ABCMdb

ABCC7 p.Gly576Ala

ClinVar:	c.1727G>C , p.Gly576Ala ? , Conflicting interpretations of pathogenicity, not provided c.1726G>T , p.Gly576* ? , not provided
CF databases:	c.1727G>C , p.Gly576Ala N , Non CF-causing ; CFTR1: The mutation was detected by DGGE analysis and identified by direct DNA sequencing. The mutation was seen in a 45 year-old male with absence of the vas deferens, who also has [delta]F508. We have seen it only once, in over 100 non-[delta]F508 chromosomes screened, in this man referred by the Oxford Medical Genetics Laboratories (UK). The DGGE primers were generously supplied by Prof. Michel Goossens on behalf of the European Community Concerned Action for the Co-ordination of Cystic Fibrosis Research and Therapy.
Predicted by SNAP2:	A: D (80%), C: D (91%), D: D (95%), E: D (95%), F: D (95%), H: D (95%), I: D (95%), K: D (95%), L: D (95%), M: D (95%), N: D (95%), P: D (91%), Q: D (95%), R: D (95%), S: D (53%), T: D (75%), V: D (95%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	A: N, C: N, D: N, E: N, F: D, H: N, I: D, K: N, L: D, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, 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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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

[hide] A new approach for identifying non-pathogenic muta... Hum Genet. 2000 Feb;106(2):172-8. Bombieri C, Giorgi S, Carles S, de Cid R, Belpinati F, Tandoi C, Pallares-Ruiz N, Lazaro C, Ciminelli BM, Romey MC, Casals T, Pompei F, Gandini G, Claustres M, Estivill X, Pignatti PF, Modiano G
A new approach for identifying non-pathogenic mutations. An analysis of the cystic fibrosis transmembrane regulator gene in normal individuals.
Hum Genet. 2000 Feb;106(2):172-8., [PMID:10746558]

Abstract [show]
Given q as the global frequency of the alleles causing a disease, any allele with a frequency higher than q minus the cumulative frequency of the previously known disease-causing mutations (threshold) cannot be the cause of that disease. This principle was applied to the analysis of cystic fibrosis transmembrane conductance regulator (CFTR) mutations in order to decide whether they are the cause of cystic fibrosis. A total of 191 DNA samples from random individuals from Italy, France, and Spain were investigated by DGGE (denaturing gradient gel electrophoresis) analysis of all the coding and proximal non-coding regions of the gene. The mutations detected by DGGE were identified by sequencing. The sample size was sufficient to select essentially all mutations with a frequency of at least 0.01. A total of 46 mutations was detected, 20 of which were missense mutations. Four new mutations were identified: 1341+28 C/T, 2082 C/T, L1096R, and I11131V. Thirteen mutations (125 G/C, 875+40 A/G, TTGAn, IVS8-6 5T, IVS8-6 9T, 1525-61 A/G, M470V, 2694 T/G, 3061-65 C/A, 4002 A/G, 4521 G/A, IVS8 TG10, IVS8 TG12) were classified as non-CF-causing alleles on the basis of their frequency. The remaining mutations have a cumulative frequency far exceeding q; therefore, most of them cannot be CF-causing mutations. This is the first random survey capable of detecting all the polymorphisms of the coding sequence of a gene.

