200. doi: 10.1016/j.biocel.2014.02.008. Epub 2014 Feb 20. Ikpa PT, Bijvelds MJ, de Jonge HR
Cystic fibrosis: toward personalized therapies.
Int J Biochem Cell Biol. 2014 Jul;52:192-200. doi: 10.1016/j.biocel.2014.02.008. Epub 2014 Feb 20., [PMID:24561283]

Abstract [show]
Cystic fibrosis (CF), the most common, life-threatening monogenetic disease in Caucasians, is caused by mutations in the CFTR gene, encoding a cAMP- and cGMP-regulated epithelial chloride channel. Symptomatic therapies treating end-organ manifestations have increased the life expectancy of CF patients toward a mean of 40 years. The recent development of CFTR-targeted drugs that emerged from high-throughput screening and are capable of correcting the basic defect promises to transform the therapeutic landscape from a trial-and-error prescription to personalized medicine. This stratified approach is tailored to a specific functional class of mutations in CFTR, but can be refined further to an individual level by exploiting recent advances in ex vivo drug testing methods. These tests range from CFTR functional measurements in rectal biopsies donated by a CF patient to the use of patient-derived intestinal or pulmonary organoids. Such organoids may serve as an inexhaustible source of epithelial cells that can be stored in biobanks and allow medium- to high-throughput screening of CFTR activators, correctors and potentiators on the basis of a simple microscopic assay monitoring organoid swelling. Thus the recent breakthrough in stem cell biology allowing the culturing of mini-organs from individual patients is not only relevant for future stem cell therapy, but may also allow the preclinical testing of new drugs or combinations that are optimally suited for an individual patient.

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1687 Normalized non-corrected FIS rates differed greatly between different CFTR genotypes (non-CF > class V (A455E) > class II (F508del) > class I), and, perhaps less evident, between individuals carrying the same alleles (i.e. F508del/F508del). Login to comment

[hide] CFTR mutations spectrum and the efficiency of mole... PLoS One. 2014 Feb 26;9(2):e89094. doi: 10.1371/journal.pone.0089094. eCollection 2014. Zietkiewicz E, Rutkiewicz E, Pogorzelski A, Klimek B, Voelkel K, Witt M
CFTR mutations spectrum and the efficiency of molecular diagnostics in Polish cystic fibrosis patients.
PLoS One. 2014 Feb 26;9(2):e89094. doi: 10.1371/journal.pone.0089094. eCollection 2014., [PMID:24586523]

Abstract [show]
Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane regulator gene (CFTR). In light of the strong allelic heterogeneity and regional specificity of the mutation spectrum, the strategy of molecular diagnostics and counseling in CF requires genetic tests to reflect the frequency profile characteristic for a given population. The goal of the study was to provide an updated comprehensive estimation of the distribution of CFTR mutations in Polish CF patients and to assess the effectiveness of INNOLiPA_CFTR tests in Polish population. The analyzed cohort consisted of 738 patients with the clinically confirmed CF diagnosis, prescreened for molecular defects using INNOLiPA_CFTR panels from Innogenetics. A combined efficiency of INNOLiPA CFTR_19 and CFTR_17_TnUpdate tests was 75.5%; both mutations were detected in 68.2%, and one mutation in 14.8% of the affected individuals. The group composed of all the patients with only one or with no mutation detected (109 and 126 individuals, respectively) was analyzed further using a mutation screening approach, i.e. SSCP/HD (single strand conformational polymorphism/heteroduplex) analysis of PCR products followed by sequencing of the coding sequence. As a result, 53 more mutations were found in 97 patients. The overall efficiency of the CF allele detection was 82.5% (7.0% increase compared to INNOLiPA tests alone). The distribution of the most frequent mutations in Poland was assessed. Most of the mutations repetitively found in Polish patients had been previously described in other European populations. The most frequent mutated allele, F508del, represented 54.5% of Polish CF chromosomes. Another eight mutations had frequencies over 1%, 24 had frequencies between 1 and 0.1%; c.2052-2053insA and c.3468+2_3468+3insT were the most frequent non-INNOLiPA mutations. Mutation distribution described herein is also relevant to the Polish diaspora. Our study also demonstrates that the reported efficiency of mutation detection strongly depends on the diagnostic experience of referring health centers.

