ABCMdb

ABCC7 p.Phe508Cys

ClinVar:	c.1523T>C , p.Phe508Ser ? , not provided c.1523T>G , p.Phe508Cys N , Benign
CF databases:	c.1521_1523delCTT , p.Phe508del D , CF-causing c.1523T>C , p.Phe508Ser (CFTR1) D , This mutation was found in a patient with CBAVD. c.1523T>G , p.Phe508Cys (CFTR1) ? ,
Predicted by SNAP2:	A: D (95%), C: D (75%), D: D (95%), E: D (95%), G: D (95%), 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 (95%), T: D (95%), V: D (95%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D,

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[hide] Complete mutational screening of the cystic fibros... Hum Reprod. 1999 Dec;14(12):3035-40. Pallares-Ruiz N, Carles S, Des Georges M, Guittard C, Arnal F, Humeau C, Claustres M
Complete mutational screening of the cystic fibrosis transmembrane conductance regulator gene: cystic fibrosis mutations are not involved in healthy men with reduced sperm quality.
Hum Reprod. 1999 Dec;14(12):3035-40., [PMID:10601093]

Abstract [show]
Based on the analysis of the most frequent mutations responsible for cystic fibrosis (CF), a higher than expected frequency of CF mutations was recently reported in men with infertility due to reduced sperm quality. To further document whether this condition is associated with severe or mild abnormalities of cystic fibrosis transmembrane conductance regulator (CFTR) functions, we carried out a complete scanning of CFTR sequences using a strategy that detects almost all 850 mutations and 150 polymorphisms reported to date in the CFTR gene. We have investigated a cohort of 56 patients with severe oligoasthenoteratozoospermia (OAT) and 50 controls from southern France for CFTR gene mutations and variations. The frequencies of CF-causing mutations and CFTR variations identified in this OAT sample did not differ significantly from the frequencies found in the normal population. However, we observed a 1.7-fold increase in the proportion of homozygotes for a specific CFTR haplotype (TG11-T7-G1540) in the OAT group (P = 0.025). Our results do not confirm a link between CF mutations and reduced sperm quality. Further studies are needed to substantiate the hypothesis that a combination of variants affecting expression and function of the CFTR protein is associated with male infertility.

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45 Six variants present on using an improved procedure derived from a previously described OAT alleles, 1655T/G (F508C), 1716G/A (E528E), 2377C/T method (Chillon et al., 1995). Login to comment
63 Frequency distribution of CFTR gene variants in populations from southern France infertile men with OAT and in controls (T)n-1540A/G-(TG)n Controls OAT PVariants Allele frequency, % of chromosomes (n ϭ 50) (n ϭ 56) Controls CBAVDa OAT 9/9 A/A 10/10 1 (2) 1 (2) NS(n ϭ 100) (n ϭ 100) (n ϭ 112) 7/9 A/A 10/12 1 0 11/10 0 1223C/T (R31C) 0.01 0 0 10/10 0 3356G/A (R75Q) 0.02 0.01 0.009 Total 1 (2) 4 (7) NS1655T/G (F508C) 0 0.01 0.009 7/9 A/G 11/10 2 41716 G/A (E528E) 0 0.01 0.018 10/12 5 21859G/C (G576A)ϩ2134C/T 0.01 0.04c 0.009 7 (14) 6 (11) NS(R668C)b 7/7 A/A 12/12 0 12377C/T (L749L) 0 0.01d 0.009 11/12 1 03417A/T (T1095T) 0.01 0 0.018 10/11 3 03419T/G (L1096R) 0.01 0 0 10/10 1 44002A/G (P1290P) 0.01 0 0.018 Total 5 (10) 5 (9) NS4404C/T (T1424T) 0.01 0.01 0.018 7/7 A/G 12/12 0 2125G/C (5ЈUTR) 0.07 0.01 0.027 11/12 0 3405ϩ46G/T 0 0 0.018 11/11 5 0406-6T/C 0.01 0 0 10/11 3 3875ϩ40A/G 0.05 0.06 0.045 10/10 8 03041-71G/Cϩ4002A/Gb 0.02 0.02 0.009 Total 16 (32) 8 (14) NS3499ϩ37G/A 0 0 0.009 7/7 G/G 11/11 16 (32) 31 (55) Ͻ 0.024374ϩ13A/G 0 0 0.009 8/11 0 1 Total 16 (32) 32 (57) 0.018aGroup of CBAVD patients whose genotypes had been previously analysed 7/5 A/G 11/11 2 (4) 0 -in our laboratory. Login to comment
75 Several missense variations identified in this study (R31C, R75Q, F508C, G576A, R668C, or E528E) have previously Table IV. Login to comment
84 (for instance F508C associated in trans with ∆F508 (Desgeorges et al., 1994). Login to comment
129 Desgeorges, M., Kjelleberg, P., Demaille, J. et al. (1994) A healthy male with compound and double heterozygosities for ∆F508, F508C, and M470V in exon 10 of the cystic fibrosis gene. Login to comment
146 Mol. Hum. Reprod., 3, 419-430. Meschede, D., Eigel, A., Horst, J. et al. (1993) Compound heterozygosity for the ∆F508 and F508C cystic fibrosis transmembrane conductance regulator (CFTR) mutations in a patient with congenital bilateral aplasia of the vas deferens. Am. J. Hum. Genet., 53, 292-293. Meschede, D., Dworniczak, B., Behre, H.M. et al. (1997) CFTR gene mutations in men with bilateral ejaculatory-duct obstruction and anomalies of the seminal vesicles. Login to comment

[hide] Rapid F508del and F508C assay using fluorescent hy... Genet Test. 1999;3(4):365-70. Gundry CN, Bernard PS, Herrmann MG, Reed GH, Wittwer CT
Rapid F508del and F508C assay using fluorescent hybridization probes.
Genet Test. 1999;3(4):365-70., [PMID:10627945]

Abstract [show]
Amplification and fluorescent genotyping of the cystic fibrosis F508del locus was achieved from human genomic DNA in less than 30 min. The hybridization of adjacent fluorescent probes at the mutation site was monitored by resonance energy transfer between fluorescein and Cy5 during heating or cooling. Characteristic curves were obtained for each genotype; the first derivative of these fluorescent curves has a maximum at an apparent hybridization temperature (Tm) that is specific for each probe/allele duplex. The direction and rate of temperature change determines the difference between the apparent Tm and the true equilibrium Tm. One hundred and five sample were genotyped for the F508del cystic fibrosis mutation by heating and cooling curve profiles. These genotypes were validated by allele-specific amplification. Two fluorescein hybridization probes were designed to match the wild-type sequence perfectly from either codons 502 to 513 or from 504 to 511 on the cystic fibrosis transconductance regulator gene of chromosome 7. While genotyping for the F508del, an allele with the F508C base change was detected. For both F508del and F508C variants, the Tm shift from wild type was greater with a 24-mer probe than with a 35-mer probe. Fluorescent monitoring of hybridization probes is a versatile technique that can detect unexpected sequence alterations.

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51 Ittttcctggattatgcctggcaccattaai |gaaaatatcatct/\tggtgtttccI A F508C _Sf2_ FIG 1 Schematic of the adjacent hybridization probe design. Login to comment
55 The raised T in the 24-mer probe designates the position of the nucleotide creating a single base-pair mismatch when hybridized to the F508C alíele. Login to comment
59 Either probe set can be used to genotype the wild type, F508del, and F508C alíeles, although the shorter probe set results in the best discrimination (see text). Login to comment
98 This is a known and single nucleotide base change resulting in a phenylalanine to cysteine amino acid substitution (F508C) that has been indicated as a factor in male sterility (Meschede et al, 1993; Dörk et al, 1997). Login to comment
99 The F508C variant created a T:C mismatch which was positioned exactly in the center of the 35-mer probe and 11 bp in from the 5'-end of the 24-mer probe (Fig. 1). Login to comment
101 Figure 4 compares derivative melting peaks for the wild-type, F508del, and F508C alíeles. Login to comment
105 Genotyping the F508del and F508C variants by derivative fluorescent heating curves using a 24-mer Cy5-labeled probe. Login to comment
106 The samples shown are as follows: heterozygous F508del (-), heterozygous F508C (- • -), and no template control ( • ••). Login to comment
113 The method is specific for different variants as shown by the ability to discriminate between the F508del mutation and the F508C base change. Login to comment
115 Apparent Melting Temperature of Probe/Allele Duplexes Apparent Tm (°Cf Allele 35-mer 24-mer F508del F508C Wild type 61.6 64.6 68.6 53.8 59.0 64.0 "Apparent melting temperature at a heating rate of 0.1 °C/sec. Login to comment

[hide] Branch migration inhibition in PCR-amplified DNA: ... Nucleic Acids Res. 2000 May 1;28(9):E42. Lishanski A, Kurn N, Ullman EF
Branch migration inhibition in PCR-amplified DNA: homogeneous mutation detection.
Nucleic Acids Res. 2000 May 1;28(9):E42., 2000-05-01 [PMID:10756209]

Abstract [show]
A novel method for detection of any mutation located within a PCR-amplified DNA sequence was demonstrated. The method is based on the inhibition of spontaneous DNA branch migration. Partial duplexes produced by PCR amplification of a test and a reference genomic DNA sample anneal to form four-stranded cruciform structures. Spontaneous DNA branch migration results in dissociation of these structures when the test and reference sequences are identical. Any base substitution, deletion or insertion inhibits branch migration and produces stable cruciform structures. When suitable ligands are attached to the PCR primers, the cruciform structures can be detected by standard immunochemical methods. This approach was tested using several commonly occurring mutations within the human cystic fibrosis gene. New methods for increasing the specificity of PCR amplifications are described that were used for successful mutation analysis.

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106 Genotype LOCI without reference DNA LOCI with reference DNA ELISA without reference DNA Wild-type homozygotes wt/wt 2.5 (2.1) 2.3 9.4 wt/wt 2.3 (3.2) 2.9 7.4 wt/wt 2.4 (2.4) 3.7 8.2 wt/wt 2.1 (2.7) 3.1 7.6 Heterozygotes ∆F508/wt 3 bp deletion 61 (100) 53 63 ∆F508/wt 3 bp deletion 105 (109) 102 102 ∆F508/wt 3 bp deletion 110 (114) 94 108 ∆F508/wt 3 bp deletion 138 (147) 119 136 ∆I508/wt 3 bp deletion 107 (76) 96 116 F580C/wt T→G 95 (57) 87 92 ∆F508/F508C 3 bp deletion/T→G 93 (85) 139 97 ∆F508/F508C 3 bp deletion/T→G 90 (113) 111 86 Mutant homozygotes ∆F508/∆F508 3 bp deletion 2.6 (3.2) 149 6.7 ∆F508/∆F508 3 bp deletion 2.0 (3.2) 184 7.4 ∆F508/∆F508 3 bp deletion 2.4 (2.1) 181 7.8 ∆F508/∆F508 3 bp deletion 2.2 (3.0) 212 7.9 Blank (no target DNA) 1.2 6.7 v sample and re-measured to identify homozygous mutants (homozygote screen). 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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No. Sentence Comment
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] Molecular screening of the CFTR gene in men with a... Mol Hum Reprod. 2000 Dec;6(12):1063-7. Jezequel P, Dubourg C, Le Lannou D, Odent S, Le Gall JY, Blayau M, Le Treut A, David V
Molecular screening of the CFTR gene in men with anomalies of the vas deferens: identification of three novel mutations.
Mol Hum Reprod. 2000 Dec;6(12):1063-7., [PMID:11101688]

Abstract [show]
Many studies have shown that congenital absence of the vas deferens (CAVD) is a genital cystic fibrosis transmembrane conductance regulator (CFTR)-mediated phenotype, with a broad spectrum of abnormalities causing male infertility. The genotype of these patients includes mutations in the CFTR gene, e.g. DeltaDeltaF508, R117H and the T5 allele; all of which are commonly found in CAVD. In this study we have screened the entirety of CFTR gene in 47 males with anomalies of the vas deferens: 37 cases of congenital bilateral absence of the vas deferens, three cases of congenital unilateral absence of the vas deferens and seven cases of obstructive azoospermia with hypoplastic vas deferens. Among the 94 chromosomes studied, 65 mutations, of which three are novel (2789+2insA, L1227S, 4428insGA), were identified. The majority of patients (63.8%) had two detectable CFTR gene mutations. Furthermore, high frequencies of the DeltaDeltaF508 mutation (44.7%), the T5 allele (36.2%) and R117H mutation (19.1%) were observed.

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106 Meschede, D., Eigel, A., Horst, J. et al. (1993) Compound heterozygosity for J. Am. Med. Assoc., 267, 1794-1797. the ∆F508 and F508C cystic fibrosis transmembrane conductance regulator Beck, S., Penque, D., Garcia, S. et al. (1999) Cystic fibrosis patients with the (CFTR) mutations in a patient with congenital bilateral aplasia of the vas 3272-26A→G mutation have mild disease, leaky alternative mRNA deferens. Am. J. Hum. Genet., 53, 292-293. splicing, and CFTR protein at the cell membrane. 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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55 The 70-mutation assay distinguished between the ⌬F508 mutation and the F508C sequence variant. Login to comment
56 The 86-mutation assay distinguished ⌬F508 from the F508C, I506V, I506M, and I507V sequence variants. 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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592 At the other extreme, for example, the mutations I506M and F508C, which occur in stringently conserved residues in the functionally important NBD1, have also been confirmed to be nonfunctional variants (Kobayashi et al. 1990; Kalin, Dork, and Tummler 1992; Will et al. 1992). 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]

Abstract [show]
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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55 Patients were also screened for CFTR variants in intron 8 (5T, 7T and 9T) and polymorphisms F508C, I506V and I507V. 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
76 Sample 6 was correctly genotyped as a compound heterozygote for the common CF mutation ⌬F508 and the polymorphism F508C. 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
98 On the other hand, the ⌬F508 mutation is the most common CF allele, and three polymorphisms (I506V, I507V, and F508C) can interfere with hybridization of the wild-type oligonucleotide sequence. Login to comment
99 Thus, the presence of oligonucleotides corresponding to the three polymorphisms in the Research Prototype Cystic Fibrosis Assay-31 test avoids misdiagnosis of ⌬F508/I506V, I507V, or F508C compound heterozygotes. 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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181 It is critical that laboratories include known variants in the mutation panel to prevent mistyping of compound genotypes such as F508C/⌬F508. Login to comment
217 As for ASO typing, it is critical to include frequent polymorphisms in the coding region of the CFTR gene, e.g., F508C, to prevent mistypings of polymorphism/mutant compound heterozygous genotypes such as F508C/⌬F508. Login to comment
311 For example, I506 V and F508C are performed as reflex tests for ⌬F508 positives unless it is proven that these variants do not cause assay interference. 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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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] 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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184 For example, wild-type probes for I506V and I507V share common sequences with the ⌬F508 probe, and ⌬I507 and F508C have identical wild-type sequence (see Table 2 in the online Data Supplement); this is not surprising because they detect mutations on three contiguous codons. Login to comment
185 As a consequence, when the ⌬F508/⌬F508 homozygous mutant sample was tested the F508C, ⌬I507, I506V, and I507V wild-type probes all lost activity, and in the case of the I506V/⌬F508 compound heterozygote, the I507V wild-type probe lost activity. Login to comment

[hide] Detection of five common CFTR mutations by rapid-c... Clin Chem. 2004 Apr;50(4):773-5. Dempsey E, Barton DE, Ryan F
Detection of five common CFTR mutations by rapid-cycle real-time amplification refractory mutation system PCR.
Clin Chem. 2004 Apr;50(4):773-5., [PMID:15044340]

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21 The F508del ARMS primers (CF-DFjN and CF-DFwM) are specific for this mutation and are not influenced by the benign I506V and F508C mutations. 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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78 DNA Amplification and colorimetric detection on linear array strips with Analyte Specific Reagents for a 16-mutation assay (gift from Roche Molecular Systems, Alameda, CA) and a 27-mutation assay (Linear Array CF-31; Roche Molecular Biochemicals, Indianapolis, IN) were used.20 For both panels, the DNA assay assessed only CFTR mutations; detection of polymorphisms was incorporated as a reflex test for confirmation of putative ⌬F508 homozygotes (assay for F508C, I506V, and I507V) or for genotype elucidation on detection of 2 mutations including R117H (assay for IVS8polyT 5/7/9T). 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

[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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7 Key Words: cystic fibrosis, carrier screening, BeadChip technology Cystic fibrosis (CF) results from mutations in the CF transmembrane conductance regulator (CFTR) and is a common autosomal recessive disorder, particularly in individuals of Caucasian and Ashkenazi Jewish (AJ) ancestry.1,2 CF also affects individuals from other ethnic groups, including Hispanics, African Americans, and Asians with carrier frequencies ranging from 1in46to1in90.1 Morethan1000mutationshavebeendescribed in the CFTR gene and although many of them are private mutations, there are a number of mutations that are distributed worldwide and still others that are common to specific ethnic groups.3 In2001,theAmericanCollegesofMedicalGenetics(ACMG)and Obstetrics and Gynecologists (ACOG) established guidelines for prenatal carrier testing for CF that included a panel of 25 panethnic mutations with allele frequencies Ն 0.1% among CF patients inNorthAmerica.1,4 Inaddition,theyrecommendedthatcarriers of R117H be subsequently tested for the 5/7/9T polymorphic alleles in intron 8 and that individuals positive for delF508 and delI507 have reflex testing for interference from the benign variants F508C, I506V, and I507V.1 The ACMG/ACOG recommendations precipitated a dramatic increase in the number of CF tests performed in genetic testing laboratories. Login to comment
49 Reflex testing of delF508 and delI507 positive samples for the F508C, I506T, and I507T variants was not necessary with this methodology. Login to comment
105 Genomic DNA from an F508C and an I506V carrier were amplified with the Group I multiplex primer mix and analyzed using the BeadChip assay system. Login to comment
108 In addition, the PCR products amplified from the genomic DNA of F508C and I506V carriers and the single-stranded oligonucleotides for the I507V and I506M only elongated from the normal probe indicating that these variants did not interfere with allele discrimination. Login to comment

[hide] A large-scale study of the random variability of a... Eur J Hum Genet. 2005 Feb;13(2):184-92. Modiano G, Bombieri C, Ciminelli BM, Belpinati F, Giorgi S, Georges M, Scotet V, Pompei F, Ciccacci C, Guittard C, Audrezet MP, Begnini A, Toepfer M, Macek M, Ferec C, Claustres M, Pignatti PF
A large-scale study of the random variability of a coding sequence: a study on the CFTR gene.
Eur J Hum Genet. 2005 Feb;13(2):184-92., [PMID:15536480]

Abstract [show]
Coding single nucleotide substitutions (cSNSs) have been studied on hundreds of genes using small samples (n(g) approximately 100-150 genes). In the present investigation, a large random European population sample (average n(g) approximately 1500) was studied for a single gene, the CFTR (Cystic Fibrosis Transmembrane conductance Regulator). The nonsynonymous (NS) substitutions exhibited, in accordance with previous reports, a mean probability of being polymorphic (q > 0.005), much lower than that of the synonymous (S) substitutions, but they showed a similar rate of subpolymorphic (q < 0.005) variability. This indicates that, in autosomal genes that may have harmful recessive alleles (nonduplicated genes with important functions), genetic drift overwhelms selection in the subpolymorphic range of variability, making disadvantageous alleles behave as neutral. These results imply that the majority of the subpolymorphic nonsynonymous alleles of these genes are selectively negative or even pathogenic.