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79 Out of the 20 missense mutations, three (G85E, ∆F508, and N1303K) are certainly CF-causing, and several (R31C, K68E, R75Q, I148T, V562L, G576A-R668C, L997F, F1052V, S1235R) have been described in congenital bilateral absence of the vas deferens, in disseminated bronchiectasis, in pancreatitis, or in atypical CF cases mutations as reported in the CFGAC website (). Login to comment
80 Many (13 out of 20) of the missense mutations change highly conserved (5/5 species analyzed) amino acid residues (R75Q, G85E, I148T, I506V, R668C, G622D, L997F, I1027T, F1052V, L1096R, I1131V, R1162L, N1303K); others affect amino acid residues conserved in 4/5 species (K68 E, R170H, M470V, V562L, S1235R), or in 3/5 species (R31C and G576A; Tucker et al. 1992). Login to comment
86 In addition to very common mutations, which are often associated with other mutations in the same gene, two sporadic mutations were found together in the same individual (G576A and R668C once; 3041-71 G/C and 4002 A/G twice) in three cases. Login to comment
96 Moreover, 1525-61 A/G (i 9) and 3601-65 C/A (i 18) were detected by SSCA performed in the Spanish sample only (14/82 and 12/80, respectively); these mutations were not identifiable by DGGE as used in the present work The totals are: a378; b362; c380; d356 genes eCertainly a CF-causing mutations fThe most common allele at this site is (TTGA)7 gThe most common allele at this site is T7 hThe frequency shown is that of the M allele Mutation Position North-Central Southern Spain Total East Italy Italy France 82 genes 100 genes 100 genes 100 genes 382 genes % 125 G/C 5`UTR 1 2 7 3 13 3.4 R31C 2 1 1 1 0 3 0.8 K68E 3 1 0 0 0 1 0.3 R75Q 3 1 1 2 0 4 1.0 G85Ee 3 0 1 0 0 1 0.3 406-6 T/C i 3 0 0 1 0 1 0.3 I148T 4 1 0 0 0 1 0.3 621+3 A/G i 4 0 1 0 0 1 0.3 R170H 5 1 0 0 0 1 0.3 875+40 A/G i 6a 11 5 5 2 23 6.0 (TTGA)6 f i 6a 17 11 7 13 48 12.6 1341+28 C/T i 8 1 0 0 0 1 0.3 IVS8-6g T5 i 8 8 2 4 3/78 17a 4.5 IVS8-6g T9 i 8 10 7 10 11/78 38a 10.0 M470Vh 10 42 30 39 27 138 36.1 I506V 10 1 0 0 0 1 0.3 ∆F508e 10 1 0 2 0 3 0.8 1716 G/A 10 2 1 0 5 8 2.1 V562L 12 0 0 1 0 1 0.3 G576A 12 1 0/80 1 0 2b 0.6 G622D 13 0 0/80 1 0 1b 0.3 R668C 13 1 0/80 1 0 2b 0.6 2082 C/T 13 1 0/80 0 0 1b 0.3 2377 C/T 13 0 0/80 0 1 1b 0.3 2694 T/G i 14a 33 23 33 14/80 103c 27.1 2752-15 C/G i 14b 0 3 0 0 3 0.8 3041-71 G/C i 15 0 1 2 0 3 0.8 L997F 17a 0 2 0 0 2 0.5 I1027T 17a 1 0 0 0 1 0.3 F1052V 17b 1 0 0 0 1 0.3 L1096R 17b 0 0 1 0 1 0.3 3417 A/T 17b 1 0 1 0 2 0.5 I1131V 18 0 1 0 0 1 0.3 R1162L 19 0 1 0 0 1 0.3 3690 A/G 19 0 0 0 1/80 1c 0.3 S1235R 19 1 0 0 0 1 0.3 4002 A/G 20 2 3 3 3/80 11c 2.9 4005+28insA i 20 0 1 0 0 0.3 4029 A/G 21 1 0 0 0 1 0.3 N1303Ke 21 1 0 0 0 1 0.3 4404 C/T 24 1 0 1 0 2 0.5 4521 G/A 24 21 16 14/80 15/76 66d 18.5 Total 165 113 137 98 513 encountered in the present survey are possible. Login to comment
115 The density of polymorphic sites, which is essentially the proportion of sites susceptible to evolving among the total number of sites (bp) of that gene, can be estimated by counting the number n of polymorphic sites existing in 177 Table 4 A list of the 13 ED-C mutations detected in this survey Mutation q±SE q-2.5SE 125 G/C 0.0340±0.0093 0.011 875+40 A/G 0.0602±0.0122 0.030 876-5 (GATT)6 0.1257±0.0170 0.083 IVS8 T5 0.0450±0.0107 0.018 IVS8 T9 0.1005±0.0155 0.062 IVS8 (TG)10 0.2900±0.0262 0.223 IVS8 (TG)12 0.0867±0.0162 0.046 1525-61 A/Ga 0.1750±0.0420 0.070 M470V 0.3613±0.0246 0.300 2694 T/G 0.2711±0.0228 0.214 3601-65 C/Aa 0.1500±0.0399 0.050 4002 A/G 0.0289±0.0086 0.007 4521 G/A 0.1854±0.0206 0.134 aSearched by SSCA in the sample of 40 Spanish individuals only: frequency and standard error are those of that sample Table 5 Distribution in the four subsamples of mutations found a few times but not classified Total number of Subsample times the mutation has been found NE Italy Central Southern Spain Italy France Twice G576A 1 - 1 - R668C 1 - 1 - L997F - 2 - - 3417 A/T 1 - 1 - 4404 C/T 1 - 1 - Three times R31C 1 1 1 - 2752-15 C/G - 3 - - 3041-71 G/C - 1 - Four times R75Q 1 1 2 - Eight times 1716 G/Aa 2 1 - 5 aGiven its frequency and distribution, this mutant will probably turn out to be a C mutant the stretch under study of N bp and dividing n by N. Usually, the number of sites identified as polymorphic sites is merely a minimum estimate of the total number n of polymorphic sites of the N stretch, because the number of polymorphic sites of the stretch that escaped detection remains unknown. Login to comment