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71 Exon / intron (legacy) Exon / intron (Ensembl) Protein change SVM value cDNA (HGVS nomenclature) gDNA (cDNA +132 bp) Number of PL CF chromosomes Reference a Mutations in trans Pathogenic mutations 1 1 L15Ffs10X c.43delC 175delC 1 CFMDB 1717-1G.A 2 2 G27V 21.92 c.80G.T 212G.T 1 Novel F508del 2 2 S18RfsX16 c.54-5940_273 +10250del21kb exon2,3del21kb 66 IL19 various CF mutations i2 i2 IVS2_Donor c.164+1G.A 296+1G.A 3 CFMDB various CF mutations 3 3 G85E 22.61 c.254G.A 386G.A 1 IL17 unknown 3 3 E60X c.178G.T 310G.T 0 IL17 x 3 3 L88IfsX22 c.262_263delTT 394delTT 0 IL17 x 4 4 E92K 21.92 c.274G.A 406G.A 2 CFMDB c.164+1G.A; c.2051- 2AA.G 4 4 L101X c.302T.G 434T.G 1 CFMDB c.3717+12191C.T 4 4 K114IfsX5 c.341_353del13bp 473del13bp 1 Novel F508del 4 4 R117H 20.35 c.350G.A 482G.A 5 IL17 F508del; 2x unknown 4 4 R117C 22.07 c.349C.T 481C.T 2 CFMDB S1206X;1x unknown 4 4 L137_L138insT c.412_413insACT L138ins 1 CFMDB F508del 4 4 R153I 22.61 c.458G.T 590G.T 2 Novel F508del; c.3527delC i4 i4 IVS4_Donor c.489+1G.T 621+1G.T 5 IL17 F508del; c.489+1G.T 5 5 L165X c.494T.A 626T.A 1 Novel F508del i5 i5 IVS5_Donor c.579+1G.T 711+1G.T 0 IL19 x i5 i5 IVS5_Donor c.579+3A.G 711+3A.G 2 CFMDB 2,3del21kb; c.2052-3insA i5 i5 IVS5_Donor c.579+5G.A 711+5G.A 0 IL17 x 7 8 F311L 20.90 c.933C.G 965C.G 2 CFMDB 2x F508 7 8 G314R 20.58 c.940G.A 1072G.A 4 CFMDB various CF mutations 7 8 F316LfsX12 c.948delT 1078delT 1 IL17 unkown 7 8 R334W 22.41 c.1000C.T 1132C.T 6 IL17 various CF mutations 7 8 I336K 22.07 c.1007T.A 1139T.A 2 CFMDB 2,3de21kb; F508del 7 8 R347P 22.27 c.1040G.C 1172G.C 11 IL17 various CF mutations i7 i8 IVS8_Donor c.1116+2T.A 1248+2T.A 1 Novel Q1412X 9 10 A455E 22.61 c.1364C.A 1496C.A 0 IL17 x i9 i10 IVS10_Donor c.1392+1G.A 1524+1G.A 1 CFMDB c.3816-7delGT 10 11 S466X c.1397C.G 1529C.G 1 CFMDB G542X 10 11 I507del c.1519_1521delATC 1651delATC 2 IL19 F508del 10 11 F508del c.1521_1523delCTT 1654delCTT 805 IL19 various CF mutations i10 i11 IVS11_Acceptor c.1585-1G.A 1717-1G.A 27 IL19 various CF mutations 11 12 G542X c.1624G.T 1756G.T 25 IL19 various CF mutations 11 12 G551D 21.24 c.1624G.T 1756G.T 5 IL19 various CF mutations 11 12 Q552X c.1654C.T 1786C.T 0 IL19 x 11 12 R553X c.1657C.T 1789C.T 14 IL19 various CF mutations 11 12 R560T 21.92 c.1679G.C 1811G.C 0 IL19 x i12 i13 IVS13_Donor c.1766+1G.A 1898+1G.A 6 IL19 various CF mutations i12 i13 IVS13_Donor c.1766+1G.C 1898+1G.C 1 CFMDB F508del 13 14 H620P 21.73 c.1859A.C 1991A.C 1 CFMDB F508del 13 14 R668C//G576A 21.61//1.73 c.2002C.T//c.1727G.C 2134C.T// 1859G.C 5 b CFMDB// rs1800098 c.1585-1G.A; 4 unknown 13 14 L671X c.2012delT 2143delT 27 IL17 various CF mutations 13 14 K684SfsX38 c.2051_2052delAAinsG 2183AA.G 10 IL17 various CF mutations 13 14 K684NfsX38 c.2052delA 2184delA 0 IL17 x 13 14 Q685TfsX4 c.2052_2053insA 2184insA 15 CFMDB various CF mutationsc , 1 unknown Table 2. Cont. Exon / intron (legacy) Exon / intron (Ensembl) Protein change SVM value cDNA (HGVS nomenclature) gDNA (cDNA +132 bp) Number of PL CF chromosomes Reference a Mutations in trans 13 14 L732X c.2195T.G 2327T.G 1 CFMDB F508del 14A 15 R851X c.2551C.T 2683C.T 3 CFMDB various CF mutations 14A 15 I864SfsX28 c.2589_2599del11bp 2721del11bp 2 CFMDB F508del; 2,3del21kb i14B i16 IVS16_Donor c.2657+2_2657+3insA 2789+2insA 1 CFMDB F508del i14B i16 IVS16_Donor c.2657+5G.A 2789+5G.A 0 IL17 unkown 15 17 Y919C 21.02 c.2756A.G 2888A.G 1 CFMDB unknown 15 17 H939HfsX27 c.2817_2820delTACTC 2949delTACTC 1 Novel unkown i15 i17 IVS17_Donor c.2908+3A.C 3040+3A.C 1 Novel F508del i16 i18 IVS18_Donor c.2988+1G.A 3120+1G.A 0 IL19 x 17A 19 I1023_V1024del c.3067_3072delATAGTG 3199del6 0 IL19 x i17A i19 IVS19 c.3140-26A.G 3272-26A.G 9 IL19 various CF mutations 17B 20 L1065R 21.90 c.3194T.G 3326T.G 1 CFMDB F508del 17B 20 Y1092X c.3276C.A 3408C.A 1 CFMDB R334W i18 i21 IVS21_Donor c.3468+2_3468+3insT 3600+2insT 11 CFMDB various CF mutationsd , 1 unknown 18 21 E1126EfsX7 c.3376_3379delGAAG 3508delGAAG 1 Novel F508del 19 22 R1158X c.3472C.T 3604C.T 2 CFMDB F508del; R553X 19 22 R1162X c.3484C.T 3616C.T 1 IL17 F508del 19 22 L1177SfsX15 c.3528delC 3659delC 4 IL17 various CF mutations 19 22 S1206X c.3617C.A 3749C.A 1 CFMDB R117C i19 i22 IVS22 c.3717+12191C.T 3849+10kbC.T 58 IL17 various CF mutations 20 23 G1244R 22.62 c.3730G.C 3862G.C 1 CFMDB F508del 20 23 S1251N 22.28 c.3752G.A 3884G.A 0 IL19 x 20 23 L1258FfsX7 c.3773_3774insT 3905insT 0 IL19 x 20 23 V1272VfsX28 c.3816_3817delGT 3944delGT 1 CFMDB c.1392+1G.A 20 23 W1282X c.3846G.A 3978G.A 9 IL19 various CF mutations 21 24 N1303K 22.62 c.3909C.G 4041C.G 18 IL19 various CF mutations 22 25 V1327X c.3979delG 4111delG 1 Novel F508del 22 25 S1347PfsX13 c.4035_4038dupCCTA c.4167dupCCTA 1 CFMDB 2,3del21kb 23 26 Q1382X c.4144C.T 4276C.T 1 CFMDB F508del 23 26 Q1412X c.4234C.T 4366C.T 2 CFMDB F508del; c.1116+2T.A i23 i26 IVS26_Donor c.4242+1G.T 4374+1G.T 1 CFMDB F508del Sequence changes of uncertain pathogenic effect, tentatively counted as mutations 6A 6 E217G 0.30 c.650A.G 782A.G 1 CFMDB; rs1219109046 unknown 7 8 R352Q 20.01 c.1055G.A 1187G.A 1 CFMDB; rs121908753 F508del 7 8 Q359R 0.33 c.1076A.G 1208A.G 1 CFMDB F508del i8 i9 IVS9 c.1210-12T5_1210- 34_35 (TG)12 1332-12Tn_- 34TGm 6 CFMDB F508del; 3x unknown i8 i9 IVS9 c.1210-12T5_1210- 34_35 (TG)13 1332-12Tn_- 34TGm 2 CFMDB 2143delT; 1x unknown i8 i9 IVS9 c.1210-12T8 1332-12Tn 1 Novel unknown 10 11 I506V 20.21 c.1516A.G 1648A.G 1 CFMDB; rs1800091 unknown 12 13 V562L 0.79 c.1684G.C 1816G.C 1 CFMDB; rs1800097 unknown 13 14 G723V 0.44 c.2168G.T 2300G.T 1 CFMDB; rs200531709 unknown 15 17 D924N 0.03 c.2770G.A 2902G.A 1 CFMDB; rs201759207 unknown patient with F508del on another allele) was not supported by the SVM value (+0.35); the patient was PS and had ambiguous chloride values (45, 64 and 83 mmol/L). 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103 IL17 (INNOLiPA_CFTR17_TnUpdate): 621+1G.T; 3849+10kbC.T; 2183AA.G; 394delTT; 2789+5G.A; R1162X; 3659delC; R117H; R334W; R347P; G85E; 1078delT; A455E; 2143delT; E60X; 2184delA; 711+5G.A; polymorphism 5T/7T/9T. Login to comment

[hide] Genetics of cystic fibrosis: CFTR mutation classif... Int J Biochem Cell Biol. 2014 Jul;52:94-102. doi: 10.1016/j.biocel.2014.02.023. Epub 2014 Mar 12. Fanen P, Wohlhuter-Haddad A, Hinzpeter A
Genetics of cystic fibrosis: CFTR mutation classifications toward genotype-based CF therapies.
Int J Biochem Cell Biol. 2014 Jul;52:94-102. doi: 10.1016/j.biocel.2014.02.023. Epub 2014 Mar 12., [PMID:24631642]

Abstract [show]
Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes an epithelial anion channel. Since the identification of the disease in 1938 and up until 2012, CF patients have been treated exclusively with medications aimed at bettering their respiratory, digestive, inflammatory and infectious symptoms. The identification of the CFTR gene in 1989 gave hopes of rapidly finding a cure for the disease, for which over 1950 mutations have been identified. Since 2012, recent approaches have enabled the identification of small molecules targeting either the CFTR protein directly or its key processing steps, giving rise to novel promising therapeutic tools. This review presents the current CFTR mutation classifications according to their clinical consequences and to their effect on the structure and function of the CFTR channel. How these classifications are essential in the establishment of mutation-targeted therapeutic strategies is then discussed. The future of CFTR-targeted treatment lies in combinatory therapies that will enable CF patients to receive a customized treatment.

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74 23 ACMG recommended panel of classic CF-causing mutations G85E R117H R334W R347P A455E I507del F508del G542X G551D R553X R560T R1162X W1282X N1303K 621 + 1G > T 711 + 1G > T 1717 - 1G > A 1898 + 1G > A 2184delA 2789 + 5G > A 3120 + 1G > A 3659delC 3849 + 10kbC > T Additional or alternative mutations present at significant frequencies in an ethnic population served by a newborn screening program may be assessed. Login to comment

[hide] Understanding how cystic fibrosis mutations disrup... Int J Biochem Cell Biol. 2014 Jul;52:47-57. doi: 10.1016/j.biocel.2014.04.001. Epub 2014 Apr 13. Wang Y, Wrennall JA, Cai Z, Li H, Sheppard DN
Understanding how cystic fibrosis mutations disrupt CFTR function: from single molecules to animal models.
Int J Biochem Cell Biol. 2014 Jul;52:47-57. doi: 10.1016/j.biocel.2014.04.001. Epub 2014 Apr 13., [PMID:24727426]

Abstract [show]
Defective epithelial ion transport is the hallmark of the life-limiting genetic disease cystic fibrosis (CF). This abnormality is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), the ATP-binding cassette transporter that functions as a ligand-gated anion channel. Since the identification of the CFTR gene, almost 2000 disease-causing mutations associated with a spectrum of clinical phenotypes have been reported, but the majority remain poorly characterised. Studies of a small number of mutations including the most common, F508del-CFTR, have identified six general mechanisms of CFTR dysfunction. Here, we review selectively progress to understand how CF mutations disrupt CFTR processing, stability and function. We explore CFTR structure and function to explain the molecular mechanisms of CFTR dysfunction and highlight new knowledge of disease pathophysiology emerging from large animal models of CF. Understanding CFTR dysfunction is crucial to the development of transformational therapies for CF patients.