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33 In the Tajima`s test,19 the null hypothesis of neutrality is rejected if a statistically significant difference between p Common and rare nonsynonymous and synonymous cSNSs G Modiano et al European Journal of Human Genetics Table 1 List of the 61 cSNSsa encountered in the present survey The random samples of genes (and the technique utilized) cSNS variants found NE Italy (DGGE) Central Italy (DGGE) Southern France (DGGE) Northern France (DHPLC) Spain (SSCA) Czechia (DGGE) Hb Â 104 Exon Exon Length (bp) Ref. no. SNS SASc 1st 100d 2nd 500 1st 100d 2nde 1st 100d 2nd 500 1st 100 2nde 82d 72 Abs. Freq. Total sample size q Â 104 se Â 104 NSf Sf 1g 53 0 0 0 0 0/452 0 924 2 111 1 223C4T R31C 1 1 1/500 1 1 0 0/450 0 5 (11) 1 932 (2 432) 45.23 13.61 90 2 224G4T R31L 0 0 0/500 0 0 0 1/450 0 1 1 932 5.17 5.17 10 3 257C4T S42F 0 0 1/500 0 0 0 0/450 0 1 1 932 5.17 5.17 10 3 109 4 334A4G K68E 1 0 0 0/498 0 0 0 0/452 0 0 1 2 504 3.99 3.99 8 5 352C4T R74W 0 0 0 0/498 0 0 0 1/452 0 0 1 2 504 3.99 3.99 8 6 356G4A R75Q 1 7 1 7/498 2 9 2 9/452 0 2 40 (40) 2 504 (2 544) 157.23 24.66 310 7 386G4A G85E 0 0 1 1/498 0 0 0 0/452 0 0 2 2 504 7.99 5.65 16 4 216 8 482G4A R117H 0 0 0 0/292 0 2 0 1/456 0 0 3 2 302 13.03 7.52 26 9 528T4G I132M 0 0 0 0/292 0 0 0 1/456 0 0 1 2 302 4.34 4.34 8 10 575T4C I148T 1 2 0 1/292 0 0 0 1/456 0 1 6 2 302 26.06 10.63 52 5 90 11 640C4T R170C 0 0 0 0/6 0 0 1/448 0 1 1 436 6.96 6.96 14 12 641G4A R170H 1 1 0 0/6 0 0 2/448 0 4 (4) 1 436 (1 930) 20.73 10.35 41 6a 164 0 0 0/6 0 0 0/432 0 0 992 6b 126 0 0 0/6 0 0 0/454 0 942 7 247 0 0 0/6 0 0 0/796 0 1 284 8 93 13 1281G4A L383 0 0 0 0/6 0 0 1/456 0 0 1 1 516 6.60 6.60 13 9 183 14 1402G4A G424S 0 0 0/6 0 0 1/454 0 1 940 10.64 10.64 21 15 1459G4T D443Y 0 0 0/6 0 0 1/454 0 1 940 10.64 10.64 21 10 192 16 1540A4G M470Vh 42 197 30 37/96 39 199 (i) (i) 27 571(736) 1 484 (1 912) 3849.37 111.28 4 735 17 1598C4A S489X 0 0 0 0/96 0 0 0 1/796 0 1 2 374 4.21 4.21 8 18 1648A4G I506V 1 0 0 0/96 0 0 0 0/796 0 1 2 374 4.21 4.21 8 19 1655T4G F508C 0 1 0 0/96 0 0 0 1/796 0 2 2 038 8.42 5.96 17 20 1716G4A Q528 2 16 1 0/96 0 19 i I 5 43 (58) 1 478 (2 024) 286.56 37.08 557 11 95 21 1756G4T G542X 0 2 0 0/134 0 0 0/796 0 0 2 1 984 10.08 7.12 20 22 1764T4G G544 0 0 0 0/134 0 0 1/796 0 0 1 1 984 5.04 5.04 10 23 1784G4A G551D 0 0 0 0/134 0 0 1/796 0 0 1 1 984 5.04 5.04 10 12 87 24 1816G4A V562I 0 0 0 0 1 0 0/450 0 0 1 (1) 2 004 (2 504) 3.99 3.99 8 25 1816G4C V562L 0 0 0 1 0 0 1/450 0 0 2 (3) 2 004 (2 504) 11.98 6.91 24 26 1859G4C G576A 1 2 0 1 11 0 8/450 0 0 23 (27) 2 004 (2 538) 106.38 20.36 213 13 724j 449 27 1997G4A G622D 0 0 0/80 0/96 1 0 0 0/444 0 1 2 002 5.00 5.00 10 28 2082C4T F650 1 0 0/80 0/20 0 0 0 0/444 0 1 (1) 1 926 (2 412) 4.15 4.15 8 29 2134C4T R668C 1 2 0/80 0/96 1 11 0 12/444 0 27(32) 2 002 (2 558) 125.10 21.98 247 275 30 2377C4T L748 0 0 0/6 0 1 1 388 25.77 25.77 52 14a 129 31 2670G4A W846X 0 0 0/6 0 1 0/452 0/80 0 1 1 010 9.90 9.90 20 32 2694T4G T854 33 23 0/6 33 38 149/452 14/80 11 301 1 010 2980.20 143.92 4 184 33 2695G4A V855I 0 0 0/6 0 0 1/452 0/80 0 1 1 010 9.90 9.90 20 14b 38 0 0 0 0/520 0 0 0 0/446 0 2 448 15 251 34 2816G4C S895T 0 0 0/6 0 0 2/436 0 0 2 996 20.08 14.18 40 35 2831A4C N900T 0 0 0/6 0 0 1/436 0 0 1 996 10.04 10.04 20 36 2988G4C M952I 0 0 0/6 0 0 1/436 0 0 1 996 10.04 10.04 20 37 3030G4A T966 (2)k (1)k 0 6/436 0 6 (25)k 618 (1814)k 137.82 27.37 272 38 3032T4C L967S 0 0 0/6 0 0 1/436 0 0 1 996 10.04 10.04 20 16 80 0 0 0/498 0 0 0/450 0 0 1 502 17a 151 39 3123G4C L997F 0 2 2 1/494 0 7 1 4/454 0 0 17 2 502 67.95 16.42 135 40 3157G4A A1009T 0 2 0 0/494 0 0 0 0/454 0 0 2 2 502 7.99 5.65 16 41 3212T4C I1027T 1 0 0 0/494 0 0 0 0/454 0 0 1 2 502 4.00 4.00 8 17b 228 42 3286T4G F1052V 1 1 0 1/194 0 0 0 0/452 0 0 3 (3) 2 200 (2 240) 13.39 7.73 27 43 3337G4A G1069R 0 1 0 0/194 0 0 0 0/452 0 0 1 2 200 4.55 4.55 9 CommonandrarenonsynonymousandsynonymouscSNSs GModianoetal 186 EuropeanJournalofHumanGenetics 44 3345G4T Q1071H 0 0 0 0/194 0 1 0 0/452 0 0 1 2 200 4.55 4.55 9 45 3417A4T T1995 1 3 0 0/194 1 1 0 0/452 0 0 6 (8) 2 200 (2 506) 31.92 11.27 64 46 3419T4G L1096R 0 0 0 0/194 1 0 0 0/452 0 0 1 2 200 4.55 4.55 9 47 3477C4A T1115 0 0 0 0/194 0 0 0 1/452 0 0 1 2 200 4.55 4.55 9 18 101 48 3523A4G I1131V 0 0 1 0/10 0 0 0/448 0 0 1 (2) 1 512 (1 908) 10.48 7.07 21 49 3586G4C D1152H 0 0 0 0/10 0 0 1/448 0 0 1 1 512 6.61 6.61 13 19 249 50 3617G4T R1162L 0 0 1 1/494 0 0/260 0 0/454 0 0 2 2 262 8.84 6.25 18 51 3690A4G Q1186 0 0 0 0/494 0 0/260 0 0/454 1 0 1 2 262 4.42 4.42 9 52 3813A4G L1227 0 1 0 0/494 0 0/260 0 0/454 0 0 1 2 262 4.42 4.42 9 53 3837T4G S1235R 1 1 0 1/494 0 4/260 0 7/454 0 1 15 (15) 2 262 (2 310) 69.94 16.71 140 20 156 54 4002A4G P1290 2 3 0/6 3 5 18/454 3/80 2 36 1 012 357.73 58.22 690 21 90 55 4009G4A V1293I 0 0 0/6 0 0/300 0 1/456 0 0 1 1 316 7.60 7.60 15 56 4029A4G T1299 1 0 0/6 0 1/300 0 1/456 0 0 3 (8) 1 316 (2 330) 34.33 12.12 69 57 4041C4G N1303K 1 0 0/6 0 0/300 0 0/456 0 0 1 1 316 7.60 7.60 15 58 4085T4C V1318A 0 0 0/6 0 0/300 0 1/456 0 0 1 1 316 7.60 7.60 15 22 173 0 0 0/18 0 0 0/450 0 0 1 022 23 106 0 0 0 0/6 0 0 0/448 0 1 436 24l 198+3 59 4404C4T Y1424 1 0 0/6 1 2 5/420 0 2 11 (32) 980 (2 516) 127.19 22.34 251 60m 4521G4A Q1463 (21) (16) (3/32) (14/80) (30) (94/420) 15/76 (17) 15 (227) 76 (1052) 2142.86 131.07 3 367 61 4563T4C D1477 0 0 0/6 0 1 0/420 0 0 1 980 10.20 10.20 20 Totals 6 525 9 584 16 109 The bracketed figures include also the RFLP analysis data (see Materials and methods); the NE Italy, Central Italy, Southern and Northern France are each subdivided into two samples where the 1st is made up of 100 genes. 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[hide] Side chain and backbone contributions of Phe508 to... Nat Struct Mol Biol. 2005 Jan;12(1):10-6. Epub 2004 Dec 26. Thibodeau PH, Brautigam CA, Machius M, Thomas PJ
Side chain and backbone contributions of Phe508 to CFTR folding.
Nat Struct Mol Biol. 2005 Jan;12(1):10-6. Epub 2004 Dec 26., [PMID:15619636]

Abstract [show]
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), an integral membrane protein, cause cystic fibrosis (CF). The most common CF-causing mutant, deletion of Phe508, fails to properly fold. To elucidate the role Phe508 plays in the folding of CFTR, missense mutations at this position were generated. Only one missense mutation had a pronounced effect on the stability and folding of the isolated domain in vitro. In contrast, many substitutions, including those of charged and bulky residues, disrupted folding of full-length CFTR in cells. Structures of two mutant nucleotide-binding domains (NBDs) reveal only local alterations of the surface near position 508. These results suggest that the peptide backbone plays a role in the proper folding of the domain, whereas the side chain plays a role in defining a surface of NBD1 that potentially interacts with other domains during the maturation of intact CFTR.

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90 The steady-state band C levels of F508C and F508M were reduced, but closest to those of wild type. Login to comment
92 The known polymorphism F508C and the non-CF-causing variant F508S both showed measurable quantities of band C at steady-state levels, as would be expected for non-CF-causingsubstitutions.Thehydrophobicaminoacidsubstitutions F508I,F508W and F508Y did not produce substantial steady-state levels of band C as measured by western blotting, nor did the ionizable amino acid substitutions F508D, F508E, F508K, F508H or F508R. Login to comment
113 W ild type ∆∆F508 F508 F508D F508K F508E F508R F508H F508S F508T F508N F508Q C B Charged Polar F508A F508C F508I F508L ∆F508 F508 W ild type C B F508W F508Y F508G F508P Hydrophobic F508M F508V ̅̆ ̆ ̅ Figure 3 Maturation of full-length CFTR mutants. 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] 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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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] 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] Haplotype block structure study of the CFTR gene. ... Eur J Hum Genet. 2006 Jan;14(1):85-93. Pompei F, Ciminelli BM, Bombieri C, Ciccacci C, Koudova M, Giorgi S, Belpinati F, Begnini A, Cerny M, Des Georges M, Claustres M, Ferec C, Macek M Jr, Modiano G, Pignatti PF
Haplotype block structure study of the CFTR gene. Most variants are associated with the M470 allele in several European populations.
Eur J Hum Genet. 2006 Jan;14(1):85-93., [PMID:16251901]

Abstract [show]
An average of about 1700 CFTR (cystic fibrosis transmembrane conductance regulator) alleles from normal individuals from different European populations were extensively screened for DNA sequence variation. A total of 80 variants were observed: 61 coding SNSs (results already published), 13 noncoding SNSs, three STRs, two short deletions, and one nucleotide insertion. Eight DNA variants were classified as non-CF causing due to their high frequency of occurrence. Through this survey the CFTR has become the most exhaustively studied gene for its coding sequence variability and, though to a lesser extent, for its noncoding sequence variability as well. Interestingly, most variation was associated with the M470 allele, while the V470 allele showed an 'extended haplotype homozygosity' (EHH). These findings make us suggest a role for selection acting either on the M470V itself or through an hitchhiking mechanism involving a second site. The possible ancient origin of the V allele in an 'out of Africa' time frame is discussed.

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30 The T2A rate was much lower than 1 Frequencies of the CFTR variants within the M or the V alleles exon or intron VARIANT SITES in the M genes (MM subjects) in the V genes (VV subjects) A 5' UTR 125 g/c 8/144 (0.056) 3/356 (0.008) -80 1 2 R31C 5/226 (0.004) 1/576 (0.002) -56 in M genes in V genes 6 2 R75Q 1/226 (0.004) 15/576 (0.026) -51 M V (ttga)n 0.461 0.017 7 3 G85E 0/226 (0) 1/576 (0.002) -51 2.214 0.362 (tg)n 0.616 0.114 B i 3 406-6 t/c 0/226 (0) 6/576 (0.010) -29 (t)n 0.499 0.036 8 4 R117H 2/226 (0.009) 0/576 (0) -29 10 4 I148T 3/224 (0.013) 0/576 (0) -29 C i 4 621+3 a/g 1/224 (0.004) 0/576 (0) -29 12 5 R170H 1/158 (0.006) 0/402 (0) -26 D i 6a 875+40 a/g 6/36 (0.167)c 0/118 (0)c -25 i 6b (ttga)6 13/36 (0.361) 1/118 (0.008) -23 E i 6b 1001+11 c/t 5/60 (0.083) 0/166 (0) -23 F i 8 1341+28 c/t 1/152 (0.007) 0/464 (0) -18 i 8 (tg)10 39/76 (0.513) 5/218 (0.023) -11 i 8 (tg)11 21/76 (0.276) 205/218 (0.940) -11 i 8 (tg)12 16/76 (0.211) 8/218 (0.037) -11 i 8 t5 4/76 (0.053) 2/218 (0.009) -11 i 8 t7 48/76 (0.632) 214/218 (0.982) -11 i 8 t9 24/76 (0.316) 2/218 (0.009) -11 16 10 M470V H ex 10 F508del 3/226 (0.013) 0/572 (0) 0 19 10 F508C 0/226 (0) 1/572 (0.002) 0 20 10 1716g/a 15/226 (0.066) 0/572 (0) 0 21 11 G542X 1/158 (0.006) 0/400 (0) +28 24 12 V562I 1/226 (0.004) 0/576 (0) +30 25 12 V562L 1/226 (0.004) 0/576 (0) +30 26 12 G576A 3/226 (0.013) 0/576 (0) +30 28 13 2082c/t 1/104 (0.010) 0/226 (0) +32 29 13 R668C 3/224 (0.013) 0/562 (0) +32 32 14a 2694t/g 45/70 (0.643) 9/208 (0.043) +35 I i 14a 2752-15 c/g 0/226 (0) 5/576 (0.009) +44 37 15 3030g/a 1/158 (0.006) 7/402 (0.017) +44 O i 15 3041-71 g/c 5/226 (0.022) 0/576 (0) +47 39 17a L997F 1/226 (0.004) 4/576 (0.007) +51 40 17a A1009T 0/226 (0) 1/572 (0.002) +51 42 17b F1052V 1/226 (0.004) 0/572 (0) +52 43 17b G1069R 1/226 (0.004) 0/572 (0) +52 44 17b Q1071H 1/226 (0.004) 0/572 (0) +52 45 17b 3417a/t 0/226 (0) 4/572 (0.007) +52 46 17b L1096R 1/226 (0.004) 0/572 (0) +52 52 19 3813a/g 0/118 (0) 1/484 (0.002) +68 53 19 S1235R 3/100 (0.030) 0/294 (0) +68 54 20 4002a/g 5/56 (0.089) 1/168 (0.006) +83 q in the M alleles q in the V alleles 56 21 4029a/g 0/194 (0) 3/506 (0.006) +93 57 21 N1303K 1/92 (0.011) 0/272 (0) +93 59 24 4404c/t 3/226 (0.013) 14/576 (0.024) +107 60 24 4521g/a 21/56 (0.375) 2/172 (0.012) +107 "slow evolution" markers "fast evolution" markers (i.e. STRs) H is the sum of the degrees of heterozygosity of all the markers Ref.No.a ABSOLUTE AND RELATIVE FREQUENCIES distance from the M470V siteb (Kb) H associated with the…. Login to comment

[hide] The role of cystic fibrosis transmembrane conducta... J Physiol. 2006 Apr 15;572(Pt 2):347-58. Epub 2006 Feb 16. Cui L, Aleksandrov L, Hou YX, Gentzsch M, Chen JH, Riordan JR, Aleksandrov AA
The role of cystic fibrosis transmembrane conductance regulator phenylalanine 508 side chain in ion channel gating.
J Physiol. 2006 Apr 15;572(Pt 2):347-58. Epub 2006 Feb 16., 2006-04-15 [PMID:16484308]

Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR) is an ion channel employing the ABC transporter structural motif. Deletion of a single residue (Phe508) in the first nucleotide-binding domain (NBD1), which occurs in most patients with cystic fibrosis, impairs both maturation and function of the protein. However, substitution of the Phe508 with small uncharged amino acids, including cysteine, is permissive for maturation. To explore the possible role of the phenylalanine aromatic side chain in channel gating we introduced a cysteine at this position in cysless CFTR, enabling its selective chemical modification by sulfhydryl reagents. Both cysless and wild-type CFTR ion channels have identical mean open times when activated by different nucleotide ligands. Moreover, both channels could be locked in an open state by introducing an ATPase inhibiting mutation (E1371S). However, the introduction of a single cysteine (F508C) prevented the cysless E1371S channel from maintaining the permanently open state, allowing closing to occur. Chemical modification of cysless E1371S/F508C by sulfhydryl reagents was used to probe the role of the side chain in ion channel function. Specifically, benzyl-methanethiosulphonate modification of this variant restored the gating behaviour to that of cysless E1371S containing the wild-type phenylalanine at position 508. This provides the first direct evidence that a specific interaction of the Phe508 aromatic side chain plays a role in determining the residency time in the closed state. Thus, despite the fact that this aromatic side chain is not essential for CFTR folding, it is important in the ion channel function.