[hide] Heterogeneity for mutations in the CFTR gene and c... Hum Reprod. 2000 Jul;15(7):1476-83. Casals T, Bassas L, Egozcue S, Ramos MD, Gimenez J, Segura A, Garcia F, Carrera M, Larriba S, Sarquella J, Estivill X
Heterogeneity for mutations in the CFTR gene and clinical correlations in patients with congenital absence of the vas deferens.
Hum Reprod. 2000 Jul;15(7):1476-83., [PMID:10875853]

Abstract [show]
Congenital absence of the vas deferens (CAVD) is a heterogeneous disorder, largely due to mutations in the cystic fibrosis (CFTR) gene. Patients with unilateral absence of the vas deferens (CUAVD) and patients with CAVD in association with renal agenesis appear to have a different aetiology to those with isolated CAVD. We have studied 134 Spanish CAVD patients [110 congenital bilateral absence of the vas deferens (CBAVD) and 24 CUAVD], 16 of whom (six CBAVD, 10 CUAVD) had additional renal anomalies. Forty-two different CFTR mutations were identified, seven of them being novel. Some 45% of the CFTR mutations were specific to CAVD, and were not found in patients with cystic fibrosis or in the general Spanish population. CFTR mutations were detected in 85% of CBAVD patients and in 38% of those with CUAVD. Among those patients with renal anomalies, 31% carried one CFTR mutation. Anomalies in seminal vesicles and ejaculatory ducts were common in patients with CAVD. The prevalence of cryptorchidism and inguinal hernia appeared to be increased in CAVD patients, as well as nasal pathology and frequent respiratory infections. This study confirms the molecular heterogeneity of CFTR mutations in CAVD, and emphasizes the importance of an extensive CFTR analysis in these patients. In contrast with previous studies, this report suggests that CFTR might have a role in urogenital anomalies.

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71 Six polymorphisms: 125G/C, 1525-61A/G, L206W 9 (6) 0 9 (5) 1898ϩ152T/A, 1716G/A, G576A and 875ϩ40A/G presented R117H 8 (5) 0 8 (5) frequencies of between 2.5% and 4.0%. Login to comment

[hide] Fetal bowel hyperechogenicity may indicate mild at... J Med Genet. 2000 Aug;37(8):E15. Abramowicz MJ, Dessars B, Sevens C, Goossens M, Girodon-Boulandet E
Fetal bowel hyperechogenicity may indicate mild atypical cystic fibrosis: a case associated with a complex CFTR allele.
J Med Genet. 2000 Aug;37(8):E15., [PMID:10922395]