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2026 This class of CF mutations includes promoter mutations that alter transcription (e.g. 125 G࢐C), nucleotide changes that promote alterative splicing of CFTR transcripts (e.g. 3849 + 10 kb C࢐T) and amino acid substitutions, which cause inefficient protein maturation (e.g. A455E) (Zielenski and Tsui, 1995). Login to comment
2028 This idea is exemplified by A455E, the first CF-PS mutation to be associated with milder lung disease (Gan et al., 1995). Login to comment
2029 When studied in heterologous cells, A455E-CFTR disrupted the processing and intracellular transport of CFTR, albeit not as severely as F508del-CFTR (Sheppard et al., 1995). Login to comment
2030 However, the conduction, permeation and gating properties of A455E-CFTR were almost indistinguishable from those of wild-type CFTR (Sheppard et al., 1995). Login to comment

[hide] New pharmacological approaches for cystic fibrosis... Pharmacol Ther. 2015 Jan;145:19-34. doi: 10.1016/j.pharmthera.2014.06.005. Epub 2014 Jun 14. Bell SC, De Boeck K, Amaral MD
New pharmacological approaches for cystic fibrosis: promises, progress, pitfalls.
Pharmacol Ther. 2015 Jan;145:19-34. doi: 10.1016/j.pharmthera.2014.06.005. Epub 2014 Jun 14., [PMID:24932877]

Abstract [show]
With the discovery of the CFTR gene in 1989, the search for therapies to improve the basic defects of cystic fibrosis (CF) commenced. Pharmacological manipulation provides the opportunity to enhance CF transmembrane conductance regulator (CFTR) protein synthesis and/or function. CFTR modulators include potentiators to improve channel gating (class III mutations), correctors to improve abnormal CFTR protein folding and trafficking (class II mutations) and stop codon mutation read-through drugs relevant for patients with premature stop codons (most class I mutations). After several successful clinical trials the potentiator, ivacaftor, is now licenced for use in adults and children (>six years), with CF bearing the class III G551D mutation and FDA licence was recently expanded to include 8 additional class III mutations. Alternative approaches for class I and class II mutations are currently being studied. Combination drug treatment with correctors and potentiators appears to be required to restore CFTR function of F508del, the most common CFTR mutation. Alternative therapies such as gene therapy and pharmacological modulation of other ion channels may be advantageous because they are mutation-class independent, however progress is less well advanced. Clinical trials for CFTR modulators have been enthusiastically embraced by patients with CF and health care providers. Whilst novel trial end-points are being evaluated allowing CFTR modulators to be efficiently tested, many challenges related to the complexity of CFTR and the biology of the epithelium still need to be overcome.

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544 Mutation Alternative name Allele frequency (% of total known) in ECFSPR 2010 Allele frequency (% of total known mutations) in 2010 ECFSPR F508del 64.5 Most frequent mutation worldwide Southeast to Northwest increasing prevalence in Europe IL 25.5 to DK 82.6 Mutations with an overall EU prevalence above 1% G542X Mediterranean mutation 2.5 GR 6.7, ES 6.0 N1303K Ancient Phoenician mutation 1.9 IT 4.2 W1282X Jewish Ashkenazi mutation 1.2 IL 22.4 G551D Celtic mutation 1.1 IE 7.3 1717-1GNA Italian mutation 1.0 IT 3.7 Mutations with an overall EU prevalence below 0.5% G85E PT 3.5 A455E Dutch mutation NL 3.5 CFTR dele 2,3 Slavic mutation CZ 5.2, BY 6.7 394delTT Nordic mutation SE 7.9, DK 2.0 3905insT Swiss mutation CH 2.4 R1162X Italian mutation IT 7.8 A561E Portuguese mutation PT 3.2 Abbreviations ECFSPR - European Cystic Fibrosis Society Patient Registry. Login to comment
547 Class Type of defect List of mutations attributed to this class Class I Defective protein production Nonsense mutations: G542X, R1162X, RW1282X Deletions and insertions: CFTRdele2,3; 1078delT; 1717-1G ࢐ A; 3659delC; 621+1G N T Class II Defective protein processing G85E, F508del, I507del, R560T, A561E, R1066C, N1303K Class III Defective protein regulation (gating) G178R, S549N, S549R, G551D, G551S, G970R, G1244E, S1251N, S1255P, G1349D Class IV Defective protein conductance R334W, R347P, R117H Class V Reduced amount of functioning protein 2789+5G ࢐ A, 3272-26ANG, 3849+10KbC ࢐ T, A455E Class VI Reduced cell surface stability Rescued F508del, c.120del23 Unclassified All other mutations, including those unknown a F508del-CFTR pocket (at NBD1:ICL4 interface) (Farinha et al., 2013). Login to comment

[hide] Novel opportunities for CFTR-targeting drug develo... Rare Dis. 2013 Nov 11;1:e27112. doi: 10.4161/rdis.27112. eCollection 2013. Dekkers JF, van der Ent CK, Beekman JM
Novel opportunities for CFTR-targeting drug development using organoids.
Rare Dis. 2013 Nov 11;1:e27112. doi: 10.4161/rdis.27112. eCollection 2013., [PMID:25003014]

Abstract [show]
Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CFTR mutations lead to production of non-functional CFTR, reduced amounts of normal functioning CFTR or misfolded CFTR with defects in trafficking or function. For decades, CF treatment has been focused on the symptoms of CF, but pharmacotherapy using small molecules that target the basic defect of CF, the mutant CFTR protein, is now possible for a limited amount of subjects with CF. This raises the exciting possibility that the majority of people with CF may receive effective treatment targeting the different CFTR mutants in the future. We recently described a functional CFTR assay using rectal biopsies from subjects with CF that were cultured in vitro into self-organizing mini-guts or organoids. We here describe how this model may assist in the discovery of new CFTR-targeting drugs, the subjects that may benefit from these drugs, and the mechanisms underlying variability in CFTR genotype-phenotype relations.

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41 FIS varied greatly between organoids derived from different CF subjects, and was largest in organoids from patients with milder CF that express CFTR-A455E.17,24 We detected FIS in all organoids expressing CFTR-F508del, also when it was expressed from just a single allele. Login to comment

[hide] Mechanisms of CFTR functional variants that impair... PLoS Genet. 2014 Jul 17;10(7):e1004376. doi: 10.1371/journal.pgen.1004376. eCollection 2014 Jul. LaRusch J, Jung J, General IJ, Lewis MD, Park HW, Brand RE, Gelrud A, Anderson MA, Banks PA, Conwell D, Lawrence C, Romagnuolo J, Baillie J, Alkaade S, Cote G, Gardner TB, Amann ST, Slivka A, Sandhu B, Aloe A, Kienholz ML, Yadav D, Barmada MM, Bahar I, Lee MG, Whitcomb DC
Mechanisms of CFTR functional variants that impair regulated bicarbonate permeation and increase risk for pancreatitis but not for cystic fibrosis.
PLoS Genet. 2014 Jul 17;10(7):e1004376. doi: 10.1371/journal.pgen.1004376. eCollection 2014 Jul., [PMID:25033378]

Abstract [show]
CFTR is a dynamically regulated anion channel. Intracellular WNK1-SPAK activation causes CFTR to change permeability and conductance characteristics from a chloride-preferring to bicarbonate-preferring channel through unknown mechanisms. Two severe CFTR mutations (CFTRsev) cause complete loss of CFTR function and result in cystic fibrosis (CF), a severe genetic disorder affecting sweat glands, nasal sinuses, lungs, pancreas, liver, intestines, and male reproductive system. We hypothesize that those CFTR mutations that disrupt the WNK1-SPAK activation mechanisms cause a selective, bicarbonate defect in channel function (CFTRBD) affecting organs that utilize CFTR for bicarbonate secretion (e.g. the pancreas, nasal sinus, vas deferens) but do not cause typical CF. To understand the structural and functional requirements of the CFTR bicarbonate-preferring channel, we (a) screened 984 well-phenotyped pancreatitis cases for candidate CFTRBD mutations from among 81 previously described CFTR variants; (b) conducted electrophysiology studies on clones of variants found in pancreatitis but not CF; (c) computationally constructed a new, complete structural model of CFTR for molecular dynamics simulation of wild-type and mutant variants; and (d) tested the newly defined CFTRBD variants for disease in non-pancreas organs utilizing CFTR for bicarbonate secretion. Nine variants (CFTR R74Q, R75Q, R117H, R170H, L967S, L997F, D1152H, S1235R, and D1270N) not associated with typical CF were associated with pancreatitis (OR 1.5, p = 0.002). Clones expressed in HEK 293T cells had normal chloride but not bicarbonate permeability and conductance with WNK1-SPAK activation. Molecular dynamics simulations suggest physical restriction of the CFTR channel and altered dynamic channel regulation. Comparing pancreatitis patients and controls, CFTRBD increased risk for rhinosinusitis (OR 2.3, p<0.005) and male infertility (OR 395, p<<0.0001). WNK1-SPAK pathway-activated increases in CFTR bicarbonate permeability are altered by CFTRBD variants through multiple mechanisms. CFTRBD variants are associated with clinically significant disorders of the pancreas, sinuses, and male reproductive system.