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6 However, the introduction of a single cysteine (F508C) prevented the cysless E1371S channel from maintaining the permanently open state, allowing closing to occur. Login to comment
7 Chemical modification of cysless E1371S/F508C by sulfhydryl reagents was used to probe the role of the side chain in ion channel function. Login to comment
126 Influence of F508C substitution on channel gating With a functional cysless CFTR, it became possible to focus on a single cysteine introduced at position 508 which is known to be permissive for maturation of the protein (Du et al. 2005). Login to comment
127 However, as a prelude to this, we first examined the single-channel properties of a F508C Figure 4. Login to comment
132 With F508C in the cysless background there were even larger decreases in Po and increases in τc, with τo remaining unaltered (Fig. 5, second trace). Login to comment
134 This was indicated for cysless F508C in the lower two traces of Fig. 5 using the alternative ligands, dATP and 8BrATP, which resulted in the same increases in τo values relative to that with ATP as a ligand. Login to comment
135 Overall, the data in Fig. 5 revealed that the F508C substitution decelerated the gating of both wild-type and cysless CFTR primarily by prolonging the mean closed Table 1. Login to comment
136 Basic parameters of wild-type and mutant CFTR channels Type Ligand Po τo (ms) τc (ms) γ (pS) n Wild-type CFTR ATP 0.49 ± 0.03 220 ± 10 230 ± 10 12.3 ± 0.2 8 dATP 0.82 ± 0.03 420 ± 10 80 ± 10 12.3 ± 0.2 6 8BrATP 0.75 ± 0.02 510 ± 10 150 ± 10 12.3 ± 0.2 6 8N3ATP 0.58 ± 0.03 710 ± 10 560 ± 10 12.4 ± 0.2 5 F508C ATP 0.23 ± 0.03 230 ± 15 810 ± 10 12.3 ± 0.2 4 Cysless CFTR ATP 0.12 ± 0.03 220 ± 15 1800 ± 120 13.5 ± 0.2 7 dATP 0.21 ± 0.03 410 ± 15 1600 ± 100 13.4 ± 0.2 4 8BrATP 0.24 ± 0.02 520 ± 15 1680 ± 120 13.2 ± 0.2 5 8N3ATP 0.26 ± 0.03 715 ± 15 2100 ± 160 13.4 ± 0.2 3 Cysless F508C ATP 0.04 ± 0.02 210 ± 20 5000 ± 850 13.4 ± 0.2 5 dATP 0.07 ± 0.02 415 ± 20 5200 ± 720 13.5 ± 0.2 3 8BrATP 0.09 ± 0.03 520 ± 20 5600 ± 900 13.5 ± 0.2 3 CFTR, cystic fibrosis transmembrane conductance regulator. Login to comment
139 For cysless F508C, the effective values of τc were estimated as τo(1 - Po)/Po. time. Login to comment
140 While informative, this large prolongation in cysless F508C limits detailed analysis of its gating kinetics. Login to comment
145 The fact that the essentially non-hydrolytic cysless E1371S channel was able to open and close in a robust mannerisofinterestmechanistically.However,ofpractical importance for the utility of the cysless protein to study the role of the Phe508 residue in gating was the fact that the E1371S substitution also increased the activity of cysless F508C (Fig. 6, lower panel, Po = 0.25 ± 0.03, n = 4). Login to comment
146 Moreover, it was possible to differentiate better between cysless E1371S and cysless E1371S/F508C by using 8BrATP instead of ATP as a ligand (Fig. 7, first panel, Po = 0.97 ± 0.02, n = 4 and second panel (Fig. 7, second panel, Po = 0.71 ± 0.03, n = 4). Login to comment
154 This was found to be the case as the positively charged MTSET not only did not lock the cysless E1371S/F508C channel open but completely ablated gating (Fig. 7, lower trace, Po < 0.01, n = 3). Login to comment
163 Influence of F508C on CFTR channel gating Typical records of F508C and cysless F508C single-channel activity driven by different ligands at 30◦C are shown in the middle of each panel. Login to comment
165 Mean closed time for cysless F508C driven by different ligands was roughly estimated as τc = τo(1 - P o)/P o. Login to comment
181 The cysless E1371S single-channel record is shown in the middle panel. The influence of the further introduction of F508C in the cysless E1371S background on the ion channel gating is shown in the lower panel. The mean values of Po ± S.E.M. and number of experiments are shown in the text. All records were done at 30◦C and 2 mM ATP. Login to comment
183 That is why our experiments with the F508C mutation and its chemical modification were done on this particular background. Login to comment
197 Effect of the introduction of F508C in the cysless E1371S background on the ion channel gating is shown in the second panel. The result of the chemical modification of the cysless E1371S/F508C channel by MTSBn at the cis side on the ion channel gating is shown by the arrow in the third panel. The effect of positively charged 2-trimethylammonioethylmethanethiosulphonate (MTSET) on the cysless E1371S/F508C ion channel function is shown by the arrow in the lower panel. The values of Po before and after chemical modification are shown above the traces. Login to comment
200 Although the F508C variant appeared to mature similarly as wild-type and mediated iodide efflux (Du et al. 2005), we show that at the single-channel level it greatly increased the channelmeanclosedtimeinboththewild-typeandcysless background, suggesting that the phenylalanine side chain plays a role in channel gating. Login to comment
201 This could be confirmed using a site II ATPase-inhibited mutant (E1371S) which is locked open in both the wild-type and cysless backgrounds, while the F508C version of cysless E1371S was unable to maintain the locked open state. Login to comment
202 Neither total cysteine removal, nor F508C substitution, affects open state. Login to comment
207 The ability of F508C version of cysless E1371S to maintain the locked open state was fully restored on modificaton of Cys508 with MTSBn. Login to comment
212 Thus, just as removal of all endogenous cysteines apparently alters the gating response to ATP binding rather than binding itself, this also appears to be the case for the further increment in mean closed time caused by F508C. Login to comment

[hide] Analysis of Y chromosome microdeletions and CFTR g... Vojnosanit Pregl. 2007 Apr;64(4):253-6. Dinic J, Kusic J, Nikolic A, Divac A, Ristanovic M, Radojkovic D
Analysis of Y chromosome microdeletions and CFTR gene mutations as genetic markers of infertility in Serbian men.
Vojnosanit Pregl. 2007 Apr;64(4):253-6., [PMID:17580535]

Abstract [show]
BACKGROUND/AIM: Impaired fertility of a male partner is the main cause of infertility in up to one half of all infertile couples. At the genetic level, male infertility can be caused by chromosome aberrations or gene mutations. The presence and types of Y chromosome microdeletions and cystic fybrosis transmembrane conductance regulator (CFTR) gene mutations as genetic cause of male infertility was tested in Serbian men. The aim of this study was to analyze CFTR gene mutations and Y chromosome microdelations as potential causes of male infertility in Serbian patients, as well as to test the hypothesis that CFTR mutations in infertile men are predominantly located in the several last exons of the gene. METHODS: This study has encompassed 33 men with oligo- or azoospermia. The screening for Y chromosome microdeletions in the azoospermia factor (AZF) region was performed by multiplex PCR analysis. The screening of the CFTR gene was performed by denaturing gradient gel electrophoresis (DGGE) method. RESULTS: Deletions on Y chromosome were detected in four patients, predominantly in AZFc region (four of total six deletions). Mutations in the CFTR gene were detected on eight out of 66 analyzed chromosomes of infertile men. The most common mutation was F508del (six of total eight mutations). CONCLUSION: This study confirmed that both Y chromosome microdeletions and CFTR gene mutations played important role in etiology of male infertility in Serbian infertile men. Genetic testing for Y chromosome microdeletions and CFTR gene mutations has been introduced in routine daignostics and offered to couples undergoing assisted reproduction techniques. Considering that both the type of Y chromosome microdeletion and the type of CFTR mutation have a prognostic value, it is recomended that AZF and CFTR genotyping should not only be performed in patients with reduced sperm quality before undergoing assisted reproduction, but also for the purpose of preimplantation and prenatal diagnostics in couples in which in vitro fertilization has been performed successfully.

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62 Common polymorphisms F508C, 2694T/G, 4002A/G and 4029A/G were detected in several patients in each of the three groups. Login to comment

[hide] Phenylalanine-508 mediates a cytoplasmic-membrane ... Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3256-61. Epub 2008 Feb 27. Serohijos AW, Hegedus T, Aleksandrov AA, He L, Cui L, Dokholyan NV, Riordan JR
Phenylalanine-508 mediates a cytoplasmic-membrane domain contact in the CFTR 3D structure crucial to assembly and channel function.
Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3256-61. Epub 2008 Feb 27., 2008-03-04 [PMID:18305154]

Abstract [show]
Deletion of phenylalanine-508 (Phe-508) from the N-terminal nucleotide-binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ATP-binding cassette (ABC) transporter family, disrupts both its folding and function and causes most cystic fibrosis. Most mutant nascent chains do not pass quality control in the ER, and those that do remain thermally unstable, only partially functional, and are rapidly endocytosed and degraded. Although the lack of the Phe-508 peptide backbone diminishes the NBD1 folding yield, the absence of the aromatic side chain is primarily responsible for defective CFTR assembly and channel gating. However, the site of interdomain contact by the side chain is unknown as is the high-resolution 3D structure of the complete protein. Here we present a 3D structure of CFTR, constructed by molecular modeling and supported biochemically, in which Phe-508 mediates a tertiary interaction between the surface of NBD1 and a cytoplasmic loop (CL4) in the C-terminal membrane-spanning domain (MSD2). This crucial cytoplasmic membrane interface, which is dynamically involved in regulation of channel gating, explains the known sensitivity of CFTR assembly to many disease-associated mutations in CL4 as well as NBD1 and provides a sharply focused target for small molecules to treat CF. In addition to identifying a key intramolecular site to be repaired therapeutically, our findings advance understanding of CFTR structure and function and provide a platform for focused biochemical studies of other features of this unique ABC ion channel.

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71 Cross-linking of Cys pairs F508C/L1065C, F508C/F1068C, F508C/G1069C, and F508C/F1074C confirms that Phe-508 in NBD1 associates with CL4 in MSD2 (Fig. 3 and SI Fig. 7). Login to comment
84 Nevertheless, the proximity or relative orientation of the F508C/F1068C, F508C/G1069C, and V510C/G1069C pairs permitted very little disulfide bond formation on oxidation catalyzed by copper phenanthroline, i.e., only a very small proportion of mature band was converted to cross-linked band Fig. 2. Login to comment
131 (Bottom) Cys-less CFTR with F508C/F1068C (n ϭ 4). 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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55 For example, true homozygous I507del (c.1519_1521delATC, p.Ile507del) must be distinguished from heterozygous I507del (c.1519_1521delATC, p.Ile507del) with F508C (c.1522T4G, p.Phe508Cys) in trans. Login to comment

[hide] Snapback primer genotyping with saturating DNA dye... Clin Chem. 2008 Oct;54(10):1648-56. Epub 2008 Aug 1. Zhou L, Errigo RJ, Lu H, Poritz MA, Seipp MT, Wittwer CT
Snapback primer genotyping with saturating DNA dye and melting analysis.
Clin Chem. 2008 Oct;54(10):1648-56. Epub 2008 Aug 1., [PMID:18676584]

Abstract [show]
BACKGROUND: DNA hairpins have been used in molecular analysis of PCR products as self-probing amplicons. Either physical separation or fluorescent oligonucleotides with covalent modifications were previously necessary. METHODS: We performed asymmetric PCR for 40-45 cycles in the presence of the saturating DNA dye, LCGreen Plus, with 1 primer including a 5' tail complementary to its extension product, but without any special covalent modifications. Samples were amplified either on a carousel LightCycler for speed or on a 96/384 block cycler for throughput. In addition to full-length amplicon duplexes, single-stranded hairpins were formed by the primer tail "snapping back" and hybridizing to its extension product. High-resolution melting was performed on a HR-1 (for capillaries) or a LightScanner (for plates). RESULTS: PCR products amplified with a snapback primer showed both hairpin melting at lower temperature and full-length amplicon melting at higher temperature. The hairpin melting temperature was linearly related to the stem length (6-28 bp) and inversely related to the log of the loop size (17-135 bases). We easily genotyped heterozygous and homozygous variants within the stem, and 100 blinded clinical samples previously typed for F5 1691G>A (Leiden) were completely concordant by snapback genotyping. We distinguished 7 genotypes in 2 regions of CFTR exon 10 with symmetric PCR using 2 snapback primers followed by product dilution to favor intramolecular hybridization. CONCLUSIONS: Snapback primer genotyping with saturating dyes provides the specificity of a probe with only 2 primers that are free of special covalent labels in a closed-tube system.

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193 Snapback 1 covered the F508del, I507del, F508C, and I506V variants with melting transitions between 46 and 60 °C. Login to comment
196 Samples included wild type (circles), compound F508del/Q493X heterozygote (connected small diamonds), I506V heterozygote (small diamonds), F508C heterozygote (small squares), I507del heterozygote (large squares), F508del heterozygote (connected large diamonds), and F508del homozygote (connected squares). Login to comment

[hide] Best practice guidelines for molecular genetic dia... Eur J Hum Genet. 2009 Jan;17(1):51-65. Epub 2008 Aug 6. Dequeker E, Stuhrmann M, Morris MA, Casals T, Castellani C, Claustres M, Cuppens H, des Georges M, Ferec C, Macek M, Pignatti PF, Scheffer H, Schwartz M, Witt M, Schwarz M, Girodon E
Best practice guidelines for molecular genetic diagnosis of cystic fibrosis and CFTR-related disorders--updated European recommendations.
Eur J Hum Genet. 2009 Jan;17(1):51-65. Epub 2008 Aug 6., [PMID:18685558]

Abstract [show]
The increasing number of laboratories offering molecular genetic analysis of the CFTR gene and the growing use of commercial kits strengthen the need for an update of previous best practice guidelines (published in 2000). The importance of organizing regional or national laboratory networks, to provide both primary and comprehensive CFTR mutation screening, is stressed. Current guidelines focus on strategies for dealing with increasingly complex situations of CFTR testing. Diagnostic flow charts now include testing in CFTR-related disorders and in fetal bowel anomalies. Emphasis is also placed on the need to consider ethnic or geographic origins of patients and individuals, on basic principles of risk calculation and on the importance of providing accurate laboratory reports. Finally, classification of CFTR mutations is reviewed, with regard to their relevance to pathogenicity and to genetic counselling.

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144 A (T)5 variant can either be associated with (TG)11, (TG)12, (TG)13, and rarely (TG)15 repeats.74 When (T)5 is found in diagnostic testing, for example, for CBAVD or atypical presentation, determination of Table 4 Classification of CFTR mutations with regard to their potential for causing disease Mutation group Examples CF-causing F508del Mainly nonsense, frameshift, splicing (invariant dinucleotide): G542X, R553X, W1282X, 2183AA4G, 3659delC, 1717-1G4A, 3120+1G4A Missense that severely affects CFTR synthesis or function: G551D, N1303K, R347P 2789+5G4A, 3849+10kbC4T, 3272-26A4G, L206Wa , D1152Ha , (TG)13(T)5a CFTR-related disorders associated L206Wa , D1152Ha , (TG)13(T)5a [R117H;(T)7], (TG)12(T)5, L997F, V562I, [R668C;G576A;D443Y], [R74W;D1270N] (TG)11(T)5b , S1235Rb No clinical consequences 875+40A4G, M470V (1540A4G), I506V (1648A4G), F508C (1655T4G), 1716G4A, 2694T4G, 4002A4G, 2752-15G4C (TG)11(T)5b , S1235Rb Unproven or uncertain clinical relevance Mainly missense mutations G622D, R170H, V938G, I125T Putative splice mutations: 406-6T4C, 2752-26A4G, 3601-17T4C Only a fraction of mutations and patients have been characterized in detail and, with the exception of frequent mutations, only small numbers of patients have been available for the study of most mutations. Login to comment

[hide] A novel computational and structural analysis of n... Genomic Med. 2008 Jan;2(1-2):23-32. Epub 2008 May 14. George Priya Doss C, Rajasekaran R, Sudandiradoss C, Ramanathan K, Purohit R, Sethumadhavan R
A novel computational and structural analysis of nsSNPs in CFTR gene.
Genomic Med. 2008 Jan;2(1-2):23-32. Epub 2008 May 14., [PMID:18716917]

Abstract [show]
Single Nucleotide Polymorphisms (SNPs) are being intensively studied to understand the biological basis of complex traits and diseases. The Genetics of human phenotype variation could be understood by knowing the functions of SNPs. In this study using computational methods, we analyzed the genetic variations that can alter the expression and function of the CFTR gene responsible candidate for causing cystic fibrosis. We applied an evolutionary perspective to screen the SNPs using a sequence homology-based SIFT tool, which suggested that 17 nsSNPs (44%) were found to be deleterious. The structure-based approach PolyPhen server suggested that 26 nsSNPS (66%) may disrupt protein function and structure. The PupaSuite tool predicted the phenotypic effect of SNPs on the structure and function of the affected protein. Structure analysis was carried out with the major mutation that occurred in the native protein coded by CFTR gene, and which is at amino acid position F508C for nsSNP with id (rs1800093). The amino acid residues in the native and mutant modeled protein were further analyzed for solvent accessibility, secondary structure and stabilizing residues to check the stability of the proteins. The SNPs were further subjected to iHAP analysis to identify htSNPs, and we report potential candidates for future studies on CFTR mutations.

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6 Structure analysis was carried out with the major mutation that occurred in the native protein coded by CFTR gene, and which is at amino acid position F508C for nsSNP with id (rs1800093). Login to comment
114 The nsSNP with an id (rs1800093) showed a SIFT tolerance index of 0.00 and PSIC score difference 3.0 at position F508C and was selected for modeling analysis. Login to comment
125 The nsSNPs which were predicted to be Table 1 List of nsSNPs that were predicted to be deleterious by SIFT and PolyPhen SNPs ID Alleles AA change Tolerance index PSIC rs1800072 G/A V11C 1.00 0.150 rs1800073 C/T R31C 0.18 2.288 rs1800074 A/T D44V 0.01 2.532 rs1800076 G/A R75Q 0.03 1.754 rs1800078 T/C L138P 0.01 2.192 rs35516286 T/C I148T 0.41 1.743 rs1800079 G/A R170H 0.05 1.968 rs1800080 A/G S182G 0.03 1.699 rs1800086 C/G T351S 0.30 1.600 rs1800087 A/C Q353H 0.03 2.093 rs4727853 C/A N417K 1.00 0.015 rs11531593 C/A F433L 0.65 0.694 rs1800089 C/T L467F 0.15 1.568 rs213950 G/A V470M 0.17 1.432 rs1800092 C/A/G I506M 0.00 1.574 rs1801178 A/G I507V 0.38 0.314 rs1800093 T/G F508C 0.00 3.031 rs35032490 A/G K532E 1.00 1.525 rs1800097 G/A V562I 0.13 0.345 rs41290377 G/C G576A 0.33 1.262 rs766874 C/T S605F 0.03 2.147 rs1800099 A/G S654G 0.03 1.611 rs1800100 C/T R668C 0.01 2.654 rs1800101 T/C F693L 0.61 0.895 rs1800103 A/G I807M 0.01 1.554 rs1800106 T/C Y903H 0.52 0.183 rs1800107 G/T S909I 0.10 1.624 rs1800110 T/C L967S 0.07 1.683 rs1800111 G/C L997F 0.24 1.000 rs1800112 T/C I1027T 0.03 1.860 rs1800114 C/T A1067V 0.04 1.542 rs36210737 T/A M1101K 0.05 2.637 rs35813506 G/A R1102K 0.52 1.589 rs1800120 G/T R1162L 0.00 2.038 rs1800123 C/T T1220I 0.22 0.059 rs34911792 T/G S1235R 0.45 1.483 rs11971167 G/A D1270N 0.12 1.739 rs4148725 C/T R1453W 0.00 2.513 Highly deleterious by SIFT and damaging by PolyPhen are indicated as bold deleterious in causing an effect in the structure and function of the protein by SIFT, PolyPhen and Pupasuite correlated well with experimental studies (Tsui 1992; Ghanem et al. 1994; Bienvenu et al. 1998) (Table 3). Login to comment
135 According to this, the mutation occurred for native protein (1nbd) at position F508C with an SNP id namely (rs1800093), based on SIFT and PolyPhen results. Login to comment
138 It can be seen that total energy for the native (1nbd) and mutant type structure F508C were found to be - 9786.37 and -9902.49 Kcal/mol respectively. Login to comment
140 The superimposed structures of the native (1nbd) with mutant type protein F508C are shown in Figs. Login to comment
144 It is interesting to note that the residues Ser (434), Tyr (512) and Ser (557) showed a change in solvent accessibility from a buried to exposed state and Ala (566) from an exposed to buried state in the mutant protein F508C. Login to comment
157 Interestingly, on mutation at position F508C two residues, namely Leu (453) and Cys (491), in the native protein were replaced with the residues Glu (542) and Gly (543), respectively. Login to comment
177 We mapped the deleterious mutation for (1nbd) at position F508C with an SNP id (rs1800093) based on SIFT and PolyPhen results. Login to comment
178 Structural significance of native and mutant models of the CFTR gene at position F508C were further investigated in this work by solvent accessibility, secondary structure analysis and stabilizing residues. Login to comment

[hide] Novel cause of hereditary obstructive azoospermia:... Reprod Biomed Online. 2009 Mar;18(3):327-32. Radpour R, Taherzadeh-Fard E, Gourabi H, Aslani S, Vosough Dizaj A, Aslani A
Novel cause of hereditary obstructive azoospermia: a T2 allele in the CFTR gene.
Reprod Biomed Online. 2009 Mar;18(3):327-32., [PMID:19298730]

Abstract [show]
Congenital bilateral absence of the vas deferens (CBAVD) is a frequent cause of obstructive azoospermia, and caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. A novel TG(13)T(2) allele was identified in a CBAVD patient with no clinical cystic fibrosis phenotype, normal pancreatic function, normal sweat chloride concentrations and no Y chromosome microdeletions. This case was studied for CFTR mutations, IVS8-poly(T), and M470V exon 10 missense polymorphism. One novel allele was detected in the (TG)(m)(T)(n) loci that had not been reported previously. This patient carried a [TG(11)T(9); R117H; p.Met470Val] haplotype on the other chromosome. Since the TG(13)T(2) allele was a compound heterozygote with R117H mutation, it was difficult to judge the severity of this allele. To better understand the complex regulation of exon 9 splicing, the levels of correctly spliced CFTR transcripts in CFTR-expressing epithelial cells derived from vas deferens and epididymis were analysed. These data emphasize the role of the T2 allele in CBAVD, and identify the T2 allele as a severe CBAVD disease-causing mutation. According to the data, the longer (TG)(m) polymorphic tract increases the proportion of transcripts with exon 9 deletion (9-), but only when activated by the short T allele.