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18 CFTR gene studies were pursued using a DGGE scanning strategy,8 9 and the maternal CFTR allele was found to carry three missense mutations, D443Y (1459G>T, exon 9), G576A (1859G>C, exon 12), and R668C (2134C>T exon 13), which have each previously been reported in males with CBAVD.10-12 On further analysis, the complex mutated maternal allele was found in the younger boy. Login to comment
25 The two brothers and fetus are compound heterozygotes for the N1303K mutation and the complex CFTR allele D443Y-G576A-R668C. Login to comment
29 N1303K N D443Y G576A R668C N D443Y G576A R668C N1303K D443Y G576A R668C N1303K D443Y G576A R668C N1303K Electronic letter of 3 www.jmedgenet.com a regular basis and propose the following approach. Login to comment
39 D443Y, G576A, and R668C have been observed independently or in pairs, in patients with a CF related syndrome for whom the whole CFTR coding sequence has been analysed: D443Y, G576A, R668C, D443Y-G576A, D443Y-R668C in CBAVD patients10-12 and G576A-R668C in a patient with disseminated bronchiectasis, but with no other CF causing mutation found in trans.15 To our knowledge, the D443Y mutation was only observed in CBAVD patients.11 12 The G576A and R668C variations have both initially been described as polymorphisms since they were found on the non-CF chromosome of the mother of a CF child.8 However, they were later considered as putative mild mutations associated with a CBAVD phenotype when combined in trans with F508.16 17 These genotypes may possibly not be disease causing in women. Login to comment
45 In another fetus with FBH at 21 weeks` gestation, we found the genotype W846X/G576A-R668C. Login to comment
48 It is thus possible that, in our family, the D443Y variation worsens a very mild deleterious eVect of the G576A-R668C allele, or vice versa, accounting for the abnormal sweat test and, perhaps, the respiratory infections in the younger brother. Login to comment

[hide] CFTR and asthma in the French EGEA study. Eur J Hum Genet. 2001 Jan;9(1):67-9. de Cid R, Chomel JC, Lazaro C, Sunyer J, Baudis M, Casals T, Le Moual N, Kitzis A, Feingold J, Anto J, Estivill X, Kauffmann F
CFTR and asthma in the French EGEA study.
Eur J Hum Genet. 2001 Jan;9(1):67-9., [PMID:11175304]