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269 67 SNPs (125GtoC, 1716G.A, 1717-1G.A, 1898+1G.A, 2183AA.G, 2184delA, 2789+5G.A, 3120+1G.A, 3659delC, 3849+10kbC.T, 621+ 1G.T, 711+5G.A, A455E, D110H, D1152H, D1270N, D443Y, D579G, F1052V, F1074L, F508C, F508del, G1069R, G1244E, G1349D, G178R, G542X, G551D, G551S, I1131L/V, I148T, I336K/T, I507del, I807M, IVS8T5, K1180T, L1065P, L967S, L997F, M1V, M470V, M952I, M952T, N1303K, P67L, Q1463Q, R1070Q, R1162X, R117C, R117H, R170H, R258G, R297Q, R31C, R352Q, R553X, R668C, R74W, R75Q, S1235R, S1255P, S485R, S977F, T338I, T854T, V201M, W1282X) were multiplexed into 6 wells; 14 SNPs (S492F, S945L, R74Q, R560T, R1162L, G85E, I1027T, R334W, R347P, G576A, 711+1G.T, 1001+11C.T, P1290P, 3199del6) were ascertained separately via TaqMan Gene Expression Assays, with repeat confirmation of all positive results. Login to comment

[hide] Molecular genetic testing for cystic fibrosis: lab... Genet Med. 2015 Mar;17(3):219-25. doi: 10.1038/gim.2014.93. Epub 2014 Jul 31. Lyon E, Schrijver I, Weck KE, Ferreira-Gonzalez A, Richards CS, Palomaki GE
Molecular genetic testing for cystic fibrosis: laboratory performance on the College of American Pathologists external proficiency surveys.
Genet Med. 2015 Mar;17(3):219-25. doi: 10.1038/gim.2014.93. Epub 2014 Jul 31., [PMID:25077647]

Abstract [show]
BACKGROUND: Molecular testing for cystic fibrosis mutations is widespread and routine in reproductive decision making and diagnosis. Our objective was to assess the level of performance of laboratories for this test. METHODS: The College of American Pathologists administers external proficiency testing with multiple DNA samples distributed biannually. RESULTS are analyzed, reviewed, and graded by the joint College of American Pathologists/American College of Medical Genetics and Genomics Biochemical and Molecular Genetics Committee. Assessment is based on genotype and associated clinical interpretation. RESULTS: Overall, 357 clinical laboratories participated in the proficiency testing survey between 2003 and 2013 (322 in the United States and 35 international). In 2013, US participants reported performing nearly 120,000 tests monthly. Analytical sensitivity and specificity of US laboratories were 98.8% (95% confidence interval: 98.4-99.1%) and 99.6% (95% confidence interval: 99.4-99.7%), respectively. Analytical sensitivity improved between 2003 and 2008 (from 97.9 to 99.3%; P = 0.007) and remained steady thereafter. Clinical interpretation matched the intended response for 98.8, 86.0, and 91.0% of challenges with no, one, or two mutations, respectively. International laboratories performed similarly. DISCUSSION: Laboratory testing for cystic fibrosis in the United States has improved since 2003, and these data demonstrate a high level of quality. Neither the number of samples tested nor test methodology affected performance.

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106 The lowest analytical sensitivity (91.1%) for a single challenge was recorded for a 2003 compound heterozygous sample (621+1G>T/A455E). Login to comment
118 90 95 A (621 + 1G>T/A455E) (G542X/G542X) (I507 wild type or negative?) Login to comment

[hide] Comprehensive CFTR gene analysis of the French cys... Genet Med. 2015 Feb;17(2):108-16. doi: 10.1038/gim.2014.113. Epub 2014 Aug 14. Audrezet MP, Munck A, Scotet V, Claustres M, Roussey M, Delmas D, Ferec C, Desgeorges M
Comprehensive CFTR gene analysis of the French cystic fibrosis screened newborn cohort: implications for diagnosis, genetic counseling, and mutation-specific therapy.
Genet Med. 2015 Feb;17(2):108-16. doi: 10.1038/gim.2014.113. Epub 2014 Aug 14., [PMID:25122143]

Abstract [show]
PURPOSE: Newborn screening (NBS) for cystic fibrosis (CF) was implemented throughout France in 2002. It involves a four-tiered procedure: immunoreactive trypsin (IRT)/DNA/IRT/sweat test [corrected] was implemented throughout France in 2002. The aim of this study was to assess the performance of molecular CFTR gene analysis from the French NBS cohort, to evaluate CF incidence, mutation detection rate, and allelic heterogeneity. METHODS: During the 8-year period, 5,947,148 newborns were screened for cystic fibrosis. The data were collected by the Association Francaise pour le Depistage et la Prevention des Handicaps de l'Enfant. The mutations identified were classified into four groups based on their potential for causing disease, and a diagnostic algorithm was proposed. RESULTS: Combining the genetic and sweat test results, 1,160 neonates were diagnosed as having cystic fibrosis. The corresponding incidence, including both the meconium ileus (MI) and false-negative cases, was calculated at 1 in 4,726 live births. The CF30 kit, completed with a comprehensive CFTR gene analysis, provides an excellent detection rate of 99.77% for the mutated alleles, enabling the identification of a complete genotype in 99.55% of affected neonates. With more than 200 different mutations characterized, we confirmed the French allelic heterogeneity. CONCLUSION: The very good sensitivity, specificity, and positive predictive value obtained suggest that the four-tiered IRT/DNA/IRT/sweat test procedure may provide an effective strategy for newborn screening for cystic fibrosis.

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53 Because only a limited number of functional studies have assessed the pathogenicity of variants, mutations have been classified in previous studies according to their disease-causing potential.16,22,23 Based on the recommendations and data from these studies (UMD-CFTR-France),24 variants were classified into four groups: A, CF-causing; B, associated with CFTR-RDs; C, no clinical consequences; and D, unknown or Table 1ߒ Allelic frequencies of CF30-kit mutations, identified in neonates with CF, and correspondence between traditional mutation nomenclature and that on the Human Genome Variation Society website Frequency (F) % Mutation Legacy mutation nomenclature Number of alleles/2,320 % of alleles/2,320 Cumulative % ࣙ5 p.Phe508del F508del 1,560 67.24 67.24 p.Gly542* G542X 113 3.19 10.51 p.Asn1303Lys N1303K 81 1.98 c.1585-1G>A 1717-1G>A 48 1.47 1.00ࣙFࣙ4.99 c.2657ߙ+ߙ5G>A 2789ߙ+ߙ5G>A 37 1.42 p.Arg553* R553X 36 1.29 p.Gly551Asp G551D 31 1.16 p.Tyr122* Y122X 26 0.97 6.86 c.2988ߙ+ߙ1G>A 3120ߙ+ߙ1G>A 22 0.82 c.579ߙ+ߙ1G>T 711ߙ+ߙ1G>T 18 0.67 p.Ile507del I507del 17 0.63 c.3140-26A>G 3272-26A>G 16 0.59 0.40ࣙFࣙ0.99 p.Arg347Pro R347P 15 0.56 p.Arg1162* R1162X 15 0.56 p.Trp1282* W1282X 14 0.52 p.Tyr1092* Y1092X 13 0.48 c.2051_2052delinsG 2183AA>G 12 0.45 c.3528delC 3659delC 11 0.41 c.1680-886A>G 1811ߙ+ߙ1.6kbA>G 9 0.39 p.Gly85Glu G85E 8 0.34 3.06 p.Ser1251Asn S1251N 7 0.30 p.Arg334Trp R334W 7 0.30 p.Arg117His R117H 7 0.30 0.1ࣙFࣙ0.39 p.Trp846* W846X 6 0.26 c.489ߙ+ߙ1G>T 621ߙ+ߙ1G>T 6 0.26 c.948delT 1078delT 5 0.22 p.Ala455Glu A455E 5 0.22 p.Glu60* E60X 4 0.17 c.262_263delTT 394delTT 4 0.17 c.3718-2477C>T 3849ߙ+ߙ10kbC>T 3 0.13 Total 2,034 87.67 87.67 Mutations are clustered into four groups of frequency intervals (>5%, 1-4.99%, 0.99-0.4%, and <0.4%). Login to comment