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97 Previously one group in France were able to detect a novel T3 allele (TG12 T3 ) in a CBAVD patient who carried a [TG11 T7 ; p.Phe508Cys; p.Met470Val] haplotype on the other chromosome (Disset et al., 2005). Login to comment

[hide] A novel approach to CFTR mutation testing by pyros... Clin Chem. 2009 Jun;55(6):1083-91. Epub 2009 Apr 16. Bickmann JK, Kamin W, Wiebel M, Hauser F, Wenzel JJ, Neukirch C, Stuhrmann M, Lackner KJ, Rossmann H
A novel approach to CFTR mutation testing by pyrosequencing-based assay panels adapted to ethnicities.
Clin Chem. 2009 Jun;55(6):1083-91. Epub 2009 Apr 16., [PMID:19372188]

Abstract [show]
BACKGROUND: Cystic fibrosis (CF) is a common autosomal recessive genetic disorder caused by a variety of sequence alterations in the CFTR gene [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)]. Because the relative prevalence of mutations strongly depends on the ethnic background, first-level testing of CF as defined by recent consensus recommendations ought to be adaptable to the ethnicity of patients. METHODS: We therefore developed and implemented a diagnostic approach to first-level testing for CF based on published mutation frequencies and Pyrosequencing (PSQ) technology that we complemented with standard procedures of mutation detection at the second level. RESULTS: The current test system of PSQ assays for 46 target CF mutations [including CFTRdele2,3 (21 kb) and 1342-6 (T)(n) (5T/7T/9T)] permits recombinations of single assays to optimize sensitivities for certain ethnicities. By easy expansion of the original mutation panel, the first-level test sensitivities with other ethnic groups would be increased, provided that the mutation frequencies are known. The test was validated with our local, ethnically mixed, but mainly German population (155 patients). The mutation-detection rate for the 92 patients whose CF was confirmed by the sweat test was 89.0% for the patients of German descent (73 of the 92 patients) and 73.7% for the patients of any other origin (19 of the 92 patients). Ethnicity-adapted testing panels for our foreign CF patients would increase the sensitivities for the respective groups by approximately 5%. CONCLUSIONS: PSQ-based genotyping is a reliable, convenient, highly flexible, and inexpensive alternative to conventional methods for first-level testing of CFTR, facilitating flexible adaptation of the analyzed mutation panel to any local ethnic group.

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129 Furthermore, the PSQ-based first-level test avoids common pitfalls, as do the most recent assays: It correctly discriminates G551D and R553X, as well as I507del and F508del (Fig. 3; see Fig. 1 in the online Data Supplement), thus obviating reflex testing for benign sequence variations such as I506V, I507V, and F508C. Login to comment
148 Fig. 2 in the online Data Supplement illustrates the capability of the assay to discriminate I507del, F508del, 1677delTA, and the interfering benign variants I506V, I507V, and F508C. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... Cancer. 2010 Jan 1;116(1):203-9. McWilliams RR, Petersen GM, Rabe KG, Holtegaard LM, Lynch PJ, Bishop MD, Highsmith WE Jr
Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations and risk for pancreatic adenocarcinoma.
Cancer. 2010 Jan 1;116(1):203-9., 2010-01-01 [PMID:19885835]

Abstract [show]
BACKGROUND: Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are common in white persons and are associated with pancreatic disease. The purpose of this case-control study was to determine whether CFTR mutations confer a higher risk of pancreatic cancer. METHODS: In a case-control study, the authors compared the rates of 39 common cystic fibrosis-associated CFTR mutations between 949 white patients with pancreatic adenocarcinoma and 13,340 white controls from a clinical laboratory database for prenatal testing for CFTR mutations. The main outcome measure was the CFTR mutation frequency in patients and controls. RESULTS: Overall, 50 (5.3%) of 949 patients with pancreatic cancer carried a common CFTR mutation versus 510 (3.8%) of 13,340 controls (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.04-1.89; P = .027). Among patients who were younger when their disease was diagnosed (<60 years), the carrier frequency was higher than in controls (OR, 1.82; 95% CI, 1.14-2.94; P = .011). In patient-only analyses, the presence of a mutation was associated with younger age (median 62 vs 67 years; P = .034). In subgroups, the difference was seen only among ever-smokers (60 vs 65 years, P = .028). Subsequent sequencing analysis of the CFTR gene detected 8 (16%) compound heterozygotes among the 50 patients initially detected to have 1 mutation. CONCLUSIONS: Carrying a disease-associated mutation in CFTR is associated with a modest increase in risk for pancreatic cancer. Those affected appear to be diagnosed at a younger age, especially among smokers. Clinical evidence of antecedent pancreatitis was uncommon among both carriers and noncarriers of CFTR mutations.

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85 * Mutations recommended for screening by the American College of Medical Genetics.16 Mutations not listed but included in the 39-site assay: 3120þ1G>A, R334W, 3569delC, 1078delT, S549N, 3876delA, 1898þ5G>T, 2307insA, Y1092X, M1101K, S1255X, Y122X, A559T; in the 33-site assay: 3120þ1G>A, R334W, 3569delC, S549N, 3876delA, F508C. Login to comment

[hide] Clinical and genetic characteristics of meconium i... J Pediatr Gastroenterol Nutr. 2010 May;50(5):569-72. Gorter RR, Karimi A, Sleeboom C, Kneepkens CM, Heij HA
Clinical and genetic characteristics of meconium ileus in newborns with and without cystic fibrosis.
J Pediatr Gastroenterol Nutr. 2010 May;50(5):569-72., [PMID:20386322]

Abstract [show]
The present study compares the clinical presentation and diagnostic features of meconium ileus (MI) in newborns with and without cystic fibrosis (CF). A retrospective study of 43 patients treated in the Pediatric Surgical Center of Amsterdam was performed. Twenty-three of the patients (53.5%) were diagnosed as having CF. Complex MI was significantly more frequent in patients without CF, and these patients had lower gestational ages and birth weights than patients with CF. All of the patients with complex MI had homozygous DF508 mutations, whereas the patients with simple MI also had other mutations. None of the patients with other mutations had complex MI. Therefore, we conclude that the clinical entity of MI represents a spectrum of underlying pathologies.

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25 The mutations tested for include the most common mutations DF508, F508C, G542X, R553X, N1303K, R1162X, and E60X, which represent 94% to 98% of the known mutations in the CFTR gene and are found in more than 99% of the Dutch population with CF. 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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184 I506V, I507V, and F508C are performed only as reflex tests for unexpected homozygosity for ⌬F508 and/or ⌬I507. Login to comment

[hide] An update on cystic fibrosis screening. Clin Lab Med. 2010 Sep;30(3):533-43. Goetzinger KR, Cahill AG
An update on cystic fibrosis screening.
Clin Lab Med. 2010 Sep;30(3):533-43., [PMID:20638569]

Abstract [show]
Cystic fibrosis (CF) is a monogenic, autosomal recessive disorder, which ultimately leads to multisystem organ dysfunction and a subsequent decrease in life expectancy. Because of the sizeable number of disease causing mutations (>1000) and expansive ethnic and racial distribution, CF has presented a challenge for prenatal diagnosis. This article aims to review the genetics of CF, its spectrum of genotypic-phenotypic variations, current prenatal carrier screening and diagnostic recommendations, ultrasonographic markers of CF, and available reproductive options for carrier couples.

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53 Given that 5% of the general population will test positive for the 5T polymorphism alone, this test is recommended only as a reflex to a positive R117H result.22,23 Non CF-causing variants, including I506V, I507V, and F508C, can mistakenly cause a false-positive result based on laboratory and testing methodologies. Login to comment
54 For example, in patients who screen positive for DF508 carrier status and for one of the aforementioned mutations, a false-positive test for DF508 homozygosity may be obtained, although the patient is an otherwise healthy individual.22 Although F508C has been associated with CBAVD, neither I506V nor I507V have been associated with any phenotypic manifestations of classical CF or CBAVD.24 Therefore, reflex testing for I506V, I507V, and F508C should be performed in any healthy individual who tests positive for DF508 or DI507 homozygosity, but these mutations should not be otherwise used for a priori testing. Login to comment

[hide] The cystic fibrosis-causing mutation deltaF508 aff... J Biol Chem. 2010 Nov 12;285(46):35825-35. Epub 2010 Jul 28. Thibodeau PH, Richardson JM 3rd, Wang W, Millen L, Watson J, Mendoza JL, Du K, Fischman S, Senderowitz H, Lukacs GL, Kirk K, Thomas PJ
The cystic fibrosis-causing mutation deltaF508 affects multiple steps in cystic fibrosis transmembrane conductance regulator biogenesis.
J Biol Chem. 2010 Nov 12;285(46):35825-35. Epub 2010 Jul 28., 2010-11-12 [PMID:20667826]

Abstract [show]
The deletion of phenylalanine 508 in the first nucleotide binding domain of the cystic fibrosis transmembrane conductance regulator is directly associated with >90% of cystic fibrosis cases. This mutant protein fails to traffic out of the endoplasmic reticulum and is subsequently degraded by the proteasome. The effects of this mutation may be partially reversed by the application of exogenous osmolytes, expression at low temperature, and the introduction of second site suppressor mutations. However, the specific steps of folding and assembly of full-length cystic fibrosis transmembrane conductance regulator (CFTR) directly altered by the disease-causing mutation are unclear. To elucidate the effects of the DeltaF508 mutation, on various steps in CFTR folding, a series of misfolding and suppressor mutations in the nucleotide binding and transmembrane domains were evaluated for effects on the folding and maturation of the protein. The results indicate that the isolated NBD1 responds to both the DeltaF508 mutation and intradomain suppressors of this mutation. In addition, identification of a novel second site suppressor of the defect within the second transmembrane domain suggests that DeltaF508 also effects interdomain interactions critical for later steps in the biosynthesis of CFTR.

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115 Consistent with this result, the introduction of the -3M mutations onto F508A and F508C had little effect on protein maturation. Login to comment

[hide] A new complex allele of the CFTR gene partially ex... Genet Med. 2010 Sep;12(9):548-55. Lucarelli M, Narzi L, Pierandrei S, Bruno SM, Stamato A, d'Avanzo M, Strom R, Quattrucci S
A new complex allele of the CFTR gene partially explains the variable phenotype of the L997F mutation.
Genet Med. 2010 Sep;12(9):548-55., [PMID:20706124]

Abstract [show]
PURPOSE: To evaluate the role of complex alleles, with two or more mutations in cis position, of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in the definition of the genotype-phenotype relationship in cystic fibrosis (CF), and to evaluate the functional significance of the highly controversial L997F CFTR mutation. METHODS: We evaluated the diagnosis of CF or CFTR-related disorders in 12 unrelated subjects with highly variable phenotypes. According to a first CFTR mutational analysis, subjects appeared to be compound heterozygotes for a classic mutation and the L997F mutation. A further CFTR mutational analysis was conducted by means of a protocol of extended sequencing, particularly suited to the detection of complex alleles. RESULTS: We detected a new [R117L; L997F] CFTR complex allele in the four subjects with the highest sweat test values and CF. The eight subjects without the complex allele showed the most varied biochemical and clinical outcome and were diagnosed as having mild CF, CFTR-related disorders, or even no disease. CONCLUSIONS: The new complex allele partially explains the variable phenotype in CF subjects with the L997F mutation. CFTR complex alleles are likely to have a role in the definition of the genotype-phenotype relationship in CF. Whenever apparently identical CFTR-mutated genotypes are found in subjects with divergent phenotypes, an extensive mutational search is mandatory.

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103 In vivo findings and, in some cases, in vitro functional characterizations have been reported for [F508C; S1251N],38 [R347H; D979A],39,40 [R74W; D1270N],41 [G628R; S1235R],42,43 [M470V; S1235R],42 [S912L; G1244V],44 [R117H; (TG)mTn],45-47 [R117C; (TG)mTn],46 [S1235R; (TG)mT5],48 [G576A; R668C],10,49 [V562I; A1006E],49 [R352W; P750L],49 [1198_1203del TGGGCT; 1204GϾA],49 [V754M; CFTRdele3_10,14b_16],50 and [F508del; I1027T].51 These complex alleles have been found in patients with either CF or CFTR-RD, although more often in the former. Login to comment
105 Both in vivo and in vitro studies have also highlighted cases in which there is one main mutation with the phenotypical effect that is worsened by a second mutation, which may even be a neutral variant when isolated, as occurs for F508C,38 R74W,41 S912L,44 and M470V.42 However, different effects have also been described, as in the case of the two M470 and R1235 variants, which give rise to a hyperactive CFTR when present on different alleles but have a suppressive effect when combined on the same allele.42 In addition, the finding of complex alleles in CFTR-RD seems to suggest that a second CFTR mutation may even lead to a partial reversion of the phenotype.43 Indeed, in a reduced number of complex alleles, the effect of the second mutation may partially correct the functional defect, thereby lessening the phenotypical effect, as has been demonstrated for the R553Q mutation in the [F508del; R553Q] complex allele by in vivo52 and in vitro53 studies and for the R553M mutation in the [F508del; R553M] complex allele by an in vitro study.53 A milder phenotypical effect has also been demonstrated for the [R334W; R1158X]54 and [-102T; S549R(TϾG)]55 complex alleles if compared with alleles carrying, respectively, isolated R1158X or S549R(TϾG). Login to comment

[hide] Combined bicarbonate conductance-impairing variant... Gastroenterology. 2011 Jan;140(1):162-71. Epub 2010 Oct 25. Schneider A, Larusch J, Sun X, Aloe A, Lamb J, Hawes R, Cotton P, Brand RE, Anderson MA, Money ME, Banks PA, Lewis MD, Baillie J, Sherman S, Disario J, Burton FR, Gardner TB, Amann ST, Gelrud A, George R, Rockacy MJ, Kassabian S, Martinson J, Slivka A, Yadav D, Oruc N, Barmada MM, Frizzell R, Whitcomb DC
Combined bicarbonate conductance-impairing variants in CFTR and SPINK1 variants are associated with chronic pancreatitis in patients without cystic fibrosis.
Gastroenterology. 2011 Jan;140(1):162-71. Epub 2010 Oct 25., [PMID:20977904]

Abstract [show]
BACKGROUND & AIMS: Idiopathic chronic pancreatitis (ICP) is a complex inflammatory disorder associated with multiple genetic and environmental factors. In individuals without cystic fibrosis (CF), variants of CFTR that inhibit bicarbonate conductance but maintain chloride conductance might selectively impair secretion of pancreatic juice, leading to trypsin activation and pancreatitis. We investigated whether sequence variants in the gene encoding the pancreatic secretory trypsin inhibitor SPINK1 further increase the risk of pancreatitis in these patients. METHODS: We screened patients and controls for variants in SPINK1 associated with risk of chronic pancreatitis and in all 27 exons of CFTR. The final study group included 53 patients with sporadic ICP, 27 probands with familial ICP, 150 unrelated controls, 375 additional controls for limited genotyping. CFTR wild-type and p.R75Q were cloned and expressed in HEK293 cells, and relative conductances of HCO(3)(-) and Cl(-) were measured. RESULTS: SPINK1 variants were identified in 36% of subjects and 3% of controls (odds ratio [OR], 18.1). One variant of CFTR not associated with CF, p.R75Q, was found in 16% of subjects and 5.3% of controls (OR, 3.4). Coinheritance of CFTR p.R75Q and SPINK1 variants occurred in 8.75% of patients and 0.38% of controls (OR, 25.1). Patch-clamp recordings of cells that expressed CFTR p.R75Q showed normal chloride currents but significantly reduced bicarbonate currents (P = .0001). CONCLUSIONS: The CFTR variant p.R75Q causes a selective defect in bicarbonate conductance and increases risk of pancreatitis. Coinheritance of p.R75Q or CF causing CFTR variants with SPINK1 variants significantly increases the risk of ICP.

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99 Total CFTR Sequencing Results of Patients With SPINK1 Mutations Diagnosis Age at diagnosis (y) CFTR mutations SPINK1 mutations 1 SP 12 -/- N34S/P55S 2 SP 46 -/- N34S/P55S 3 SP 13 -/- N34S/N34S 4 FP Infant -/- N34S/N34S 5 FP 8 R560T/- N34S/P55S 6 FP 15 M952T/- N34S/N34S 7 SP 19 R75Q/-a N34S/N34S 8 SP 3 F508del/-a P55S/- 9 SP 3 F508del/1584GtoAa N34S/- 10 SP 19 F508del/-a N34S/- 11 FP 12 F508del/I807M, 3139ϩ42AtoTa N34S/- 12 SP 14 D443YϩG576AϩR668Cb N34S/- 13 SP 1 F508C/-a N34S/- 14 SP 20 IVS8-T5-TG12/-a N34S/- 15 SP 16 R75Q/-a P55S/- 16 SP 9 R75Q/-a N34S/- 17 SP 9 R75Q/-a N34S/- 18 SP 16 R75Q/ϩ1584GtoAa N34S/- 19 FP 7 R75Q/-a N34S/- 20 FP 35 R75Q/-a N34S/- 21 FP 2 1584GtoA/-a N34S/- 22 FP Child 1584GtoA/-a N34S/- 23 SP 14 1584GtoA/-a N34S/- 24 FP 14 3139ϩ42AtoT/- N34S/- 25 FP 28 -/- N34S/- 26 FP 36 -/- N34S/- 27 SP 8 -/- N34S/- 28 SP 9 -/- N34S/- 29 SP 3 -/- N34S/- FP, familial pancreatitis; SP, sporadic pancreatitis. Login to comment
90 Also identified were 6 mutations (IVS8 T5, p.D443Y, p.G576A, p.F508C, p.I807M, p.M952T) reported to cause a milder form of CF or other CF-related diseases (such as congenital absence of the vas deferens), which we have categorized as CF mild. Login to comment
104 In patients with SPINK1 mutations, CFTR variants were most commonly observed in exons 3 (eg, p.R75Q) and 10 (eg, p.F508C, c.1584GtoA, p.F508del) and IVS8/exon 9 (T5/TG12 or TG13) (Tables 1 and 3). Login to comment
136 CFTR Mutation Class Types and Corresponding Disease Severity CFTR mutation Exon CF mutation class Disease association % Carriers, case (n) % Carriers, controls (n) p.R75Q 3 "CP" 16.2 (80) 5.3 (525) c.1584GtoA (p.E528E) 10 "CP" 8.7 (80) 3.3 (150) p.F508del 10 II CF severe 8.7 (80) 2.3 (525) p.R560T 11 II CF severe 3.4 (29) 0 (95) IVS8 T5/TG12or13 i8 V CF mild 5.0 (80) 2.7 (150) p.F508C 10 CF mild 1.2 (80) 0 (150) p.I807M 13 CF mild 3.4 (29) 0 (95) p.D443YϩG576AϩR668Ca 9;12;13 CF mild 3.4 (29) 0 (95) p.G576AϩR668Ca 12;13 CF mild 0 (29) 1 (95) p.M952T 15 CF mild 3.4 (29) 0 (95) p.R668C 13 Other 0 (29) 1 (95) c.3139ϩ42AtoT i17a Other 3.4 (29) 0 (95) p.N1432K 24 Other 0 (29) 1 (95) c.-9CtoT 1 Other 0 (29) 1 (95) p.C76W 3 Other 0 (80) 0.7 (150) p.I148T 4 Other 0 (29) 1 (95) c.2657ϩ22GtoA i14b Other 0 (29) 1 (95) p.T1086A 17b Other 0 (29) 1 (95) NOTE. Login to comment

[hide] Preconceptional identification of cystic fibrosis ... J Cyst Fibros. 2011 May;10(3):207-11. doi: 10.1016/j.jcf.2011.02.006. Epub 2011 Mar 22. Coiana A, Faa' V, Carta D, Puddu R, Cao A, Rosatelli MC
Preconceptional identification of cystic fibrosis carriers in the Sardinian population: A pilot screening program.
J Cyst Fibros. 2011 May;10(3):207-11. doi: 10.1016/j.jcf.2011.02.006. Epub 2011 Mar 22., [PMID:21429822]

Abstract [show]
BACKGROUND: In Sardinia the mutational spectrum of CFTR gene is well defined. A mutation detection rate of 94% can be achieved by screening for 15 CFTR mutations with a frequency higher than 0.5%. The efficiency of this molecular test suggests that Sardinians may represent a suitable population for a preconceptional screening. METHODS: Five hundred couples of Sardinia descent were screened for 38 mutations using a semi-automated reverse-dot blot and PCR-gel electrophoresis assays. This mutation panel included the 15 most frequent CF alleles in Sardinia. RESULTS: We identified 38 CF carriers, revealing an overall frequency of 1/25 (4%). The most common CF allele was the p.Thr338Ile (T338I) (65%), followed by the p.Phe508del (F508del) (22.5%). We also identified one couple at risk and an asymptomatic female homozygote for the p.Thr338Ile allele. CONCLUSIONS: In spite of the low number of the couples tested, the results herein reported demonstrate the efficacy and efficiency of the preconceptional screening program and the high participation rate of the Sardinian population (99%).