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1 Results regarding ∆F508 come from a Danish study conducted in about 9000 subjects from the general population.1 However, the hypothesis that ∆F508 heterozygosity in the CFTR gene could protect against asthma, was proposed earlier after a study conducted in obligate heterozygotes.3 Recently, a case control study based on 144 asthmatics recruited in emergency rooms in Barcelona and a first control group of 41 spouses of CF carriers showed an excess of heterozygotes for aminoacid variants in the asthmatics, R75Q, G576A, R668C and L997F being the most frequent. Login to comment
8 Due to the work load, only the four most common variants previously observed in asthmatics (R75Q, G576A, R668C and L997F), which accounted for 50% of mutations in asthmatics in the Barcelona study, were typed in the EGEA study as previously in the second control group in Barcelona, using the same techniques.2 The most common mutation in cystic fibrosis, ∆F508 was analysed by acrylamide gel electrophoresis, and the missense variant M470V8 was analysed by DGGE. Login to comment
10 Three missense variants R75Q,10 G576A,11 L997F11 were analyzed by restriction analysis. Login to comment
11 Variant R668C11 was analyzed by SSC A. Prevalences in the whole sample of 480 subjects were 2.9%, 3.8%, 4.0%, 4.2% and 0.6% for heterozygosity for ∆F508, R75Q, G576A, R668C and L997F, respectively. Login to comment
18 Any variant (R75Q, R668C, G576A, L997F), carriers of M allele (M470V), or 5T/-, shows odds ratios lower than 1, which were not statistically significant, except for 5T/-. Login to comment
35 Although differences in population could explain the differences between asthmatics in Barcelona and in France, the most likely hypothesis is that the four variants which were unusually frequent in the asthmatics in the first study do not relate to asthma, since a similar distribution to that of Table 1 Comparison of cases and controls from the EGEA study Controls: no asthma P value Asthma cases Both parents: no asthma OR [95% CI] Number 247 174 Demographic and clinical characteristics Geographical origin within France Paris, % 24.9 25.8 0.98 North West, % 11.0 9.8 South West, % 5.3 4.6 North East, % 6.9 8.1 South East, % 51.8 51.7 Age, m±SD 30.2±17.9 34.7±16.1 0.01 [range] [7.0-68.8] [7.4-64.7] Sex, % males 57.1 49.4 0.12 Atopy (weal ≥ 3mm, any of 11 allergens), % 76.8 34.8 0.001 6.4 [4.2-9.7] IgE, IU/ml, GM 246 36 0.001 Hay fever or childhood eczema, % 61.4 30.5 0.001 3.6 [2.4-5.5] FEV1 % predicted, m±SD 0.88±0.19 1.04±0.15 0.001 FVC % predicted, m±SD 0.99±0.16 1.04±0.15 0.001 Methacholine challenge, numbera 113 127 PD20 ≤ 4mg, % 92.9 22.8 0.001 44.4 [22.4-87.8] CFTR data ∆F508, % 3.2 2.9 0.83 1.13 [0.36-3.52] R75Q, % 2.4 5.2 0.14 0.46 [0.16-1.28] G576A, % 3.6 4.0 0.84 0.90 [0.33-2.47] R668C, % 3.6 4.6 0.62 0.79 [0.30-2.07] L997F, % 0.4 0.6 1.0b R75Q or G576A or R668C or L997F, % 6.9 9.8 0.28 0.68 [0.34-1.37] M470V MM, % 18.2 17.2 MV, % 46.2 50.6 0.66 VV, % 35.6 32.2 IVS8-(T) n, 5T/-, % 6.9 12.6 0.05 0.51 [0.27-0.99] a FEV1 > 80% predicted and no contraindications. Login to comment

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

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

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47 Three subjects were found to be heterozygotes, carriers of a single mutation (⌬F508, L165S, and G576A). Login to comment

[hide] Prenatal detection of cystic fibrosis by ultrasono... J Med Genet. 2002 Jun;39(6):443-8. Scotet V, De Braekeleer M, Audrezet MP, Quere I, Mercier B, Dugueperoux I, Andrieux J, Blayau M, Ferec C
Prenatal detection of cystic fibrosis by ultrasonography: a retrospective study of more than 346 000 pregnancies.
J Med Genet. 2002 Jun;39(6):443-8., [PMID:12070257]

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241 However, they based their comparison on an expected carrier rate in the general population which appears to be overestimated.1 The CFTR mutations identified in fetuses with echogenic bowel that have been reported so far are associated with pancreatic insufficiency (for example, ∆F508, G542X, G551D, Table 2 Ability of the ultrasound examination to detect cystic fibrosis Cystic fibrosis TotalYes No Utrasound examination Abnormal 14 128 142 Normal 112 346 300 346 412 Total 126 346 428 346 554 2183AA→G, ∆F311).9 13 27 43 To our knowledge, only one mutation associated with a mild phenotype (R117H)13 and one mild complex CFTR allele (D443Y-G576A-R668C)44 have been identified in two of the CF affected fetuses. Login to comment