[hide] Full-open and closed CFTR channels, with lateral t... Cell Mol Life Sci. 2015 Apr;72(7):1377-403. doi: 10.1007/s00018-014-1749-2. Epub 2014 Oct 7. Mornon JP, Hoffmann B, Jonic S, Lehn P, Callebaut I
Full-open and closed CFTR channels, with lateral tunnels from the cytoplasm and an alternative position of the F508 region, as revealed by molecular dynamics.
Cell Mol Life Sci. 2015 Apr;72(7):1377-403. doi: 10.1007/s00018-014-1749-2. Epub 2014 Oct 7., [PMID:25287046]

Abstract [show]
In absence of experimental 3D structures, several homology models, based on ABC exporter 3D structures, have provided significant insights into the molecular mechanisms underlying the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, a chloride channel whose defects are associated with cystic fibrosis (CF). Until now, these models, however, did not furnished much insights into the continuous way that ions could follow from the cytosol to the extracellular milieu in the open form of the channel. Here, we have built a refined model of CFTR, based on the outward-facing Sav1866 experimental 3D structure and integrating the evolutionary and structural information available today. Molecular dynamics simulations revealed significant conformational changes, resulting in a full-open channel, accessible from the cytosol through lateral tunnels displayed in the long intracellular loops (ICLs). At the same time, the region of nucleotide-binding domain 1 in contact with one of the ICLs and carrying amino acid F508, the deletion of which is the most common CF-causing mutation, was found to adopt an alternative but stable position. Then, in a second step, this first stable full-open conformation evolved toward another stable state, in which only a limited displacement of the upper part of the transmembrane helices leads to a closure of the channel, in a conformation very close to that adopted by the Atm1 ABC exporter, in an inward-facing conformation. These models, supported by experimental data, provide significant new insights into the CFTR structure-function relationships and into the possible impact of CF-causing mutations.

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360 The effects of remaining mutations listed in CFTR2 database can also be well understood in light of our structural data: (1) A455E has indeed no room to be well adapted, (2) G1244E (mentioned above) also occurs in a well conserved position (position 23 in Online Resource 2), (3) L467P might disturb the helix in which it is included, (4) G1349D is in the non-canonical ATP-binding site and, alike its corresponding G551D, has no room to be well adapted in presence of ATP, and finally (5) N1303K might disturb the large Q-loop of the NBD2 a-helical subdomain (position 42 in Online Resource 1 and Online Resource 2). Login to comment

[hide] Rescue of NBD2 mutants N1303K and S1235R of CFTR b... PLoS One. 2015 Mar 23;10(3):e0119796. doi: 10.1371/journal.pone.0119796. eCollection 2015. Rapino D, Sabirzhanova I, Lopes-Pacheco M, Grover R, Guggino WB, Cebotaru L
Rescue of NBD2 mutants N1303K and S1235R of CFTR by small-molecule correctors and transcomplementation.
PLoS One. 2015 Mar 23;10(3):e0119796. doi: 10.1371/journal.pone.0119796. eCollection 2015., [PMID:25799511]

Abstract [show]
Although, the most common Cystic Fibrosis mutation, DeltaF508, in the cystic fibrosis transmembrane regulator. (CFTR), is located in nucleotide binding domain (NBD1), disease-causing mutations also occur in NBD2. To provide information on potential therapeutic strategies for mutations in NBD2, we studied, using a combination of biochemical approaches and newly created cell lines, two disease-causing NBD2 mutants, N1303K and S1235R. Surprisingly, neither was rescued by low temperature. Inhibition of proteasomes with MG132 or aggresomes with tubacin rescued the immature B and mature C bands of N1303K and S1235R, indicating that degradation occurs via proteasomes and aggresomes. We found no effect of the lysosome inhibitor E64. Thus, our results show that these NBD2 mutants are processing mutants with unique characteristics. Several known correctors developed to rescue DeltaF508-CFTR, when applied either alone or in combination, significantly increased the maturation of bands B and C of both NBD 2 mutants. The best correction occurred with the combinations of C4 plus C18 or C3 plus C4. Co-transfection of truncated CFTR (27-264) into stably transfected cells was also able to rescue them. This demonstrates for the first time that transcomplementation with a truncated version of CFTR can rescue NBD2 mutants. Our results show that the N1303K mutation has a more profound effect on NBD2 processing than S1235R and that small-molecule correctors increase the maturation of bands B and C in NBD2 mutants. In addition, 27-264 was able to transcomplement both NDB2 mutants. We conclude that differences and similarities occur in the impact of mutations on NBD2 when compared to DeltaF508-CFTR suggesting that individualized strategies may be needed to restore their function. Finally our results are important because they suggest that gene or corrector molecule therapies either alone or in combination individualized for NBD2 mutants may be beneficial for patients bearing N1303K or S1235R mutations.

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38 We have recently shown that another NBD1 mutant, A455E, can be rescued [12]. Login to comment
209 Transcomplementation by Ɗ27-264 is able to rescue NBD2 mutants We have previously shown that truncated forms of CFTR such as Ɗ264 and Ɗ27-264-CFTR can rescue the NBD1 mutants ƊF508-CFTR and A455E CFTR [27,42], but it was still not clear whether the NBD2 mutants could also be transcomplemented. Login to comment
244 Unlike ƊF508-CFTR and A455E, both of which undergo significant trafficking of immature band B to mature band C [12], the mature bands of N1303K and S1235R are not enhanced when cells are grown at low temperature. Login to comment
251 This response of S1235R is in sharp contrast to that of A455E, which is not sensitive to tubacin. Login to comment
259 These results point to differences in the processing of these NBD2 mutants when compared to two of the mutations in NBD1, A455E and ƊF508-CFTR. Login to comment
322 2012; 67: 12-18. doi: 10.1136/thoraxjnl-2011-200393 PMID: 21825083 12. Cebotaru L, Rapino D, Cebotaru V, Guggino WB Correcting the cystic fibrosis disease mutant, A455E CFTR. Login to comment

[hide] Clinical diagnostic Next-Generation sequencing: th... Scand J Clin Lab Invest. 2015 Sep;75(5):374-81. doi: 10.3109/00365513.2015.1031689. Epub 2015 Apr 15. Loukas YL, Thodi G, Molou E, Georgiou V, Dotsikas Y, Schulpis KH
Clinical diagnostic Next-Generation sequencing: the case of CFTR carrier screening.
Scand J Clin Lab Invest. 2015 Sep;75(5):374-81. doi: 10.3109/00365513.2015.1031689. Epub 2015 Apr 15., [PMID:25874479]

Abstract [show]
A 23-mutation panel for CFTR carrier screening is recommended to women of reproductive age by the American College of Obstetricians and Gynecologists. In the present study the optimized efficiency regarding the carrier rate of Next-Generation sequencing (NGS) technology is compared to the one of limited mutation detection panels. A total of 824 consequent cases were subjected to the commercial Cystic Fibrosis Genotyping Assay. Some 188 negative samples randomly selected from the initial group of probands were further subjected to an extended mutation panel characterized by 92% detection rate, as well as to massive parallel sequencing. Twenty-two probands subjected to the commercial assay proved to carry one mutation included in the ACOG panel (carrier rate 0.0267). The latter panels revealed the presence of mutations not included in the ACOG panel in four probands, resulting to an increase of carrier rate of 0.0106 in the case of in-house panel and an increase of rate of 0.0213 if NGS was used. The above data seem to support the implementation of NGS in the routine CFTR carrier screening.