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88 Mutation nomenclaturea Alleles (%) T338I (p.Thr338Ile) 26 (65.0) F508del (p.Phe508del) 9 (22.5) N1303K (p.Asn1303Lys) 1 (2.5) 2183AANG (c.2051_2052delAAinsG) 1 (2.5) 621+1GNT (c.489+1GNT) 1 (2.5) exon 2 del (c.54-5811_164+2187del8108ins182) 1 (2.5) R347P (p.Arg347Pro) 1 (2.5) The 3849+10kbCNT (c.3717+12191CNT), G85E (p.Gly85Glu), 2789+5GNA (c.2657+5GNA), W1282X (p.Trp1282X), G1244E (p.Gly1244Glu), 711+5GNA (c.579+5GNA), 711+1GNT (c.579+1GNA), 4016insT (p.Ser1297PhefsX5), G542X (p.Gly542X), 1717-1GNA (c.1585-1GNA), R553X (p.Arg553X), Q552X (p.Gln552X), G551D (p.Gly551Asp), S549R (ANC) (p.Ser549Arg), I507del (p.Ile507del), F508C (p.Phe508Cys), I502T (p.Ile502Thr), 1706del17 (p.Gln525LeufsX37), 1677delTA (p.Tyr515X), R117H (p.Arg117His), D1152H (p.Asp1152His), L1065P (p.Leu1065Pro), R1066H (p.Arg1066His), L1077P (p.Leu1077Pro), 4382delA (p.Glu1418ArgfsX14), R1162X (p.Arg1162X), R1158X (p.Arg1158X), 1259 insA (p.Gln378AlafsX4), 852del22 (p.Gly241GlufsX13), S912X (p.Ser912X), and 991del5bp (p.Asn287LysfsX19) mutations included in the CF panel were not detected in the population tested. 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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61 The mutation analysis discriminated between p.F508del and the benign polymorphisms p.F508C, p.I506V, and p.I507V. 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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129 Occasionally, rare variants of IVS8-Tn alleles have been identified in CBAVD males, including for example cases of IVS8-T3-TG12 in trans with F508C [54], IVS8-T2- TG13 in trans with R117H-TG11T9 [63] and IVS8-T6 [64,65]. Login to comment

[hide] Development and validation of a screening test for... Eur Respir J. 1998 Aug;12(2):477-82. Robertson NH, Weston SL, Kelly SJ, Duxbury NJ, Pearce SR, Elsmore P, Webb MB, Newton CR, Little S
Development and validation of a screening test for 12 common mutations of the cystic fibrosis CFTR gene.
Eur Respir J. 1998 Aug;12(2):477-82., [PMID:9727805]

Abstract [show]
The results obtained using deoxyribonucleic acid (DNA) amplification-based tests must be accurate and reproducible. One such test that simultaneously detects any of 12 of the most common mutations of the cystic fibrosis transmembrane conductance regulator gene is presented in this report. An investigation was conducted into how changes of primer, DNA template and Taq DNA polymerase concentrations and of polymerase chain reaction annealing temperatures affect the test. A total of 383 DNA samples obtained from different laboratories was then examined. The preliminary studies defined the conditions under which accurate results are obtained even if the test is performed under suboptimal conditions. Subsequently, 377 (98.4%) of the DNA samples analysed were in full agreement with DNA typing results derived by other methods. The remaining 1.6% of samples were not mistyped, rather they were not scored owing to failure to detect control DNA sequences. These were also archival DNA preparations rather than freshly prepared samples from venous blood. Careful primer design and optimization of reaction conditions are important in the development of multiplex deoxyribonucleic acid amplification-based diagnostic tests. Providing the recommended protocols are followed, the test described here is simple to carry out, gives accurate results and works well if performed within defined operational windows for each reaction variable.

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38 For example, ∆F508 and non-∆F508 alleles should not be confused with either the mutant ∆I507 or the benign F508C allele. Login to comment
86 There was no mistyping when ∆I507, 1717-2A>G, R1283M, R117C, 3617G/T, 621+2T>C or F508C alleles were present. Login to comment
113 CUPPENS and CASSIMAN [20] demonstrated that 12.5% of laboratories mistyped the F508C polymorphism as a true mutation and that 12.5% confused the ∆I507 mutation for ∆F508. Login to comment
117 The CF(12)m test discriminates accurately between ∆F508 and non-∆F508 alleles which, in turn, are distinguished from the mutant ∆I507 and the benign F508C alleles, although the mutant ∆I507 allele is not detected using the kit. Login to comment

[hide] A T3 allele in the CFTR gene exacerbates exon 9 sk... Hum Mutat. 2005 Jan;25(1):72-81. Disset A, Michot C, Harris A, Buratti E, Claustres M, Tuffery-Giraud S
A T3 allele in the CFTR gene exacerbates exon 9 skipping in vas deferens and epididymal cell lines and is associated with Congenital Bilateral Absence of Vas Deferens (CBAVD).
Hum Mutat. 2005 Jan;25(1):72-81., [PMID:15580565]

Abstract [show]
The different alleles at the (TG)m(T)n polymorphic loci at the 3' end of the human CFTR intron 8 determine the efficiency by which exon 9 is spliced. We identified a novel TG12T3 allele in a congenital bilateral absence of vas deferens (CBAVD) patient who carries a [TG11T7; p.Phe508Cys; p.Met470Val] haplotype on the other chromosome. To better understand the complex regulation of exon 9 splicing, we analyzed the levels of correctly spliced CFTR transcripts in six CFTR-expressing epithelial cell lines derived from lung, colon, testis, vas deferens, and epididymis transiently transfected with four CFTR minigenes (pTG11T7, pTG12T7, pTG12T5, and pTG12T3). In this work, we show that a decrease in the Ts at the polymorphic locus in a TG12 background determines a cell-type dependent reduction in exon 9+ transcripts that is not related to the basal splicing efficiency in the cell line. These data emphasize the role of the T5 allele in CBAVD and identify the T3 allele as a severe cystic fibrosis (CF) disease-causing mutation. Finally, UV cross-linking experiments demonstrated that tissue-specific trans-acting splicing factors do not contribute to the different patterns of exon 9 splicing found between the cell lines. However, we observed that lower numbers of Ts can alter the binding of TDP-43 (TDP43 or TARDBP) to its specific target ug12 in a tissue-specific manner. Our results support the idea that the ratio of general splicing factors plays a role in the tissue variability of exon 9 alternative splicing.

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1 We identified a novel TG12T3 allele in a congenital bilateral absence of vas deferens (CBAVD) patient who carries a [TG11T7; p.Phe508Cys; p.Met470Val] haplotype on the other chromosome. Login to comment
28 In our study, we report that a second rare allele, TG12T3, is associated with a CBAVD phenotype in a patient with no other apparent mutation in the CFTR genes excepted the so-called benign variation p.Phe508Cys. Login to comment
35 The patient was found to be heterozygous for several sequence variations: c.1522T>G (1655T>G) or p.Phe508Cys and c.1407A>G (1540A>G) or p.Met470Val in exon 10, and c.742+40A>G (875+40A>G) in intron 6a. Login to comment
46 The numbering of the reported mutations is as follows: c.1522T4G or p.Phe508Cys (recommended nomenclature) and 1655T4G (traditional nomenclature); c.1407A4G or p.Met470Val (recommended nomenclature) and 1540A4G (traditional nomenclature); c.742+40A4G (recommended nomenclature) and 875+40A4G (traditional nomenclature); c.1209-6Tn (recommended nomenclature) for the polymorphic locus in intron 8 and IVS8-6T(n) or c.1342-6Tn (traditional nomenclature). Login to comment
233 The second case is the adult with CBAVD described here, carrying a different genotype [TG12T3] +[p.Phe508Cys;TG11T7]. Login to comment

[hide] UMD-CFTR: a database dedicated to CF and CFTR-rela... Hum Mutat. 2010 Sep;31(9):1011-9. Bareil C, Theze C, Beroud C, Hamroun D, Guittard C, Rene C, Paulet D, Georges M, Claustres M
UMD-CFTR: a database dedicated to CF and CFTR-related disorders.
Hum Mutat. 2010 Sep;31(9):1011-9., [PMID:20607857]

Abstract [show]
With the increasing knowledge of cystic fibrosis (CF) and CFTR-related diseases (CFTR-RD), the number of sequence variations in the CFTR gene is constantly raising. CF and particularly CFTR-RD provide a particular challenge because of many unclassified variants and identical genotypes associated with different phenotypes. Using the Universal Mutation Database (UMD) software we have constructed UMD-CFTR (freely available at the URL: http://www.umd.be/CFTR/), the first comprehensive relational CFTR database that allows an in-depth analysis and annotation of all variations identified in individuals whose CFTR genes have been analyzed extensively. The system has been tested on the molecular data from 757 patients (540 CF and 217 CBAVD) including disease-causing, unclassified, and nonpathogenic alterations (301 different sequence variations) representing 3,973 entries. Tools are provided to assess the pathogenicity of mutations. UMD-CFTR also offers a number of query tools and graphical views providing instant access to the list of mutations, their frequencies, positions and predicted consequences, or correlations between genotypes, haplotypes, and phenotypes. UMD-CFTR offers a way to compile not only disease-causing genotypes but also haplotypes. It will help the CFTR scientific and medical communities to improve sequence variation interpretation, evaluate the putative influence of haplotypes on mutations, and correlate molecular data with phenotypes.

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111 Four variants can be classified into two different categories: p.Phe508Cys (complex allele, mutation), c.1210À12T[5] (mutation, UV), p.Ser1251Asn (complex allele, mutation), p.Arg74Trp (complex allele, UV). Login to comment

[hide] Evaluation of the disease liability of CFTR varian... Methods Mol Biol. 2011;742:355-72. Sosnay PR, Castellani C, Corey M, Dorfman R, Zielenski J, Karchin R, Penland CM, Cutting GR
Evaluation of the disease liability of CFTR variants.
Methods Mol Biol. 2011;742:355-72., [PMID:21547743]

Abstract [show]
Over 1600 novel sequence variants in the CFTR gene have been reported to the CF Mutation Database (http://www.genet.sickkids.on.ca/cftr/Home.html). While about 25 mutations are well characterized by clinical studies and functional assays, the disease liability of most of the remaining mutations is either unclear or unknown. This gap in knowledge has implications for diagnosis, therapy selection, and counseling for patients and families carrying an uncharacterized CFTR mutation. This chapter will describe a critical approach to assessing the disease implications of CFTR mutations utilizing clinical data, literature review, functional testing, and bioinformatic in silico methods.

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140 The bioinformatic tools PolyPhen and SIFT have been employed to evaluate amino acid changes in CFTR, but made significant errors incorrectly identifying "known" neutral polymorphisms p.Phe508Cys and p.Ile148Thr as likely to be deleterious (58, 59). Login to comment

[hide] A model for the nucleotide-binding domains of ABC ... Proteins. 1998 Feb 15;30(3):275-86. Hoedemaeker FJ, Davidson AR, Rose DR
A model for the nucleotide-binding domains of ABC transporters based on the large domain of aspartate aminotransferase.
Proteins. 1998 Feb 15;30(3):275-86., [PMID:9517543]

Abstract [show]
ABC transporters are a large superfamily of integral membrane proteins involved inATP-dependent transport across biological membranes. Members of this superfamily play roles in a number of phenomena of biomedical interest, including cystic fibrosis (CFTR) and multidrug resistance (P-glycoprotein, MRP). Most ABC transporters are predicted to consist of four domains, two membrane-spanning domains and two cytoplasmic domains. The latter contain conserved nucleotide-binding motifs. Attempts to determine the structure of ABC transporters and of their separate domains are in progress but have not yet been successful. To aid structure determination and possibly learn more about the domain boundaries, we set out to model nucleotide-binding domains (NBDs) of ABC transporters based on a known structure. Previous attempts to predict the 3D structure of NBDs were based solely on sequence similarity with known nucleotide-binding folds. We have analyzed the sequences of a number of nucleotide-binding domains with the algorithm THREADER, developed by D.T. Jones, and a possible fold was found in the structure of aspartate aminotransferase. We present a model for the N-terminal NBD of CFTR, based on the large domain of the A chain of aspartate aminotransferase. The model is refined using multiple sequence alignment, secondary structure prediction, and 3D-1D profiles. Our model seems to be in good agreement with known properties of nucleotide-binding domains and has some appealing characteristics compared with the previous models.

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153 The observation that a point mutation at this position (F508C) is benign35 Fig. 4. 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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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] 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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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
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] 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
138 Researchers found that the phenotypic severity of a CF-causing mutation could be impacted by the genomic context of the CFTR gene as seen when R117H is in cis with the 5T variant and when S1251N is in cis with F508C [33,34]. Login to comment

[hide] Extensive molecular analysis of patients bearing C... J Mol Diagn. 2012 Jan;14(1):81-9. Epub 2011 Oct 20. Amato F, Bellia C, Cardillo G, Castaldo G, Ciaccio M, Elce A, Lembo F, Tomaiuolo R
Extensive molecular analysis of patients bearing CFTR-related disorders.
J Mol Diagn. 2012 Jan;14(1):81-9. Epub 2011 Oct 20., [PMID:22020151]

Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR)-related disorders (CFTR-RDs) may present with pancreatic sufficiency, normal sweat test results, and better outcome. The detection rate of mutations is lower in CFTR-RD than in classic CF: mutations may be located in genes encoding proteins that interact with CFTR or support channel activity. We tested the whole CFTR coding regions in 99 CFTR-RD patients, looking for gene mutations in solute carrier (SLC) 26A and in epithelial Na channel (ENaC) in 33 patients who had unidentified mutations. CFTR analysis revealed 28 mutations, some of which are rare. Of these mutations, RT-PCR demonstrated that the novel 1525-1delG impairs exon 10 splicing; by using minigene analysis, we excluded the splicing effect of three other novel intronic variants. Analysis of SLC26A genes revealed several variants, some of which are novel, that did not affect mRNA expression. Other mutations occurred in the ENaC genes encoding the ENaC subunits, but their frequency did not significantly differ between patients and controls. Our data, although obtained on a preliminary cohort of CFTR-RD patients, exclude a role of mutations in SLC26A and in SCNN genes in the pathogenesis of such disease; we confirm that CFTR analysis has a relevant role in CFTR-RD patients; and it appears mandatory to use CFTR scanning techniques and approaches to reveal the effect of novel mutations.

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69 Allele Frequency and CFTR Mutations in Patients Bearing CFTR-RDs Mutation (traditional name) HGVS nomenclature15 CBAVD (118 alleles)* RP (42 alleles)* DB (38 alleles)* Total (198 alleles)* TG12-T5-470V 34 (28.8) 2 (4.8) 10 (26.3) 46 (23.2) F508del c.1521_1523del 19 (16.1) 7 (16.7) 4 (10.5) 30 (15.2) 3195del6 c.3063_3069del 9 (7.6) 0 0 9 (4.5) N1303K c.3909CϾG 3 (2.5) 1 (2.4) 4 (10.5) 8 (4.0) G542X c.1624GϾT 4 (3.4) 1 (2.4) 1 (2.6) 6 (3.0) D1152H c.3454GϾC 1 (0.8) 2 (4.8) 2 (5.3) 5 (2.5) G85E c.254GϾA 2 (1.7) 3 (7.1) 0 5 (2.5) 1525-1delG c.1394de 3 (2.5) 1 (2.4) 0 4 (3.0) 4016insT c.3885insT 2 (1.7) 1 (2.4) 0 3 (1.5) 2789ϩ5GϾA c.2657ϩ5GϾA 0 3 (7.1) 0 3 (1.5) Q1476X c.4426CϾT 3 (2.5) 0 0 3 (1.5) 2183AAϾG c.2051_2052delinsG 1 (0.8) 1 (2.4) 0 2 (1.0) R553X c.1657CϾT 1 (0.8) 1 (2.4) 0 2 (1.0) L568F c.1704GϾT 2 (1.7) 0 0 2 (1.0) R1158X c.3472CϾT 2 (1.7) 0 0 2 (1.0) V920M c.2758GϾA 1 (0.8) 0 1 (2.6) 2 (1.0) 711ϩ1GϾT c.579ϩ1GϾT 0 1 (2.4) 0 1 (0.5) D614G c.1841AϾG 1 (0.8) 0 0 1 (0.5) 2184insA c.2052del 0 1 (2.4) 0 1 (0.5) 621ϩ1GϾT c.489ϩ1GϾT 1 (0.8) 0 0 1 (0.5) R1438W c.4312CϾT 0 1 (2.4) 0 1 (0.5) E193X c.577GϾT 0 1 (2.4) 0 1 (0.5) G1244E c.3731GϾA 1 (0.8) 0 0 1 (0.5) K68E c.202AϾG 1 (0.8) 0 0 1 (0.5) R347P c.1040GϾC 1 (0.8) 0 0 1 (0.5) 621ϩ3AϾG c.489ϩ3AϾG 1 (0.8) 0 0 1 (0.5) L997F c.2991GϾC 0 1 (2.4) 0 1 (0.5) F508C c.1523TϾG 1 (0.8) 0 0 1 (0.5) Total 94 (79.7) 28 (66.7) 22 (57.9) 144 (72.7) Undetected 24 (20.3) 14 (33.3) 16 (42.1) 54 (27.3) *Data are given as number (percentage). Login to comment
90 The RT-PCR analysis of CFTR RNA from nasal cells, followed by electrophoresis, was performed in a patient bearing the 1525-1delG mutation and F508C on the other allele. Login to comment

[hide] CFTR mutations in the Algerian population. J Cyst Fibros. 2008 Jan;7(1):54-9. Epub 2007 Jun 14. Loumi O, Ferec C, Mercier B, Creff J, Fercot B, Denine R, Grangaud JP
CFTR mutations in the Algerian population.
J Cyst Fibros. 2008 Jan;7(1):54-9. Epub 2007 Jun 14., [PMID:17572159]

Abstract [show]
The nature and frequency of the major CFTR mutations in the North African population remain unclear, although a small number of CFTR mutation detection studies have been done in Algeria and Tunisia, showing largely European mutations such as F508del, G542X and N1303K, albeit at different frequencies, which presumably emerged via population admixture with Caucasians. Some unique mutations were identified in these populations. This is the first study that includes a genetic and clinical evaluation of CF patients living in Algeria. In order to offer an effective diagnostic service and to make accurate risk estimates, we decided to identify the CFTR mutations in 81 Algerian patients. We carried out D-HPLC, chemical-clamp denaturing gradient gel electrophoresis, multiplex amplification analysis of the CFTR gene and automated direct DNA sequencing. We identified 15 different mutations which account for 58.5% of the CF chromosomes. We used a quantitative PCR technique (quantitative multiplex PCR short fragment fluorescence analysis) to screen for deletion/duplication in the 27 exons of the gene. Taking advantage of the homogeneity of the sample, we report clinical features of homozygous CF patients. As CFTR mutations have been detected in males with infertility, 46 unrelated Algerian individuals with obstructive azoospermia were also investigated.