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

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

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71 In the last case (21) the fetus carried the nonsense mutation W846X (detected in the first step using DGGE), associated with the complex allele G576A-R668C. Login to comment
73 Fetuses Carrying Two CFTR Mutations Cases CFTR Gene Mutations Ultrasound Findings Outcome 1-9 DF508/DF508 Hyperechogenic bowel TOP 10,11 DF508/DF508 Hyperechogenic bowel þ dilated loop TOP 12 DF508/DF508 Hyperechogenic bowel þ dilated loop þ gall bladder not seen TOP 13 DF508/DF508 Hyperechogenic bowel þ gall bladder not seen TOP 14 DF508/DF508 Intestinal dilated loops (absent at 22 wks) Birth, CF-affected, meconium ileus at birth 15 DF508/W1282X Hyperechogenic bowel (absent at 22 wks) TOP 16 DF508/G542X Hyperechogenic bowel þ dilated loop TOP 17 DF508/1078delT Hyperechogenic bowel þ dilated loop (absent at 22 wks) Birth, CF-affected,* meconium ileus at birth 18 DF508/O220X Hyperechogenic bowel þ dilated loop (present at 33 wks) Birth, CF-affected,* meconium ileus at birth 19 1078delT/394delTT Hyperechogenic bowel TOP 20** CFTRdele19/CFTRdele19 Hyperechogenic bowel (present at 33 wks) Birth, CF-affected, absence of meconium ileus at birth 21 W846X/G576A-R668C Hyperechogenic bowel Birth, potential absence of vas deferens TOP ¼ termination of pregnancy; Wks ¼ weeks of amenorrhea. Login to comment

[hide] New type of disease causing mutations: the example... Hum Mol Genet. 2003 May 15;12(10):1111-20. Pagani F, Stuani C, Tzetis M, Kanavakis E, Efthymiadou A, Doudounakis S, Casals T, Baralle FE
New type of disease causing mutations: the example of the composite exonic regulatory elements of splicing in CFTR exon 12.
Hum Mol Genet. 2003 May 15;12(10):1111-20., 2003-05-15 [PMID:12719375]

Abstract [show]
The increase in genome scanning data, derived from clinical genetics practice, is producing a wealth of information on human sequence variability. The critical issue is to identify if a given nucleotide change results in a benign polymorphism or a disease-causing mutation. We have focused on one specific gene expression step, pre-mRNA processing, where we can functionally define the effect of nucleotide changes and in turn the patient's mutation can shed light on the basic pre mRNA splicing mechanisms. Our results show that several nucleotide changes in CFTR exon 12 induce a variable extent of exon skipping that leads to reduced levels of normal transcripts. This is the case in both natural mutations D565G and G576A (the latter having previously considered a neutral polymorphism) and several site-directed silent substitutions. We demonstrate here that this phenomenon is due to the interference with a new regulatory element that we have named composite exonic regulatory element of splicing (CERES). The effect of single nucleotide substitutions at CERES cannot be predicted by neither SR matrices nor enhancer identification. The recognition and characterization of splicing abnormalities, caused by exon sequence variations at CERES elements, may represent a frequent disease-causing mechanism that also relates to the phenotypic variability. Our results indicate that even the most benign looking polymorphism in an exon cannot be ignored as it may affect the splicing process. Hence, appropriate functional splicing assays should be included in genotype screenings to distinguish between polymorphisms and pathogenic mutations.