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36 Sample code Source Genotype NA18668*2 Coriell Cell Repositories* CFTR, CFdelex2,3/p.F508del NA07830 Coriell Cell Repositories* CFTR, F508del/556delA NA11275 Coriell Cell Repositories* CFTR, 3659delC/F508del NA11277 Coriell Cell Repositories* CFTR, I507del/wt NA11860 Coriell Cell Repositories* CFTR, 3849af9;10kb,Cb0e;T/3849af9;10kb,Cb0e;T 40C2 CDC** CFTR, F508del/R334W 10C4 CDC** CFTR, 2184delA/394delTT CDC2 CDC** CFTR, F508del/Exon 17&#aa;-17b-18del 212C4 CDC** CFTR, F508del/3659delC 412C2 CDC** CFTR, F508del/R334W 213C4 CDC** CFTR, W1282X/W1282X 21C2 CDC** CFTR, 1717-1Gb0e;A/1154insTC 412C5 CDC** CFTR, F508del/2183AAb0e;G 412C1 CDC** CFTR, 2184delA/394delTT 212C5 CDC** CFTR, F508del/3849af9;10KbCb0e;T 38C4 CDC** CFTR, R553X/wt 48C1 CDC** CFTR, F508del/G542X 48C3 CDC** CFTR, F508del/G551D 19C4 CDC** CFTR, F508del/R560T 19C5 CDC** CFTR, G551D/G551D 29C3 CDC** CFTR, 621af9;1Gb0e;T/N1303K 29C5 CDC** CFTR, F508del/2789af9;5Gb0e;A 49C1 CDC** CFTR, 3120af9;1Gb0e;A/L467P# 49C3 CDC** CFTR, 621af9;1Gb0e;T/R1162X 40C5 CDC** CFTR, 711af9;1Gb0e;T/wt 21C1 CDC** CFTR, A455E/F508del 112C2 CDC** CFTR, 1898af9;1Gb0e;A/F508del 214C5 CDC** CFTR, F508del/3140-26Ab0e;G *http://ccr.coriell.org/; **CDC, Center for Disease Control & Prevention, http://www.cdc.gov/; #According to CDC report, its clinical significance is unknown. Login to comment
94 Mutation cDNA Coverage Score Reference allele (F/R strand) Mutant allele (F/R strand) Genotype F508del* c.1521_1523delCTT 2080 26.5 491/557 523/504 HET 556delA c.424delA 2168 26.7 524/557 547/536 HET 3659delC* c.3528delC 2359 27.0 573/605 566/609 HET I507del c.1519_1521delATC 2246 26.8 508/612 619/501 HET 3849af9;10kb,Cb0e;T c.3717af9;12191Cb0e;T 3596 28.4 - 1834/1756 HOM 3849af9;10kb,Cb0e;T c.3717af9;12191Cb0e;T 4169 29.0 1023/1059 1116/967 HET R334W* c.1000Cb0e;T 2473 27.1 636/599 626/609 HET 2184delA* c.2052delA 3069 27.9 734/801 792/738 HET 394delTT* c.262_263delTT 3176 28.0 775/811 819/766 HET W1282X c.3846Gb0e;A 4268 29.0 - 2168/2096 HOM 1717-1Gb0e;A c.1585-1Gb0e;A 3863 28.7 922/1007 985/944 HET 1154insTC c.1022_1023insTC 4021 28.8 1058/1039 979/941 HET 2183AAb0e;G c.2051_2052delAAinsG 3927 28.8 1023/996 974/926 HET R553X c.1657Cb0e;T 6027 30.2 1532/1480 1476/1534 HET G542X c.1624Gb0e;T 3862 28.7 933/996 925/1002 HET G551D c.1652Gb0e;A 5225 29.7 1257/1351 1341/1268 HET G551D c.1652Gb0e;A 4862 29.5 - 2487/2369 HOM R560T c.1679Gb0e;C 3542 28.4 861/908 915/853 HET 621af9;1Gb0e;T* c.489af9;1Gb0e;T 2256 26.8 534/592 606/519 HET N1303K c.3909Cb0e;G 2126 26.6 534/528 492/568 HET 2789af9;5Gb0e;A c.2657af9;5Gb0e;A 3453 28.3 824/901 895/828 HET 3120af9;1Gb0e;A c.2988af9;1Gb0e;A 3021 27.8 721/787 802/707 HET L467P c.1400Cb0e;T 3848 28.7 928/993 1003/920 HET R1162X c.3484Cb0e;T 4180 29.0 1021/1065 1112/976 HET 711af9;1Gb0e;T c.579af9;1Gb0e;T 4222 29.0 1036/1072 1001/1108 HET A455E c.1364Cb0e;A 5621 30.0 1365/1443 1438/1370 HET 1898af9;1Gb0e;A c.1766af9;1Gb0e;A 2934 27.7 683/782 702/762 HET 3272-26Ab0e;G 3140-26Ab0e;G 3755 28.6 902/973 1008/867 HET of the majority of CFTR mutations carriers in our region. Login to comment

[hide] Deleterious impact of hyperglycemia on cystic fibr... J Cyst Fibros. 2015 Apr 24. pii: S1569-1993(15)00102-2. doi: 10.1016/j.jcf.2015.04.002. Bilodeau C, Bardou O, Maille E, Berthiaume Y, Brochiero E
Deleterious impact of hyperglycemia on cystic fibrosis airway ion transport and epithelial repair.
J Cyst Fibros. 2015 Apr 24. pii: S1569-1993(15)00102-2. doi: 10.1016/j.jcf.2015.04.002., [PMID:25920899]

Abstract [show]
BACKGROUND: Cystic fibrosis (CF)-related diabetes (CFRD) is associated with faster pulmonary function decline. Thus, we evaluated the impact of hyperglycemia on airway epithelial repair and transepithelial ion transport, which are critical in maintaining lung integrity and function. METHODS: Non-CF and CF airway epithelial cells were exposed to low (LG) or high (HG) glucose before ion current and wound repair rate measurements. RESULTS: CFTR and K+ currents decreased after HG treatments. HG also reduced the wound healing rates of non-CF and CF cell monolayers. Although CFTR correction with VRT-325 accelerated the healing rates of CF cells monolayers under LG conditions, this improvement was significantly abrogated under HG conditions. CONCLUSIONS: Our data highlights a deleterious impact of hyperglycemia on ion transport and epithelial repair functions, which could contribute to the deterioration in lung function in CFRD patients. HG may also interfere with the beneficial effects of CFTR rescue on airway epithelial repair.

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46 Primary human airway nasal cells were recovered after polypectomy procedures from CF patients with various genotypes (four homozygous ƊF508/ƊF508, two ƊF508/N1303, one ƊF508/undefined and one ƊF508/A455E, median age 21.5 yrs, mean FEV1 of 83.1 &#b1; 6.1%), according to protocols approved by the CHUM ethical committee and with written informed consent by the patients. Login to comment

[hide] Translating the genetics of cystic fibrosis to per... Transl Res. 2015 Apr 15. pii: S1931-5244(15)00131-0. doi: 10.1016/j.trsl.2015.04.008. Corvol H, Thompson KE, Tabary O, le Rouzic P, Guillot L
Translating the genetics of cystic fibrosis to personalized medicine.
Transl Res. 2015 Apr 15. pii: S1931-5244(15)00131-0. doi: 10.1016/j.trsl.2015.04.008., [PMID:25940043]

Abstract [show]
Cystic fibrosis (CF) is the most common life-threatening recessive genetic disease in the Caucasian population. This multiorgan disease is caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein, a chloride channel recognized as regulating several apical ion channels. The gene mutations result either in the lack of the protein at the apical surface or in an improperly functioning protein. Morbidity and mortality because of the mutation of CFTR are mainly attributable to lung disease resulting from chronic infection and inflammation. Since its discovery as the causative gene in 1989, much progress has been achieved not only in clinical genetics but also in basic science studies. Recently, combinations of these efforts have been successfully translated into development and availability for patients of new therapies targeting specific CFTR mutations to correct the CFTR at the protein level. Current technologies such as next gene sequencing and novel genomic editing tools may offer new strategies to identify new CFTR variants and modifier genes, and to correct CFTR to pursue personalized medicine, which is already developed in some patient subsets. Personalized medicine or P4 medicine ("personalized," "predictive," "preventive," and "participatory") is currently booming for CF. The various current and future challenges of personalized medicine as they apply to the issues faced in CF are discussed in this review.