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119 Only the 5 heterozygotes have been analysed by D-HPLC and QMPSF, one of them presented a combination of sequence variation as F508C, M470V and 1525-61A/G, classified as polymorphisms in the CFGAC [27]. 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

[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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27 I506C, I507V, and F508C are performed only as reflex tests for unexpected homozygosity for ΔF508 and/or ΔI507. Login to comment
104 Nucleotides were added to the 5' and 3' ends of the probe sequences to improve hybridization efficiency of the probe to its perfect-match target, thus 152 Dunbar and Jacobson Table 2 (Continued) Target Microsphere Probe sequence Modificationb Sequence 5' → 3' set 46B 1898+1G→A 5'-AmMC12 TATTTGAAAGATATGTTCTTTG 027 47B 3120+1G 5'-AmMC12 CTTCATCCAGGTATGTAAAAAT 043 48B 3120+1G→A 5'-AmMC12 CTTCATCCAGATATGTAAAAAT 055 Reflex panel R2B I506V 5'-AmMC12 CACCAAAGATGACATTTTC 009 R3B I507V 5'-AmMC12 CACCAAAGACGATATTTTC 021 R4B F508C 5'-AmMC12 AACACCACAGATGATATTT 024 R5B 5T 5'-AmMC12 TGTGTGTTTTTAACAGGG 029 R6B 7T 5'-AmMC12 GTGTGTTTTTTTAACAGG 033 R7C 9T 5'-AmMC12 GTGTGTTTTTTTTTAACAG 037 a The position and sequence of the mutation or variation is indicated in bold type. b 5'-Amino modifier C12. 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
124 The M1 reaction was also used for detection of the I506V, I507V, and F508C polymorphisms in the reflex panel. Login to comment
259 Table7(continued) 167 Table 8 Allelic Ratio Data for the Reflex Panela Genotype I507 & F508 I506V I507Vb F508C Exon 10 variants ΔF508/ΔF508c - - - - ΔF508/Normal 0.93 0.03 0.02 0.02 Normal/Normal 0.94 0.03 0.01 0.01 ΔI507/Normal 0.97 0.04 -0.03 0.01 I506V/Normal 0.45 0.01 -0.01 0.54 F508C/Normal 0.40 0.58 0.00 0.01 Intron 8 variants Genotype 5T 7T 9T 7T/7T -0.06 1.06 0.01 7T/7T -0.01 1.00 0.01 7T/7T -0.01 1.01 0.00 9T/9T 0.05 0.05 0.90 9T/9T 0.07 0.05 0.87 7T/9T 0.04 0.45 0.51 7T/9T 0.03 0.40 0.56 5T/7T 0.42 0.60 -0.01 5T/7T 0.45 0.59 -0.04 5T/9T 0.36 0.00 0.64 a Positive alleles are indicated in bold type. b Samples positive for the I507V allele were not available. 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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No. Sentence Comment
68 of chromosomes (frequency %) p.M1V 1 1 (0.23) p.M1K 1 1 (0.23) c.300delA 3 1 (0.23) p.P67L 3 1 (0.23) c.359insT 3 1 (0.23) p.G85E 3 3 (0.70) c.394delTT 3 1 (0.23) p.Q98R 4 1 (0.23) p.R117H 4 2 (0.47) p.Y122X 4 2 (0.47) p.Y161N 4 1 (0.23) c.621+1GNT intron 4 1 (0.23) c.621+2TNG intron 4 1 (0.23) p.I175V 5 2 (0.47) c.711+1GNT intron 5 5 (1.16) p.L206W 6 3 (0.70) p.Q220X 6 1 (0.23) p.L227R 6 1 (0.23) c.1078delT 7 2 (0.47) p.R334W 7 7 (1.63) p.R347P 7 2 (0.47) c.1215delG 7 1 (0.23) c.T5 intron 8 1 (0.23) p.D443Y 9 1 (0.23) p.I506T 10 1 (0.23) p.I507del 10 4 (0.93) p.F508del 10 259 (60.23) p.F508C 10 1 (0.23) c.1677delTA 10 1 (0.23) c.1717-8GNA intron 10 1 (0.23) c.1717-1GNA intron 10 6 (1.40) p.G542X 11 23 (5.35) p.S549R 11 1 (0.23) p.G551D 11 2 (0.47) p.R553X 11 1 (0.23) c1811+1.6kbANG intron 11 4 (0.93) c.1812-1GNA intron 11 1 (0.23) p.T582I 12 1 (0.23) p.E585X 12 2 (0,47) c.1898+1GNA intron 12 1 (0.23) [c.1898+5GNA ;p.E725K] intron 12 1 (0.23) c.1898+73TNG intron 12 1 (0.23) c.2183AANG 13 4 (0.93) c.2184insA 13 1 (0.23) p.K710X 13 4 (0.93) c.2423delG 13 1 (0.23) p.S776X 13 1 (0.23) c.2493ins8 13 1 (0.23) p.R792X 13 1 (0.23) p.K830X 13 1 (0.23) p.D836Y 14a 1 (0.23) p.W846X1 14a 1 (0.23) c.2711delT 14a 1 (0.23) c.2789+5GNA intron 14b 3 (0.70) p.S945L 15 3 (0.70) p.D993Y 16 1 (0.23) c.3129del4 17a 1 (0.23) c.3195del6 17a 1 (0.23) c.3272-26ANG intron 17a 1 (0.23) [c.3395insA ;pI148T] 17b/4 1 (0,23) p.Y1092X 17b 3 (0.70) Table 1 (continued) Mutation Location exon/intron No. 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] 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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66 Five sequence changes (R31C, R75Q, F508C, G576A, R1162L) were reported as ''mutations`` in the forms; however, they are listed as ''polymorphisms`` in the CFGAC (designed respectively as 223C/T, 356G/A, 1655T/G, 1859G/ C, and 3617G>T). Login to comment
68 However, at least three of these changes are listed as neutral polymorphisms in the CFGAC: L467F (1531C/T), F508C (1655T/G), and I1027T (3212T/C). Login to comment
109 h M1K, K14X, W19X, 211delG, G27E, R31C, 237insA, 241delAT, Q39X, 244delTA, 296+2T>C, 297-3C>T, W57X+F87L, 306delTAGA, P67L, A72D, 347delC, R75Q, 359insT, 394delT, 405+4A>G, Q98R, 457TAT>G, R117H+5T, R117H+I1027T, R117L, R117P, H139R, A141D, M152V, N186K, D192N, D192del, E193X, 711+1G>A, 711+3A>G, 712-1G>T, L206F, W216X, C225R, Q237E, G241R, 852del22, 876-14del12, 905delG, 993del5, E292K, Y304X, F311del, 1161delC, R347L, R352Q, W361R, 1215delG, S364P, S434X, D443Y, S466X, C491R, T501A, I506T, F508C, I507del+F508C, F508del+L467F, 1774delCT, R553G, 1802delC, 1806delA, A559E, Y563N, 1833delT, Y569C, Y569H, Y569X, G576X, G576A, T582I, 1898+3A>G+186-13C>G, 1918delGC, R600G, L610S, G628R, 2043delG, 2118del4, E664X, 2174insA, Q689X, K698R, K716X, L732X, 2347delG, 2372del8, R764X, 2423delG, S776X, 2634insT, 2640delT, C866Y, 2752-1G>T, W882X, Y913C, V920M, 2896insAG, H939D, H939R, D979V, D985H, D993Y, 3120G>A, I1005R, 3195del6, 3293delA, 3320ins5, W1063X, A1067T, 3359delCT, T1086I, W1089X, Y1092X+S1235R, W1098X, E1104X, R1128X, 3532AC>GTA, 3548TCAT>G, M1140del, 3600G>A, R1162L, 3667ins4, 3732delA+K1200E, S1206X, 3791delC, S1235R+5T, Q1238R, Q1238X, 3849+4A>G, T1246I, 3869insG, S1255P, R1283K, F1286S, 4005+1G>T, 4006-8T>A, 4015delA, N1303H, N1303I, 4172delGC, 4218insT, 4326delTC, Q1382X, 4375-1C>T, 4382delA, D1445N, CF40kbdel4-10, Cfdel17b. Login to comment

[hide] Screening practices for mutations in the CFTR gene... Hum Mutat. 2000;15(2):135-49. Girodon-Boulandet E, Cazeneuve C, Goossens M
Screening practices for mutations in the CFTR gene ABCC7.
Hum Mutat. 2000;15(2):135-49., [PMID:10649490]

Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR) gene studies are now one of the most frequent activities in clinical molecular genetics laboratories. The number of requests is growing, owing to the increasingly wide range of recognized CFTR gene diseases (cystic fibrosis, congenital bilateral absence of the vas deferens, disseminated bronchiectasis, allergic bronchopulmonary aspergillosis and chronic pancreatitis), and the availability of efficient molecular tools for detecting mutations. A growing number of tests capable of simultaneously detecting several frequent CF mutations are being developed, and commercial kits are now available. The most recent kits detect nearly 90% of defective alleles in Caucasians, a rate high enough for carrier screening and for the majority of diagnostic requests. However, because of the wide variety of molecular defects documented in the CFTR gene, only a limited number of laboratories have mastered the entire panoply of necessary techniques, while other laboratories have to refer certain cases to specialized centers with complementary and/or scanning tools at their disposal. A good knowledge of CFTR diseases and their molecular mechanisms, together with expertise in the various techniques, is crucial for interpreting the results. Diagnostic strategies must take into account the indication, the patient's ethnic origin, and the time available in the framework of genetic counseling. This review presents the methods most frequently used for detecting CFTR gene mutations, and discusses the strategies most suited to the different clinical settings.

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81 For example, an allele bearing the 1655T/G (F508C) polymorphism may not be recognized when using F508- or∆F508- specific probes in hybridization-based methods; with the PE Biosystems OLA kit, the presence of the 3617G/T (R1162L) polymorphism prevents ligation with the normal R1162 and mutated X1162 probes, while a∆F508 homozygous signal may correspond to∆F508 / 1716G/A (E528E) compound heterozygosity, as the 3' primer for PCR of exon 10 includes the 3' end of this exon. 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

[hide] Genetic findings in congenital bilateral aplasia o... Hum Mutat. 1998;11(6):480. de Meeus A, Guittard C, Desgeorges M, Carles S, Demaille J, Claustres M
Genetic findings in congenital bilateral aplasia of vas deferens patients and identification of six novel mutatations. Mutations in brief no. 138. Online.
Hum Mutat. 1998;11(6):480., [PMID:10200050]

Abstract [show]
Congential bilateral aplasia of vas deferens (CBAVD), a form of male sterility, has been suggested to represent a "genital" form of cystic fibrosis (CF), as mutations in the CFTR gene have been identified in most patients with this condition. Interestingly, the 5T allele in intron 8 appeared to be the most frequent mutation associated with CBAVD. However, the molecular basis of CBAVD is not completely understood. We have analysed the complete coding and flanking CFTR sequences by PCR-DGGE in 64 men with CBAVD from southern France with the aim to list any sequence alteration. Fourty-two of the 64 patients (65.6%) had mutations on both copies of the CFTR gene, including one patient with two mutations in the same copy (DF508 + A1067T). The 5T allele was present in 21/64 cases (33%). Six of the 28 different mutations identified in this study had never been described previously, and appeared to be specific to CBAVD (P111L, M244K, A1364V, G544V, 2896insAG,-33G->A).

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83 Phenotype CFTRamutations Intron 8, Poly(T) tract 1 3 crisis of acute pancreatitis F508 / L206W 9/7 2 F508 / L206W 9/9 3 frequent bronchitis F508 / R347H 9/9 4 F508 / R347H 9/9 5 F508 / M244K 9/7 6 F508 / A1364V 9/7 7 F508 / D1152H 9/7 8 chronic sinusitis and bronchitis F508 / D1152H 9/7 9 F508 / R117H 9/7 10 F508 / R117H 9/7 11 F508 / M952I 9/7 12 D443Y / G542X 7/9 13 D443Y / G542X 7/9 14 2184delA / D443Y 7/7 15 2184delA / D443Y 7/7 16 R347H / D443Y 9/7 17 seminal vesicles agenesia R117H / G1349D 7/7 18 R117H / G1244E 7/7 19 N1303K / P111L 9/7 20 chronic sinusitis, nasal polyps W1282X / D1152H 7/7 21 chronic sinusitis R347H / Y1092X 7/7 22 seminal vesicles agnesia 297-3C-GTT / 4279insA 7/7 23 G544V / F508C 7/7 24 D1152H / 2896insAG 7-9 25 F508 / - 9/5 26 F508 / - 9/5 27 F508 / - 9/5 28 F508 / - 9/5 29 F508 / - 9/5 30 chronic sinusitis, bronchitis F508 / - 9/5 31 sinusitis and allergy F508 / - 9/5 32 allergy F508 / - 9/5 33 F508 / - 9/5 34 F508 / - 9/5 35 F508 / - 9/5 36 F508 / - 9/5 37 bronchitis, asthma F508 / - 9/5 38 chronic sinusitis F508+A1067T / - 9/5 39 chronic sinusitis D1152H / - 7/5 40 2184delA / - 7/5 41 R764X / - 7/5 42 711+1G-GTT / - 7/5 43 F508 / - 9/7 44 F508 / - 9/7 45 F508 / - 9/7 46 F508 / - 9/9 47 R553X / - 7/7 48 -33G-GTA / - 7/7 49 K710X / - 7/7 50 - / - 5/5 51 - / - 5/7 52 - / - 5/7 53 - / - 7/7 54 - / - 7/7 55 - / - 7/7 56 - / - 7/7 57 - / - 7/7 58 - / - 7/7 59 - / - 7/7 60 - / - 7/7 61 - / - 7/9 62 - / - 7/9 63 NIDDb - / - 7/9 64 - / - 7/9 a : Cystic Fibrosis Transmembrane Regulator gene b : Non Insulino-Dependant Diabetis References Anguiano A, Oates RD, Amos JA, Dean M, Gerrard B, Stewart C, Maher TA, White MB, Milunsky A (1992) Congenital absence of the vas deferens: a primarily genital form of cystic fibrosis. Login to comment

[hide] Comparison of the bacterial HelA protein to the F5... J Bacteriol. 1997 Dec;179(24):7869-71. Goldman BS, Sherman DA, Kranz RG
Comparison of the bacterial HelA protein to the F508 region of the cystic fibrosis transmembrane regulator.
J Bacteriol. 1997 Dec;179(24):7869-71., [PMID:9401049]

Abstract [show]
The HelA protein of Rhodobacter capsulatus is the ATP-binding-cassette subunit of an exporter complex required for cytochrome c biogenesis. By primary sequence comparisons the F88 residue of HelA is similar to the F508 residue of the cystic fibrosis transmembrane regulator (CFTR) protein. Previous studies have established that CFTR F508delta or F508R proteins are defective but F508C is functional. Our results demonstrate that the HelA F88 mutants functionally mimic the phenotypes of known CFTR F508 mutants. The phenotypes of additional HelA mutants and the in vivo steady-state levels of these proteins are also reported.

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7 Previous studies have established that CFTR F508⌬ or F508R proteins are defective but F508C is functional. Login to comment
64 The CFTR F508⌬ was from many CF patients and in vitro analyses, and F508C was found in a benign case (20). 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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33 Importantly, missense mutations such as F508C, I506V and I507V are benign and do not cause the disease [Kobayashi et al. (1990)]. Login to comment

[hide] Distinct spectrum of CFTR gene mutations in congen... Hum Genet. 1997 Sep;100(3-4):365-77. Dork T, Dworniczak B, Aulehla-Scholz C, Wieczorek D, Bohm I, Mayerova A, Seydewitz HH, Nieschlag E, Meschede D, Horst J, Pander HJ, Sperling H, Ratjen F, Passarge E, Schmidtke J, Stuhrmann M
Distinct spectrum of CFTR gene mutations in congenital absence of vas deferens.
Hum Genet. 1997 Sep;100(3-4):365-77., [PMID:9272157]

Abstract [show]
Congenital absence of the vas deferens (CAVD) is a frequent cause for obstructive azoospermia and accounts for 1%-2% of male infertility. A high incidence of mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene has recently been reported in males with CAVD. We have investigated a cohort of 106 German patients with congenital bilateral or unilateral absence of the vas deferens for mutations in the coding region, flanking intron regions and promotor sequences of the CFTR gene. Of the CAVD patients, 75% carried CFTR mutations or disease-associated CFTR variants, such as the "5T" allele, on both chromosomes. The distribution of mutation genotypes clearly differed from that observed in cystic fibrosis. None of the CAVD patients was homozygous for delta F508 and none was compound heterozygous for delta F508 and a nonsense or frameshift mutation. Instead, homozygosity was found for a few mild missense or splicing mutations, and the majority of CAVD mutations were missense substitutions. Twenty-one German CAVD patients were compound heterozygous for delta F508 and R117H, which was the most frequent CAVD genotype in our study group. Haplotype analysis indicated a common origin for R117H in our population, whereas another frequent CAVD mutation, viz. the "5T allele" was a recurrent mutation on different intragenic haplotypes and multiple ethnic backgrounds. We identified a total of 46 different mutations and variants, of which 15 mutations have not previously been reported. Thirteen novel missense mutations and one unique amino-acid insertion may be confined to the CAVD phenotype. A few splice or missense variants, such as F508C or 1716 G-->A, are proposed here as possible candidate CAVD mutations with an apparently reduced penetrance. Clinical examination of patients with CFTR mutations on both chromosomes revealed elevated sweat chloride concentrations and discrete symptoms of respiratory disease in a subset of patients. Thus, our collaborative study shows that CAVD without renal malformation is a primary genital form of cystic fibrosis in the vast majority of German patients and links the particular expression of clinical symptoms in CAVD with a distinct subset of CFTR mutation genotypes.

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11 A few splice or missense variants, such as F508C or 1716 G→A, are proposed here as possible candidate CAVD mutations with an apparently reduced penetrance. Login to comment
89 This study Variants: R75Qg G→A at 356 exon 3 2 A2 Zielenski et al. (1991b) T351S C→G at 1184 exon 7 1 C4 Mercier et al. (1993) 5Th reduction of oligoT tract to 5T at 1342-12 intron 8 26 C2, A4, D3, A2 Chu et al. (1991) F508C T→G at 1655 exon 10 3 C2 Kobayashi et al. (1990) 1716 G→A G→A at 1716 exon 10 3 D3 Kerem et al. (1990) G576Ai G→C at 1859 exon 12 2 D3 Fanen et al. (1992) R668Ci C→T at 2134 exon 13 2 D3 Fanen et al. (1992) S1235R T→G at 3837 exon 19 1 n.p. Cuppens et al. (1993) Q1352Hh G→C at 4188 exon 22 2 C2 Nukiwa and Seyama (pers. comm.) a The nomenclature of mutations follows Beaudet and Tsui (1993) The symbol "̃" is used to designate an amino-acid insertion b Nucleotides are numbered according to the cDNA sequence of Riordan et al. (1989) c Exons and introns are numbered according to Zielenski et al. (1991a) d Allele frequency is given as number of chromosomes e Haplotypes were defined as listed in B below. Login to comment
109 Splicing variants, such as "5T" or 1716 G→A, and missense variants, such as F508C or the 369 Table 1B Dimorphic marker haplotypes. Login to comment
129 The less frequent F508C variant was initially reported to be benign (Kobayashi et al. 1990) but is present in three of our CBAVD males who are all compound heterozygous for ∆F508 and F508C with no other detected mutation (one patient has been reported previously by Meschede et al. 1993). Login to comment
134 The Q1352H mutation may be insufficient to cause CBAVD but the additional occurrence of one "5T" 370 Variant Allele frequency n (% of chromosomes) Random donors Non-CF CBAVD CF 125G→C 15/178 (8.5%) n.d. 2/212 (0.9%) 1/1000 (0.1%)a R75Q 4/188 (2.2%) 3/130 (2.1%) 2/212 (0.9%)b 1/1000 (0.1%) 5T 9/186 (4.8%) 2/65 (2.9%) 26/212 (12.3%)c 3/1000 (0.3%) F508C 0/188 n.d. 3/212 (1.4%) 2/1000 (0.2%)d 1716G→A 5/188 (2.6%) 3/212 (1.5%) 3/212 (1.4%) 2/1000 (0.2%)e G576A-R668C 0/188 n.d. 2/212 (0.9%)f 3/1000 (0.3%)f Table 2 Frequency distribution of CFTR variants in different subgroups of individuals. Login to comment
137 Complex alleles are indicated a One CF allele with R75X and 125G→C b One CBAVD allele with R75Q and R933S c One CBAVD allele with 5T and Q1352H d Two CF alleles with F508C and S1251N e One CF allele with 1716G→A and L619S f G576A and R668C were linked on two CBAVD and three CF alleles, whereas two additional CF alleles carried R668C together with the 3849+10kB C→T mutation (Dörk and Stuhrmann 1995) 371 Table 3 CFTR mutation genotypes in 106 males with CAVD Genotype PolyT Frequency Ethnic descent Diagnosis ∆F508/R117H 9/7 21 German, Austrian 20 CBAVD, 1 CUAVD ∆F508/5T 9/5 9 German, Austrian 8 CBAVD, 1 CUAVD ∆F508/F508C 9/7 3 German CBAVD ∆F508/R347H 9/9 2 German CBAVD ∆F508/1716 G→A 9/7 2 German CBAVD ∆F508/3272-26 A→G 9/7 2 German CBAVD ∆F508/E56K 9/7 1 German CBAVD ∆F508/M265R 9/7 1 German-Portuguese CBAVD ∆F508/R334W 9/9 1 German CBAVD ∆F508/T351S 9/9 1 German CBAVD ∆F508/L375F 9/7 1 Volga German CBAVD ∆F508/G576A & R668C 9/7 1 German CBAVD ∆F508/R933S 9/7 1 German CBAVD ∆F508/L997F 9/9 1 German CBAVD ∆F508/Y1032C 9/7 1 German CBAVD ∆F508/D1152H 9/7 1 German CBAVD ∆F508/K1351E 9/7 1 German CBAVD ∆F508/D1377H 9/7 1 Portuguese CBAVD ∆F508/L1388Q 9/7 1 German CBAVD ∆F508/unknown 9/7 4 German 3 CBAVD, 1 CUAVD 5T/5T 5/5 2 German CBAVD 5T/G542X 5/9 2 German, Turkish CBAVD 5T/D58N 5/7 1 Lebanese CBAVD 5T/̃L138 5/7 1 German-Polish CBAVD 5T/1078delT 5/7 1 German CBAVD 5T/R553X 5/7 1 German CBAVD 5T/2184insA 5/7 1 Turkish CBAVD 5T/D979A 5/7 1 Vietnamese CBAVD 5T/D1152H 5/7 1 Turkish CBAVD 5T/3659delC 5/7 1 German CBAVD 5T/S1235R 5/7 1 Greek CBAVD 5T/W1282X 5/7 1 German CBAVD 5T & Q1352H/ R297W & Q1352H 5/7 1 Vietnamese CBAVD 5T/unknown 5/7 1 German CBAVD R117H/L206W 7/9 1 German CBAVD R117H/2789+5 G→A 7/7 1 German CBAVD R117H/unknown 7/7 1 German CBAVD 2789+5 G→A/2789+5 G→A 7/7 1 Lebanese CBAVD 2789+5 G→A/L973F 7/7 1 German CBAVD V938G/V938G 7/7 1 Greek CBAVD V938G/174delA 7/7 1 German CBAVD D110H/D110H 7/7 1 Turkish CBAVD R334L/I336K 7/7 1 German CBAVD R347H/N1303K 9/9 1 German CBAVD L568F/D1152H 7/7 1 Turkish CBAVD 3272-26 A→G/V1153E 7/7 1 German CBAVD R75Q/unknown 7/7 1 German CBAVD A120T/unknown 9/7 1 German CBAVD 1716G→A/unknown 7/7 1 German CBAVD G576A & R668C/unknown 7/7 1 German CBAVD 2752-15 C→G/unknown 7/7 1 Iranian CBAVD Unknown/unknown 17 German, Turkish 7 CBAVD and 1 CUAVD without observed renal agenesis, 9 CBAVD with renal agenesis allele and the R297W mutation on a homozygous Q1352H background may then reduce CFTR function to a disease-causing level. Login to comment
144 Lung function tests indicated initial pulmonary deterioration in a few cases (FEV1 forced expiratory volume in 1 s, given as percent predicted) Subject Age Genotype Height Weight Sweat C1- Symptoms (years) (cm) (kg) (mM) 1 33 ∆F508/R117H 172 75 46 Dyspnoe 2 37 ∆F508/R117H 178 83 31 Nasal polyposis 3 31 ∆F508/R117H 181 91 n.d. Nasal polyposis 4 32 R117H/unknown 164 70 33 Recurrent infections 5 33 ∆F508/E56K 193 100 85 Sinusitis, recurrent bronchitis 6 31 ∆F508/M265R 192 112 59 Recurrent infections, pancreatitis 7 33 ∆F508/R334W 182 78 n.d. Recurrent infections, pneumonia 8 28 ∆F508/R347H n.d. n.d. n.d. Recurrent infections 9 32 ∆F508/F508C 192 98 32 Pneumonia 10 34 ∆F508/Y1032C n.d. n.d. n.d. Recurrent bronchitis 11 33 ∆F508/3272-26 A→G 172 82 125 Recurrent infections, maldigestion, FEVI 73% 12 28 ∆F508/unknown 185 95 n.d. Login to comment
191 Therefore, missense variants, such as F508C or G576A, or splicing variants, such as 1716 G→A, deserve closer examination with regard to what extent they can impair CFTR function in an epithelial tissue, such as the vas deferens. Login to comment

[hide] False-positive results of genetic testing in cysti... J Pediatr. 1997 Apr;130(4):658-60. Warren WS, Hamosh A, Egan M, Rosenstein BJ
False-positive results of genetic testing in cystic fibrosis.
J Pediatr. 1997 Apr;130(4):658-60., [PMID:9108869]

Abstract [show]
We describe a patient in whom newborn immunoreactive trypsin screening and mutation analysis suggested a diagnosis of cystic fibrosis; however, the clinical course and sweat test results were not consistent with the diagnosis. Direct sequencing of the patient's genomic DNA showed compound heterozygosity for delta F508 and F508C, a polymorphism not associated with clinical disease.

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27 Because of the discrepancy between the results of mutation analysis and the patient's clinical course and sweat electrolyte concentrations, direct sequencing of CFTRexon 10 was carried out with polymerase chain reaction-amplified genomic DNA.3This revefiled compound heterozygosity for AF508 and F508C (Figure), a polymorphism not known to be associated with clinical disease. Login to comment
30 Vertical lines, WT sequenceat codon508;angle brackets, deletionoftheTTC,whichcausesthe AF508mutation;arrow, T---~G transversion,which causes the F508C mutation. Login to comment
32 CFTR beating the AF508 mutation results in a nonfunctional protein.4 The F508C mutation in compound heterozygosity with AF508 has been previously reported in six subjects.6-1°Five were completely free of symptoms, and one had isolated congenital absence of the vas deferens without other stigmata of CF. Login to comment
34 Two German patients with CF were found to carry AF508 on one allele and both F508C and the S1251N mutation on the other allele.11 Several states and districts screen newborn infants for CF because of its high incidence.l'~Screening programs use an assay for rRT, a pancreatic enzyme precursor that is persistently elevated in the blood of infants with CF. Login to comment
40 However, the other allele could not hybridize with the AF508 oligonucleotidebecause it does not contain that sequence, or with the normal oligonucleotide because the T--+G transversion, which gives rise to the F508C polymorphism, prevents hybridization to that sequence. Login to comment
43 This problem was reported previously in a fetus at 25% risk of AF508 homozygosity Who was found to be a AF508/F508C compound heterozygote afterreverse dot blot testing ofhis healthy father showed homozygosity for AF508.1° Sequencing of genomic DNA from both the father and the fetus revealed the compound heterozygosity for AF508/F508C. Login to comment
50 Third, the use of allele-specific oligonucleotide analysis, whether by dot blot or reverse dot blot analysis, will lead to false-positive results in patients who are compound heterozygotes for AF508 and F508C until an oligonucleotide designed to detect the F508C mutation is added to dot blot and reverse dot blot schemes of mutation detection, as has been done by some DNA diagnostic laboratories. Login to comment
26 Because of the discrepancy between the results of mutation analysis and the patient's clinical course and sweat electrolyte concentrations, direct sequencing of CFTRexon 10 was carried out with polymerase chain reaction-amplified genomic DNA.3This revefiled compound heterozygosity for AF508 and F508C (Figure), a polymorphism not known to be associated with clinical disease. Login to comment
29 Vertical lines, WT sequenceat codon508;angle brackets, deletionoftheTTC,whichcausesthe AF508mutation;arrow, T---~G transversion,which causes the F508C mutation. Login to comment
31 CFTR beating the AF508 mutation results in a nonfunctional protein.4 The F508C mutation in compound heterozygosity with AF508 has been previously reported in six subjects.6-1&#b0;Five were completely free of symptoms, and one had isolated congenital absence of the vas deferens without other stigmata of CF. Login to comment
33 Two German patients with CF were found to carry AF508 on one allele and both F508C and the S1251N mutation on the other allele.11 Several states and districts screen newborn infants for CF because of its high incidence.l'~Screening programs use an assay for rRT, a pancreatic enzyme precursor that is persistently elevated in the blood of infants with CF. Login to comment
39 However, the other allele could not hybridize with the AF508 oligonucleotidebecause it does not contain that sequence, or with the normal oligonucleotide because the T--+G transversion, which gives rise to the F508C polymorphism, prevents hybridization to that sequence. Login to comment
42 This problem was reported previously in a fetus at 25% risk of AF508 homozygosity Who was found to be a AF508/F508C compound heterozygote afterreverse dot blot testing ofhis healthy father showed homozygosity for AF508.1&#b0; Sequencing of genomic DNA from both the father and the fetus revealed the compound heterozygosity for AF508/F508C. Login to comment
49 Third, the use of allele-specific oligonucleotide analysis, whether by dot blot or reverse dot blot analysis, will lead to false-positive results in patients who are compound heterozygotes for AF508 and F508C until an oligonucleotide designed to detect the F508C mutation is added to dot blot and reverse dot blot schemes of mutation detection, as has been done by some DNA diagnostic laboratories. Login to comment

[hide] Complex cystic fibrosis allele R334W-R1158X result... Hum Mutat. 1996;8(2):134-9. Duarte A, Amaral M, Barreto C, Pacheco P, Lavinha J
Complex cystic fibrosis allele R334W-R1158X results in reduced levels of correctly processed mRNA in a pancreatic sufficient patient.
Hum Mutat. 1996;8(2):134-9., [PMID:8844211]

Abstract [show]
CFTR alleles containing two mutations have been very rarely found in cystic fibrosis (CF) patients. They provide an opportunity to study the effect of two in cis-interacting gene defects on gene expression. Here, we describe a three-generation CF family with a complex CFTR allele that has not been previously described, containing the missense mutation R334W in exon 7 and the nonsense mutation R1158X in exon 19. Lymphocyte RNA analysis showed that (1) the mRNA corresponding to the complex allele is present although at markedly reduced levels; and (2) the nonsense mutation does not lead to detectable skipping of exon 19. The clinical picture of the patients with the genotype R334W-R1158X/delta F508 is characterized by pancreatic sufficiency and an atypical course of the disease.

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38 Other in cis missense mutations have been reported, namely F508C-Sl251N (Kalin et al., 1992), G628R- S1235R (Mercier et al., 1995) and R74W- D1270N (Verlingue et al., 1993). 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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187 Another important aspect of this homozygous deletion mutant hybridization is the absence of hybridization patterns in the A1507 and F508C probe sets. Login to comment
189 Full-length exon lO/exon 11 targets were used in this experiment, however, the AF508 deletion, the A1507 deletion, and the F508C polymorphism all occur within the space of a six nucleotide sequence. Login to comment
191 As a result, the A1507 and F508C sets do not contain any probes that are fully complementary with a AF508 target. Login to comment
192 A homozygous AF508 target will not hybridize significantly with any probes in the A1507 and F508C sets. Login to comment
228 F508C 5`AAATATCATCTGTGGTGTT3`.Underlined bases are interrogated in the three mutation arrays and deletions are in lowercase letters. Login to comment
231 The AF508 probe set shows a homozygous mutant pattern: however, the two neighboring probe sets, A1507 and F508C, have no probes fully complementary to the mutant target and do not show any significanthybridization (seetext fordetailed explanation). Login to comment
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
247 Their CFTR exon 10 DNA was cloned and sequenced, resulting in their correct assignment as AF508/F508C compound het- TABLE 2. Login to comment
252 erozygotes (Kobayashi et al., 1990).Hybridization tests without probes specific for both sequence variants cannot effectively discriminate between AF508 homozygotes and AF508/F508C heterozygous samples. Login to comment

[hide] Double mutant alleles: are they rare? Hum Mol Genet. 1995 Jul;4(7):1169-71. Savov A, Angelicheva D, Balassopoulou A, Jordanova A, Noussia-Arvanitakis S, Kalaydjieva L
Double mutant alleles: are they rare?
Hum Mol Genet. 1995 Jul;4(7):1169-71., [PMID:8528204]

Abstract [show]
The presence of two different mutations carried by the same CF allele has been demonstrated in four out of 44 Bulgarian CF patients during a systematic search of the entire coding sequence of the CFTR gene. Two of the double mutant alleles include one nonsense and one missense mutation and although the nonsense mutation can be considered to be the main defect, the amino acid substitutions are good candidates for disease-causing mutations as well. One double mutant carries two missense mutations whose contribution to the CF phenotype is difficult to evaluate. The findings suggest that double mutant alleles may be more common than expected and could account for some of the problems in phenotype-genotype correlations. Such alleles may have important implications for molecular diagnosis and genetic counselling.

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50 An additional nucleotide substitution, R553Q, has been shown to result in lower sweat electrolyte values in a patient homozygous for AF5O8 (4) and a combination of a neutral amino acid polymorphism (F508C) with another missense mutation (SI25IN) has been found to result in cystic fibrosis (5). 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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593 Not surprisingly, Rl17H is associated with CF only when the allele also contains Table 2 Examples of complex alleles in the CfTR gene Principal Second site mutationa Location alteration Location Reference R75X exon 3 125G --.. C promoter 57 405 + IG --.. A intron 3 3030G --.. A exon 15 57 R1l7H exon 4 129G --.. C promoter 203 RI17H exon 4 IVS8 : 5T or 7T intron 8 101 R297Q exon 7 IVS8 : 5T or 7T intron 8 60 aF508 exon 10 R553Q exon II 59 aF508 exon 10 1I027T exon I7a 57 8F508 exon 10 deletion of D7S8 500 kb 3' of 186 CfTR S549N exon II R75Q exon 3 205a L619S exon 13 1716G � A exon 10 57 G628R (G � C) exon 13 SI235R exon 19 47 2184insA exon 13 IVS:5T exon 9 J Zielenski, J Bal, 0 Markiewicz, L-C Tsui, unpublished data A800G exon 13 IVS8 : 5T or 7T intran 8 31 S912L exon 15 GI244V exon 20 149 GlO69R exon 17b L88X exon 3 149 3732deiA exon 19 Kl200E exon 19 70 3849 + IOkbC � intron 19 R668C exon 13 57 T SI251N exon 20 F508C exon 10 94 The status of principal mutation may not be clear in every case; e.g. G628R(G --> C) vs S1235R. 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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120 There are, however, only six additional CFTR mutations with a frequency of approximately 1% or more of the CF chromosomes; two nonsense mutations, G542X and R553X, and the missense mutations G551D and NI303K were predominantly seen in severely affected patients, whereas the transmembrane missense mutation R347P and the splice mutation 3849 + 10 kB C---~T Table 2 Rare sequence variants in the CFTR promoter and coding region Sequence variant Nucleotide change Location Frequency Associated mutatiow' Reference 125 G--+C G--~C at 125 Promoter 1 (0.1%) R75X F508C T--~G at 1655 Exon 10 2 (0.3%) S1251N 1716 G---)A G---~Aat 1716 Exon 10 1 (0.1%) L619S R553Q G-~A at 1790 Exon I 1 I (0.1%) * R668C C--~T at 2134 Exon 13 1 (0.1%) 3849+10 kB C--eT 3030 G---~A G--+A at 3030 Exon 15 1 (0.1%) 405+1 G--~A I1027 T T--~C at 3212 Exon 17a 2 (0.3%) * 3417 A-+T A--->Tat 3417 Exon 17b 1 (0.1%) Unknown 4002 A--eG A--~G at 4002 Exon 20 2 (0.3%) Unknown Cutting et al. (1992) Kobayashi et al. (1990) Kerem et al. (1990) D6rk et al. ( 1991) Fanen et al. (1992) Chillon et al. (1992) Fanen et al. (1992) This study Ferec et al. (1992) ~'Marked (*) sequence variations were present on AF508 chromosomes were the most frequent in pancreas-sufficient patients. 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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44 This mutation has previously been described as a "mild" mutation.24 As reported by Kalin et al,25 the two CF chromosomes (from unrelated patients) positive for S1251N also carry the polymorphism F508C,26 but two other CF chromosomes bearing F508C are negative for S1251N and have unknown mutations. Login to comment

[hide] Heterogeneity in the severity of cystic fibrosis a... Hum Genet. 1994 Apr;93(4):364-8. Dean M, Santis G
Heterogeneity in the severity of cystic fibrosis and the role of CFTR gene mutations.
Hum Genet. 1994 Apr;93(4):364-8., [PMID:7513291]

Abstract [show]
Cystic fibrosis is a common, fatal disorder caused by abnormalities in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CFTR encodes a chloride channel that regulates secretion in many exocrine tissues. The presentation of cystic fibrosis is highly variable as measured by the age of onset of disease, the presence of pancreatic insufficiency, or the progression of lung disease. Over 400 mutations in the CFTR gene have been described in cystic fibrosis patients and considerable effort has focused on the correlation between specific mutations and genotypes and clinical characteristics. Individual tissues display variation in their sensitivity to CFTR mutations. The vas deferens is functionally disrupted in nearly all males, whereas mild and severe pancreatic involvement is determined by the patient's genotype. The severity of pulmonary disease is poorly correlated with genotype, suggesting that there are other important genetic and/or environmental factors that contribute to lung infections and the subsequent disruption of lung function.