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65 A p.Ala455Glu (A455E) 0.3% c.1585-1G , A - (1717-1G , A) 0.89% c.2052delA p.Lys684AsnfsX38 (2184delA) 0.16% c.3484C . Login to comment

[hide] The improvement of the best practice guidelines fo... Eur J Hum Genet. 2015 May 27. doi: 10.1038/ejhg.2015.99. Girardet A, Viart V, Plaza S, Daina G, De Rycke M, Des Georges M, Fiorentino F, Harton G, Ishmukhametova A, Navarro J, Raynal C, Renwick P, Saguet F, Schwarz M, SenGupta S, Tzetis M, Roux AF, Claustres M
The improvement of the best practice guidelines for preimplantation genetic diagnosis of cystic fibrosis: toward an international consensus.
Eur J Hum Genet. 2015 May 27. doi: 10.1038/ejhg.2015.99., [PMID:26014425]

Abstract [show]
Cystic fibrosis (CF) is one of the most common indications for preimplantation genetic diagnosis (PGD) for single gene disorders, giving couples the opportunity to conceive unaffected children without having to consider termination of pregnancy. However, there are no available standardized protocols, so that each center has to develop its own diagnostic strategies and procedures. Furthermore, reproductive decisions are complicated by the diversity of disease-causing variants in the CFTR (cystic fibrosis transmembrane conductance regulator) gene and the complexity of correlations between genotypes and associated phenotypes, so that attitudes and practices toward the risks for future offspring can vary greatly between countries. On behalf of the EuroGentest Network, eighteen experts in PGD and/or molecular diagnosis of CF from seven countries attended a workshop held in Montpellier, France, on 14 December 2011. Building on the best practice guidelines for amplification-based PGD established by ESHRE (European Society of Human Reproduction and Embryology), the goal of this meeting was to formulate specific guidelines for CF-PGD in order to contribute to a better harmonization of practices across Europe. Different topics were covered including variant nomenclature, inclusion criteria, genetic counseling, PGD strategy and reporting of results. The recommendations are summarized here, and updated information on the clinical significance of CFTR variants and associated phenotypes is presented.European Journal of Human Genetics advance online publication, 27 May 2015; doi:10.1038/ejhg.2015.99.

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78 Table 1 Examples of common CF-causing, indetermined, and non CF-causing variants (modified from5,8,17) HGVS nomenclature Legacy name cDNA nucleotide name Protein name CF-causing variantsa F508del c.1521_1523delCTT p.Phe508del G542X c.1624G4T p.Gly542* G551D c.1652G4A p.Gly551Asp N1303K c.3909C4G p.Asn1303Lys W1282X c.3846G4A p.Trp1282* 621+1G4T c.489+1G4T CFTRdele2,3 c.54-5940_273 +10250del21080 p.Ser18Argfs*16 E60X c.178G4T p.Glu60* G85E c.254G4A p.Gly85Glu 394delTT c.262_263delTT p.Leu88Ilefs*22 711+1G4T c.579+1G4T R347P c.1040G4C p.Arg347Pro A455E c.1364C4A p.Ala455Glu Q493X c.1477C4T p.Gln493* I507del c.1519_1521delATC p.Ile507del R553X c.1657C4T p.Arg553* R560T c.1679G4C p.Arg560Thr 1898+1G4A c.1766+1G4A 2183AA4G c.2051_2052delAAinsG p.Lys684Serfs*38 2789+5G4A c.2657+5G4A 3120+1G4A c.2988+1G4A M1101K c.3302 T4A p.Met1101Lys R1162X c.3484C4T p.Arg1162* 3659delC c.3528delC p.Lys1177Serfs*15 M1V c.1 A4G p.? Login to comment

[hide] Prevalence of meconium ileus marks the severity of... Genet Med. 2015 Jun 18. doi: 10.1038/gim.2015.79. Dupuis A, Keenan K, Ooi CY, Dorfman R, Sontag MK, Naehrlich L, Castellani C, Strug LJ, Rommens JM, Gonska T
Prevalence of meconium ileus marks the severity of mutations of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene.
Genet Med. 2015 Jun 18. doi: 10.1038/gim.2015.79., [PMID:26087176]

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RATIONALE: Meconium ileus (MI) is a perinatal complication in cystic fibrosis (CF), which is only minimally influenced by environmental factors. We derived and examined MI prevalence (MIP) scores to assess CFTR phenotype-phenotype correlation for severe mutations. METHOD: MIP scores were established using a Canadian CF population (n = 2,492) as estimates of the proportion of patients with MI among all patients carrying the same CFTR mutation, focusing on patients with p.F508del as the second allele. Comparisons were made to the registries from the US CF Foundation (n = 43,432), Italy (Veneto/Trentino/Alto Adige regions) (n = 1,788), and Germany (n = 3,596). RESULTS: The prevalence of MI varied among the different registries (13-21%). MI was predominantly prevalent in patients with pancreatic insufficiency carrying "severe" CFTR mutations. In this severe spectrum MIP scores further distinguished between mutation types, for example, G542X (0.31) with a high, F508del (0.22) with a moderate, and G551D (0.08) with a low MIP score. Higher MIP scores were associated with more severe clinical phenotypes, such as a lower forced expiratory volume in 1 second (P = 0.01) and body mass index z score (P = 0.04). CONCLUSIONS: MIP scores can be used to rank CFTR mutations according to their clinical severity and provide a means to expand delineation of CF phenotypes.Genet Med advance online publication 18 June 2015Genetics in Medicine (2015); doi:10.1038/gim.2015.79.

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63 Canadian studies for CF modfier genes 2,492 3,153 43,432 3,596 1,788 2,230 23,397 16,023 3 716 3,438 860 15% (19%) 1,902 2,576 PIP and MIP derivation FEV1 and zBMI modeling MIP calculation following correction of MI variable 23,301 2,413 510 21% (25%) 20% (23%) 13% (15%) Total F508del/others MI prevalence uncorrected (estimated) Missing or incomplete genotype Available for analysis Canadian CF patient registry, born after 1980 US CF patient registry German CF patient registry CF patient registry, North Italy Table 1ߒ Meconium ileus prevalence scores for the most common cystic fibrosis-causing variants p. F508del/other variants Class PIP Canada, (n) MIP, (n) Canada United States Germany Italy HGVS Legacy name c.262_263delTT 394delTT I 0.38 (50) c.3472C>T R1158X I 0.37 (35) c.1558G>T V520F 0.35 (43) c.3484C>T R1162X I 0.34 (135) 0.17 (14) 0.22 (45) c.2012delT 2143delT I 0.33 (13) c.3276C>A or G Y1092X I 0.92 (13) 0.09 (12) 0.33 (55) c.3846G>A W1282X I 1.00 (13) 0.29 (13) 0.32 (442) 0.17 (20) c.1477C>T Q493X I 1.00 (11) 0.19 (11) 0.32 (102) c.3528delC 3659delC I 0.31 (139) c.579ߙ+ߙ1G>T 711ߙ+ߙ1G>T 0.97 (39) 0.30 (38) 0.31 (54) c.178G>T E60X I 0.30 (66) c.1657C>T R553X I 1.00 (16) 0.28 (16) 0.30 (415) 0.24 (107) c.1585-1G>A 1717-1G>A I 1.00 (12) 0.23 (12) 0.29 (367) 0.22 (38) 0.16 (22) c.1766ߙ+ߙ1G>A 1898ߙ+ߙ1G>A 0.29 (139) c.1624G>T G542X I 0.99 (73) 0.31 (72) 0.29 (976) 0.21 (79) 0.22 (33) c.1521_1523delCTT F508del II 0.99 (1292) 0.22 (1260) 0.27 (15391) 0.21 (1910) 0.20 (230) c.1679G>C R560T II 0.27 (123) c.3744delA 3876delA 0.27 (22) c.2128A>T K710X I 0.26 (12) c.1519_1521delATC I507del II 1.00 (20) 0.21 (19) 0.25 (162) c.3909C>G N1303K II 0.98 (40) 0.13 (39) 0.25 (534) 0.23 (80) 0.14 (62) c.489ߙ+ߙ1G>T 621ߙ+ߙ1G>T I 1.00 (90) 0.24 (88) 0.25 (369) 0.21 (11) c.3266G>A W1089X I 0.25 (17) c.1675G>A A559T 0.24 (21) c.988G>T G330X 0.24 (10) c.3773_3774insT 3905insT 0.23 (78) c.2988ߙ+ߙ1G>A 3120ߙ+ߙ1G>A 0.22 (121) c.443T>C I148T;3199del6 1.00 (15) 0.22 (15) c.2052delA 2184delA I 0.21 (89) 0.22 (10) c.2051_2052delAAinsG 2183AA>G 0.20 (73) 0.20 (42) c.948delT 1078delT 0.19 (20) c.1652G>A G551D III 0.96 (54) 0.08 (53) 0.15 (979) 0.09 (84) c.254G>A G85E 0.50 (24) 0.06 (24) 0.14 (137) 0.00 (10) c.3196C>T R1066C 0.14 (42) c.1466C>A S489X 1.00 (14) 0.14 (14) c.3808G>A D1270N 0.13 (19) c.1055G>A R352Q 0.12 (18) c.579ߙ+ߙ5G>A 711ߙ+ߙ5G>A 0.12 (30) c.2175_2176insA 2307insA 0.11 (24) c.349C>T R117C 0.10 (37) c.1040G>C R347P IV 0.18 (11) 0.19 (11) 0.10 (130) 0.02 (56) c.350G>A R117H IV 0.05 (21) 0.00 (21) 0.07 (666) 0.02 (19) c.2657ߙ+ߙ5G>A 2789ߙ+ߙ5G>A V 0.25 (20) 0.00 (20) 0.06 (271) 0.01 (21) c.1040G>A R347H 0.06 (55) c.2988G>A 3120G->A 0.06 (36) c.328G>C D1152H IV 0.06 (124) c.3717ߙ+ߙ12191C>T 3849ߙ+ߙ10kbC>T V 0.07 (14) 0.00 (14) 0.05 (299) 0.01 (42) 0.00 (15) c.1364C>A A455E V 0.16 (45) 0.01 (41) 0.05 (109) c.1000C>T R334W IV 0.18 (11) 0.00 (10) 0.05 (92) c.617T>G L206W 0.06 (18) 0.05 (17) 0.04 (52) c.3302T>A M1101K 0.04 (17) c.200C>T P67L V 0.07 (14) 0.00 (14) Meconium ileus prevalence (MIP) and pancreas insufficiency prevalence (PIP) scores are presented. Login to comment
109 While non-CFTR modifier genes as well as environmental factors largely influence the development and progression of lung disease and nutritional decline,33-36 we demonstrate that the severity of the underlying CFTR genotype Table 2ߒ Meconium ileus prevalence scores and CFTR function CFTR mutation MIP score CFTR function (%wt) High MIP score ߓ V520F 0.38 0.2 ߓ N1303K 0.25 0.5 ߓ F508del 0.27 0.4 ߓ R560T 0.27 0.1 ߓ A559T 0.24 0 ߓ G551D 0.15 1 ߓ G85E 0.14 0.8 ߓ R1066C 0.13 0 Low MIP score ߓ R347P 0.1 0 ߓ R117C 0.1 2.9 ߓ R117H 0.07 33 ߓ R347H 0.06 5 ߓ R334W 0.05 1.3 ߓ A455E 0.05 6 ߓ L206W 0.04 5 ߓ M1101K 0.04 0 ߓ P67L 0.0 8 The table compares meconium ileus prevalence (MIP) scores and measured cystic fibrosis transmembrane conductance regulator (CFTR) function in Fisher rat thyroid determined by VanGoor et al.24 for the major and missense cystic fibrosis-causing variants for which patient group size was ࣙ10 in at least the US group. Login to comment

[hide] Searching for a cure for cystic fibrosis. A 25-yea... Eur J Pediatr. 2015 Nov 14. Bosch B, De Boeck K
Searching for a cure for cystic fibrosis. A 25-year quest in a nutshell.
Eur J Pediatr. 2015 Nov 14., [PMID:26567541]

Abstract [show]
After 25 years of intensive search, there is not yet a cure for cystic fibrosis (CF). However, the quest has led to major breakthroughs in understanding the basic disease defect and defining strategies to correct it. The first cystic fibrosis transmembrane conductance regulator (CFTR) modulators have been introduced in clinic. Some show an impressive clinical benefit, like the potentiator ivacaftor for the 4 % of patients with a class III defect. Others offer at present only a limited benefit, like the combination corrector lumacaftor plus potentiator ivacaftor for subjects homozygous for F508del. These findings prove that the basic defect in CF can be modified and hold the promise that one day CF will no longer be a life-shortening disease. CONCLUSION: This review updates the clinician on recent achievements as well as on the CF research pipeline. What is Known: * Cystic fibrosis (CF) is a common and life-shortening disease that currently cannot be cured. * However, for each of the six CF mutation classes, disease-modifying drugs are under way. What is New: * This review is a concise update for the clinician on new drugs that reached the CF clinical pipeline. * The research strategies in CF have become a paradigm for clinical trials in other inherited diseases.

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48 Table 1 CF mutation classes and a potential approach for correcting the defect Mutation class CFTR defect result Mutation type Mutation example Potential therapy Mutation class Specific Aspecific I No full-length CFTR Premature stop codon, Large deletions, Out-of-frame deletions or insertions G524X, W1282X Read-through (e.g. ataluren) RNA correction Gene therapy II Processing defect Missense, amino acid deletion F508del, N1303K, 1507del Corrector III Regulation defect Missense G551D Potentiator (e.g. ivacaftor) IV Decreased conductance Missense R117H Potentiator V Reduced synthesis Missense, change in splicing efficiency 3849+10 kb C࢐G, A455E, 5 T Corrector (e.g. VX-809) Potentiator VI Altered channel stability Nonsense, frameshift 4326 delTC, 4279insA Potentiator Proteastasis inhibitor In class I mutation, no protein reaches the plasma membrane as transcription is halted prematurely in the case of premature stop codons or the protein is non-functional in the case of large deletions or out-of-frame deletions or insertions); in class II mutations, a block in protein folding and trafficking leads to protein degradation in the proteasome; class III mutations lead to a protein with defective channel regulation; in class IV, the CFTR channel has an altered conductance; in class V, the amount of CFTR channels synthetized present at the cell membrane is reduced; class VI mutations lead to a functional but less stable protein in the apical cell membrane. Login to comment

[hide] Gene therapy for the respiratory manifestations of... Am J Respir Crit Care Med. 1995 Mar;151(3 Pt 2):S75-87. Korst RJ, McElvaney NG, Chu CS, Rosenfeld MA, Mastrangeli A, Hay J, Brody SL, Eissa NT, Danel C, Jaffe HA, et al.
Gene therapy for the respiratory manifestations of cystic fibrosis.
Am J Respir Crit Care Med. 1995 Mar;151(3 Pt 2):S75-87., [PMID:7533609]

Abstract [show]
Cystic fibrosis (CF) is caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The major manifestations are on the airway epithelial surface, with purulent mucus, recurrent infections, chronic inflammation, and loss of lung function. Consequent to mutations in both parental genes, airway epithelial cells have insufficient CFTR function. Because this can be corrected in vitro by transfer of the normal CFTR gene into airway epithelial cells, it is reasonable to hypothesize that the respiratory manifestations of CF could be prevented by transfer of the normal human CFTR cDNA to the airway epithelium in vivo. Over the past 6 years, our laboratory has developed a strategy to accomplish this goal using a replication deficient E1-E3- recombinant adenovirus (Ad) serotype 5 vector containing the normal human CFTR cDNA (AdCFTR). Studies with experimental animals demonstrate that with administration of such a vector to the airways, the human CFTR cDNA could be transferred to the airway epithelium, with expression of the human CFTR cDNA for at least 6 weeks. Extensive preclinical studies in vitro and in vivo demonstrated that the risks to humans were sufficiently low to initiate a Phase I trial using the AdCFTR vector to treat the respiratory manifestations of CF in humans. Following approval by the National Heart, Lung, and Blood Institute Institutional Review Board, the National Institutes of Health Biosafety Committee, the National Institutes of Health Recombinant DNA Advisory Committee, and the Food and Drug Administration, we initiated the first human trial of gene therapy for CF on April 17, 1993. The clinical study is still ongoing, with safety and efficacy data being evaluated, but there is clear evidence that it is feasible to transfer and express the normal CFTR cDNA to the airway epithelium in vivo in individuals with CF.

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99 Alleles G551D, S5491, A455E, and G542X account for 10-20% of the non-L\F508 mutations. Login to comment