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87 Whether other missense alleles associated with CBAVD (D1270N, G576A, F508C) also encode for aberrant channel proteins remains to be determined. 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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164 However the S1251N mutation is associated with the F508C polymorphism which is, like M470V, located in exon 10 of the CFTR gene (5). Login to comment

[hide] A healthy male with compound and double heterozygo... Am J Hum Genet. 1994 Feb;54(2):384-5. Desgeorges M, Kjellberg P, Demaille J, Claustres M
A healthy male with compound and double heterozygosities for delta F508, F508C, and M47OV in exon 10 of the cystic fibrosis gene.
Am J Hum Genet. 1994 Feb;54(2):384-5., [PMID:7508183]

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9 Among them, the substitution of cysteine for phenylalanine 508, named "F508C" (Kobayashi et al. 1990) or 1655 T or G (Cystic Fibrosis Genetic Analysis Consortium, unpublished results), is ofparticular interest both because ofitsphysio- logical significance and because it can cause pitfalls in molecular diagnosis. Login to comment
10 Four other compound heterozygous persons AF508/F508C have been reported in this Journal (Kobayashi et al. 1990; Macek et al. 1992; Meschede et al. 1993). Login to comment
12 The case described here makes it unlikely that, as concluded by Meschede et al. (1993), the combined trans and cis configuration of AF508, F508C, and M470V could contribute to the CBAVD phenotype. Login to comment
13 AF508 AM508 A-'o0 AF508 A1507 AF508 F508C AF50O M470V Figure I Letters to the Editor MARIE DESGEORGES, PAULE KJELLBERG, JACQUES DEMAILLE, AND MIREILLE CLAUSTRES Laboratoire de Biochimie Genitique Institut de Biologie Montpellier Acknowledgment This work was supported by a grant from the French Association against Cystic Fibrosis (Association Franqaise contre la Mucoviscidose; AFLM). 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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114 Four F508C alleles were found in this study, which all turned out to carry the $1251N mutation and a second missense mutation polymorphism (M470V). Login to comment
113 Four F508C alleles were found in this study, which all turned out to carry the $1251N mutation and a second missense mutation polymorphism (M470V). Login to comment

[hide] Compound heterozygosity for the delta F508 and F50... Am J Hum Genet. 1993 Jul;53(1):292-3. Meschede D, Eigel A, Horst J, Nieschlag E
Compound heterozygosity for the delta F508 and F508C cystic fibrosis transmembrane conductance regulator (CFTR) mutations in a patient with congenital bilateral aplasia of the vas deferens.
Am J Hum Genet. 1993 Jul;53(1):292-3., [PMID:7686336]

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7 (1992) describe a peculiar pattern of heteroduplex formation in a case of compound heterozygosity for the AF508 and F508C mutations in the CFTR gene (cystic fibrosis transmembrane conductance regulator gene). Login to comment
16 Apart from a Table I CFTR Gene Haplotypes in the Patient and His Parents CFTR GENE HAPLOTYPE' MUTATION OR Father of Mother of POLYMORPHISM Patient Patient Patient AF508 ........ AF508/+ AF508/+ +/+ F508C ........ +/F508C +/+ +/F508C M470C ....... +/M470V +/+ +/M470V a A plus sign (+) denotes presence of the wild-type allele. Login to comment
19 Direct sequencing showed heterozygosity for the AF508 and F508C mutations and the amino acid polymorphism M470V (Kerem et al. 1990). Login to comment
23 In the mother, heterozygosity for the F508C mutation and the M470V polymorphism was detected. Login to comment
24 In the patient and his mother, F508C and M470V were present on the same chromosome (cis configuration), as can be deduced from the segregation pattern (table 1). Login to comment
25 Compound heterozygosity for AF508 and F508C has been reported in clinically normal individuals (Kobayashi et al. 1990; Macek et al. 1992), in patients with typical CF symptoms (Kerem et al. 1990), and now, for the first time, in a case of CBAVD. Login to comment
26 The basis for this wide clinical variability is unclear, as is the functional significance of the F508C mutation. Login to comment
28 It cannot be excluded, however, that this mutation contributes to the clinical phenotype of CBAVD if it is inherited together with AF508 and F508C. Login to comment
29 To further clarify this issue, we are currently screening a larger number of patients with congenital anomalies of the Wolffian-duct derivatives, for M470V and F508C mutations. Login to comment
35 Am J Hum Genet 47:611-615 Macek M Jr, Ladanyi L, Burger J, Reis A (1992) Missense variations in the cystic fibrosis gene: heteroduplex formation in the F508C mutation. Login to comment

[hide] Effects of the delta F508 mutation on the structur... J Bioenerg Biomembr. 1993 Feb;25(1):11-9. Thomas PJ, Pedersen PL
Effects of the delta F508 mutation on the structure, function, and folding of the first nucleotide-binding domain of CFTR.
J Bioenerg Biomembr. 1993 Feb;25(1):11-9., [PMID:7680027]

Abstract [show]
The fatal autosomal recessive disease cystic fibrosis (CF) is caused by mutations in the gene which encodes the cystic fibrosis transmembrane conductance regulator (CFTR). Many of these disease-causing mutations, including the deletion of F508 (delta F508) which accounts for approximately 70% of the disease alleles, occur in one of the two consensus nucleotide binding sequences. Peptide studies have directly demonstrated that the N-terminal nucleotide binding sequences bind adenine nucleotides. Structurally, circular dichroism spectropolarimetry indicates that this region of CFTR assumes a beta-stranded structure in solution. The delta F508 mutation causes a diminution in the amount of beta-stranded structure and a concomitant increase in the amount of random coil structure present, indicating that either the mutant peptide has a different native structure or that the conformational equilibrium is shifted toward a more disordered form. Furthermore, the mutant peptide is more sensitive to denaturation, indicating that delta F508 is a stability, or protein-folding mutant. Here we review these results and discuss their implications for interpreting the behavior of delta F508 in situ and for the rational design of new CF drugs.

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76 This proposal is supported by genetic evidence that the F508C mutation is benign (Kobayashi et al., 1990) and that the AI506/7 mutation causes CF (Kerem et al., 1990). Login to comment

[hide] Missense variations in the cystic fibrosis gene: h... Am J Hum Genet. 1992 Nov;51(5):1173-4. Macek M Jr, Ladanyi L, Burger J, Reis A
Missense variations in the cystic fibrosis gene: heteroduplex formation in the F508C mutation.
Am J Hum Genet. 1992 Nov;51(5):1173-4., [PMID:1384326]

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25 In theirpaper, two AF508 /F508C compound heterozygous individuals were reported. Login to comment
26 Clinical and epithelial physiological studies in both cases were normal, suggesting that the substitution of cysteine for phenylalanine at position 508, the F508C mutation, is benign. Login to comment
31 Subsequent direct sequencing ofthe PCR product confirmed that this clinically normal father is a compound heterozygote for the AF508 /F508C mutations. Login to comment
33 Since the pattern of the AF508/F508C heteroduplexwas notpublished, it is likelythat similar cases can be overseen during the widely performed AF508 mutation screening by PAGE. Login to comment
42 Lane 3 contains a PCR product from a AF508/F508C compound heterozygote individual with homoduplexes as in AF508 heterozygotes but with slightly different heteroduplexes. Login to comment

[hide] Development, multiplexing, and application of ARMS... Am J Hum Genet. 1992 Aug;51(2):251-62. Ferrie RM, Schwarz MJ, Robertson NH, Vaudin S, Super M, Malone G, Little S
Development, multiplexing, and application of ARMS tests for common mutations in the CFTR gene.
Am J Hum Genet. 1992 Aug;51(2):251-62., [PMID:1379414]

Abstract [show]
The amplification refractory mutation system (ARMS) is a simple, rapid and reliable method for the detection of any mutation involving single base changes or small deletions. We have applied ARMS methodology to the detection of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Single ARMS tests have been developed for 11 CFTR mutations found in the northwest of England. ARMS reactions for the most common mutations have been multiplexed to give a test which will detect the presence of the delta F508, G551D, G542X, and 621 + 1G----T mutations in a DNA sample. The multiplex test has been validated by the analysis of over 500 previously genotyped samples and has been found to be completely accurate. The rapid detection of the most common mutations has enabled early molecular confirmation of suspected cystic fibrosis in neonates, rapid typing of cystic fibrosis patients and their relatives, and testing of sperm and egg donors.

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82 The development of these ARMS tests was complicated by the existence of two additional benign mutations of the CFTR gene, namely F508C and 1506V (Kobayashi et al. 1990). Login to comment
88 DNA samples carrying the benign mutations were not available for analysis, but, as the 1506V mutation was proximal to the ARMS target site, and as the F508C mutation was complementary to the normal ARMS primer, it seems likely that samples containing either of these sequences would appear normal in this test. Login to comment
83 The development of these ARMS tests was complicated by the existence of two additional benign mutations of the CFTR gene, namely F508C and 1506V (Kobayashi et al. 1990). Login to comment
89 DNA samples carrying the benign mutations were not available for analysis, but, as the 1506V mutation was proximal to the ARMS target site, and as the F508C mutation was complementary to the normal ARMS primer, it seems likely that samples containing either of these sequences would appear normal in this test. 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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135 The finding that substitution of Phe508 with cysteine or I1e506 with valine does not cause CF (41) supports the conclusion that proper spacing in this region is more important than the type of amino acid at certain locations (20). 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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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
104 Four mutations, R347P, F508C, Rl162X, and 3659delC were found to be linked with the most common haplotype, whereas five mutations were identified on the second most frequent haplotype. 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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27 The patients and their families were referred to us from six Table 1 Listing of the CFTR mutations which are interrogated in the CF assay used in this study Mutation Location Mutation Location Exon/Intron Exon/Intron DF508 E.10 W1282X E.20 F508C E.10 3905insT E.20 DI507 E.10 N1303K E.21 Q493X E.10 G85E E.3 V520F E.10 621 + 1G ! 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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47 If indicated, testing includes reflex analysis for the following variants: 5/7/9T exon 9 splice acceptor tracts, F508C, I507V and I506V. 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] 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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70 Group A Group B Group C Group D Classic-CF CF-causing mutations Non-classic CF CFTR-related disorder associated mutations No clinical consequence Unknown clinical relevance All mutations in Table 2 and 711 + 3A > G*, R117H-T5*, D1152H*, L206W*, TG13-T5* TG13-T5a , R117H-T5a , D1152Ha , L206Wa , L997F, M952I, D565Ga , TG11-T5b , R117H-T7b , D443Y-G576A-R668C, R74W-D1270N, R75Qb TG11-T5b , R117H-T7b , R75Qb , 875 + 40A/G, M470V, T854T, P1290P, I807M, I521F, R74W, F508C, I506V, I148T All mutations (mostly missense) not yet analyzed or undergoing functional analysis a Mutations that may belong either to Group A or to Group B. b Mutations that may belong either to Group B or to Group C. 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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116 CFTR variant %Cases %Uctrls OR p-value %Cases w/N34S OR w/N34S p-value w/N34S F508C 0.5 0.3 1.58 0.21 0.0 0.00 0.67 R1162L 0.5 0.5 1.13 0.29 1.8 4.03 0.17 I1027T 0.5 0.3 1.99 0.17 0.0 0.00 0.70 R31C 0.3 0.7 0.42 0.088 0.0 0.00 0.52 I148T 0.3 0.4 0.75 0.27 0.0 0.00 0.63 R297Q 0.3 0.2 1.89 0.21 0.0 0.00 0.76 R74W 0.2 0.2 0.85 0.29 0.0 0.00 0.71 F1052V 0.1 0.2 0.63 0.27 0.0 0.00 0.76 I807M 0.1 0.1 1.26 0.30 0.0 0.00 0.83 R258G 0.1 0.1 1.26 0.30 0.0 0.00 0.83 G1069R 0.1 0.0 0.13 0.0 V201M 0.0 0.1 0.17 0.0 0.00 0.83 Of the 81 CFTR mutations tested in the cohort, 43 were observed at least once in cases or controls. Login to comment
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] 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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308 Of note, a perfect theoretical disulfide bridge in the double mutant F508C/Y1073C should be possible in this particular conformer [Online Resource 21 (B)]. Login to comment
309 The existence of the alternative position of F508 was further supported by the fact that the modification of F508C by benzyl-methanethiosulfonate (MTSBn), conserving the F508 aromatic character and restoring gating activity (lost for the F508C mutation in the open state-locked E1371S variant) [76], can be accommodated in both the initial and MD-generated models of CFTR [Online Resource 21 (A)]. Login to comment

[hide] Analysis of cystic fibrosis gene mutations in chil... J Med Case Rep. 2014 Oct 10;8:339. doi: 10.1186/1752-1947-8-339. Dell'Edera D, Benedetto M, Gadaleta G, Carone D, Salvatore D, Angione A, Gallo M, Milo M, Pisaturo ML, Di Pierro G, Mazzone E, Epifania AA
Analysis of cystic fibrosis gene mutations in children with cystic fibrosis and in 964 infertile couples within the region of Basilicata, Italy: a research study.
J Med Case Rep. 2014 Oct 10;8:339. doi: 10.1186/1752-1947-8-339., [PMID:25304080]

Abstract [show]
INTRODUCTION: Cystic fibrosis is the most common autosomal recessive genetic disease in the Caucasian population. Extending knowledge about the molecular pathology on the one hand allows better delineation of the mutations in the CFTR gene and the other to dramatically increase the predictive power of molecular testing. METHODS: This study reports the results of a molecular screening of cystic fibrosis using DNA samples of patients enrolled from January 2009 to December 2013. Patients were referred to our laboratory for cystic fibrosis screening for infertile couples. In addition, we identified the gene mutations present in 76 patients affected by cystic fibrosis in the pediatric population of Basilicata. RESULTS: In the 964 infertile couples examined, 132 subjects (69 women and 63 men) resulted heterozygous for one of the CFTR mutations, with a recurrence of carriers of 6.85%. The recurrence of carriers in infertile couples is significantly higher from the hypothetical value of the general population (4%). CONCLUSIONS: This study shows that in the Basilicata region of Italy the CFTR phenotype is caused by a small number of mutations. Our aim is to develop a kit able to detect not less than 96% of CTFR gene mutations so that the relative risk for screened couples is superimposable with respect to the general population.

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59 As mentioned before, molecular screening Table 2 Comparison between the results obtained in this study and those obtained in a previous study Castaldo et al. [14] Mutations observed in the present study F508del 55.8% (29) 48.62% (141) N1303K 3.8% (2) 9.31% (27) G542X 3.8% (2) 8.96% (26) W1282X 3.8% (2) 1.03% (3) 2183AA>G 5.8% (3) 2.76% (8) R1162X 0 0 1717-1G>A 1.9% (1) 0 T338I 0 0 R347P 0 0.69% (2) 711+5G>A 0 0 852del22 5.8% (3) 1.03% (3) 4382delA 0 0.69% (2) 1259insA 0 0.34% (1) 4016insT 0 0.34% (1) R553X 0 0.34% (1) R1158X 0 0 L1077P 0 1.03% (3) I502T 0 0 3849+10kbC>T 1.9% (1) 0.34% (1) D579G 0 0.69% (2) G1244E 3.8% (2) 0 G1349D 0 0.34% (1) 2789+5G>A 0 1.03% (3) 711+1G>T 0 0 L1065P 0 0 2522insC 0 0 E585X 0 0 G85E 0 0 G178R 0 0 D1152H 0 3.10% (9) I148T-3195del6 0 0 I148T (alone) 0 4.48% (13) R334W 0 0 DI507 0 0.69% (2) I1005R 0 0 3272-26A>G 0 0 2711delT 0 0 L558S 1.9% (1) 0.34% (1) W1063X 0 0 D110H 0 0 S549R (A>C) 1.9% (1) 0.69% (2) 2184insA 0 0 3131del22 0 0 Table 2 Comparison between the results obtained in this study and those obtained in a previous study (Continued) R709N 0 0 A349V 0 0 4015insA 0 0 Y849X 1.9% (1) 0.34% (1) G551D 0 1.03% (3) 621+3A>G 0 0.34% (1) E831X 0 0 I507del 0 0.69% (2) IVS8 TG12/t5 0 1.03% (3) H139R (A->G) 0 0.34% (1) 1248+1G>A 0 0.34% (1) R74W;V201M;D1270N 0 0.69% (2) S1455X 0 0.34% (1) dele 2,3 (21kb) 0 0.34% (1) 991del5 0 0.34% (1) UNKNOWN 7 %(4) 4.83% (14) F508C 0 0.69% (2) TOTAL 52 290 of CF is highly recommended in the USA by the National Institutes of Health Consensus Development Conference Statement on genetic testing for cystic fibrosis [17]. Login to comment
79 The test has a sensitivity and a specificity of more than Table 3 List of 60 mutations in the cystic fibrosis transmembrane regulator gene (specificity 100%) F508del I507del F508C 621+1G>T D110H E585X G1349D I502T 1706del17 1677delTA R117H H139R 1898+1G>A 4015delA G542X 1717-1G>A Q552X 852del22 G178R 1898+3A>G G551D S549R(A>C) 2183AA>G T338I 991del5 1898+5G>T N1303K 4016insT 3849+10kb C>T R347P R334W 2184insA G85E 711+5G>A 711+1G>T 1259insA R347H 2522insC 2789+5G>A W1282X G1244E R1066H R352Q 3120+1G>A I148T 3199del6 S912X R1158X 1717-8G>A R1066C R1162X 4382delA D1152H L1077P D579G 3272-26A>G L1065P R553X PoliT: 5T, 7T, 9T 1874insT 3659delC 99%. Login to comment

[hide] Mutation analysis of PRSS1, SPINK1 and CFTR gene i... Turk J Gastroenterol. 2015 Mar;26(2):176-80. doi: 10.5152/tjg.2015.4287. Sisman G, Tugcu M, Ayla K, Sebati O, Senturk H
Mutation analysis of PRSS1, SPINK1 and CFTR gene in patients with alcoholic and idiopathic chronic pancreatitis: A single center study.
Turk J Gastroenterol. 2015 Mar;26(2):176-80. doi: 10.5152/tjg.2015.4287., [PMID:25835118]

Abstract [show]
BACKGROUND/AIMS: A relation between some genetic mutations and chronic pancreatitis (CP) has been reported. However, the relation of genetic mutation to alcoholic CP (ACP) and idiopathic CP (ICP) still remains controversial. In this study, we investigated the prevalence of protease serine 1 (PRSS1), serine protease inhibitor, Kazal type 1 (SPINK1) SPINK1 and cystic fibrosis transmembrane conductance regulator (CFTR) mutations in ACP and ICP patients in Turkey. MATERIALS AND METHODS: Forty-one patients with ACP and 38 patients with ICP were enrolled, and 35 healthy individuals served as controls. The PRSS1 and SPINK1 mutations were investigated by the polymerase chain reaction (PCR)-restriction fragment-length polymorphism (RFLP) technique. The CFTR mutation was examined with PCR direct sequencing. RESULTS: The mean ages of the ACP, ICP and healthy control groups were 53.2, 40.4 and 46.3 years, respectively. A CFTR F508 mutation was detected as a heterozygote in one (2.4%) patient with ACP. In the ICP and control populations, PRSS1, SPINK1 and CFTR mutations were not detected. CONCLUSION: This study shows that PRSS1, SPINK1 and CFTR mutations do not play a role in ACP and ICP patients.

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45 DNA samples were multiplied by multiplex PCR with a CF 22Mut and CF 14Mut+Tn strip assay kit which has 36 common mutations of the CFTR gene (DF508, DI507, F508C, I502T, 1706del17, 1677del TA, G542X, 1717-1G>A, R553X, Q552X, G551D, S549R(A>C), N1303K, 4016insT, R1162X, R1158X, W1282X, G1244E, 2789+5G>A, 2183AA>G, 711+5G>A, 711+1G>T, G85E, 3849+10kbC>T, 621+1G>T, R117H, D1152H, L1065P, R1066H, L1077P, 4382delA, 1259insA, 852del22, R347P, T338I, S912X and Allele5T-7T-9T). 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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76 For example, inability to confirm the variants in both parents may be found in cases with apparent homozygosity for a common or a rare variant: Nonpaternity Presence on the opposite allele of a large deletion, nonrevealed by routine tests Presence of a rare SNP in primer-binding sites or a rare DNA variant that causes failure of amplification and/or hybridization of a probe: for example, false homozygosity for p.Phe508del due to the presence of the variant F508C (c.1523T4G); false homozygosity for p.Ile507del due to the presence of p.Ile507Val (I597V) (c.1519A4G). Login to comment