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4 This is the case in both natural mutations D565G and G576A (the latter having previously considered a neutral polymorphism) and several site-directed silent substitutions. Login to comment
29 This is the case for two interesting and enigmatic missense mutations, D565G and G576A. Login to comment
31 The conservative G576A missense substitution was originally listed as a neutral polymorphism in the Cystic Fibrosis Genetic Analysis Consortium (http://genet.sickkids.on.ca). Login to comment
38 Mutations inducing exon skipping include both missense D565G and G576A mutants and several neutral substitutions. Login to comment
40 RESULTS D565G and G576A missense mutations cause CFTR exon 12 skipping in vivo We evaluated, in nasal epithelial cells, the pattern of CFTR exon 12 splicing in both normal subjects and heterozygous individuals with D565G and G576A alleles. Login to comment
43 The patient carrying the G576A missense mutation was affected by testicular azoospermia and in this case the G576A allele was also in cis with the R668C polymorphism. Login to comment
46 Two PCR`s were set up for the nasal epithelial cell cDNA derived from each of the D565G and G576A heterozygotes and from heterozygous controls for R668C, using the common F3 forward primer in exon 11 and each of the two allele specific primers of exon 13 (Fig. 1A). Login to comment
48 In heterozygous individuals the 668C allele carrying the mutations D565G or G576A clearly showed a significantly lower proportion of normal transcripts containing exon 12 than the 668R allele (Fig. 1B, lanes 7-20). Login to comment
53 This analysis showed that the mutant D565G and G576A alleles produced about 40 and 22% of exon inclusion, respectively (Table 1). Login to comment
54 These results indicate that, in nasal epithelial cells, the D565G and G576A missense mutations cause a splicing defect affecting the recognition of CFTR exon 12. Login to comment
55 Defective CFTR exon 12 recognition in hybrid minigenes containing D565G and G576A missense mutations In order to study in more detail the splicing regulation of CFTR exon 12 we have developed a faithful splicing assay that mimics the in vivo situation. Login to comment
61 Allele-specific PCR transcript analysis F3/668R F3/668C Subjects with D565G mutation 89.7Æ 5.9 40Æ 8.3a Subject with G576A mutation 88Æ 3 22Æ 4b Normal controls (heterozygotes for polymorphism R668C) 91.7Æ 5.1 89.3Æ 8.1 Data from six subjects with the D565G mutation, one patient with the G576A mutation and four controls are calculated from the experimental proportions of CFTR exon 12 inclusion adjusted according to the graph shown in Figure 1C. Login to comment
63 a Transcripts containing exon 12 derived from the D565G allele. b Transcripts containing exon 12 derived from the G576A allele. Login to comment
65 RT-PCR allele-specific amplification experiments in D565G and G576A carriers. Login to comment
67 The position of the missense substitutions (D565G and G576A) in exon 12 and of the C668R polymorphic variant in exon 13 is indicated. Login to comment
70 The D565G and G576A carriers presented the missense mutation in cis with the 668C variant. Login to comment
72 RNA extracted from nasal epithelial cells from R688C heterozygous controls (lanes 1-6), from D565G carriers (lanes 7-18) and from the G576A carrier (lanes 19-20), was reverse transcribed and amplified with F3/668C primers (even-numbered lanes) and with F3/668R primers (odd-numbered lanes). Login to comment
89 We then studied the pattern of splicing of a minigene with the missense mutations D565G, G576A and Y577F, the latter associated to classical CF. Login to comment
91 The G576A mutation resulted in a severe splicing defect, with only 7% of normal exon 12þ mRNA transcripts. Login to comment
94 These results indicate that the two missense D565G and G576A mutations associated with non-classical CF induce variable proportion of exon 12 skipping, with G576A most severely affected. Login to comment
97 To evaluate their role in CFTR exon 12 we transfected normal and the three D565G, G576A and Y577F minigenes in different cell lines (Fig. 3A). Login to comment
98 For each cell line tested, the three variants cause comparable changes in splicing efficiency, with D565G and G576A inducing exon skipping and Y577F exon inclusion. Login to comment
100 For example, G576A showed 15% of exon inclusion in NT2, 7-9% in HeLa, COS1 and T84, and complete skipping in CFPAC. Login to comment
118 In WTB, D565G and G576A, overexpression of any of the two splicing factors caused an increase in CFTR exon 12 skipping. Login to comment
119 The amount of normal transcript containing the exon 12 were reduced in WTB (40-51%), very low in D565G (7-12%) and virtually absent in the G576A mutant (Fig. 3B). Login to comment
121 These results indicate that, in the presence of high concentration of inhibitory splicing factors, the D565G and G576A missense mutations produce very low levels of normal CFTR transcripts. Login to comment
124 A total number of 26 hybrid minigenes were analysed containing site-directed mutations at two target sequences of the exon: the AAGATGC sequence at the 50 end from position 12 to 18, which includes D565G at position 15, and a central GGATAC sequence from position 47 to 52 which contains G576A and Y577F of position 48 and 51, respectively (Fig. 4). Login to comment
156 The mild CF phenotypes of the D565G and G576A patients may be explained considering that the variant CFTR protein is functional and that the defect is the consequence of exon 12 skipping induced by the nucleotide change. Login to comment
157 It is interesting to note that changes in the codon following G576A result in the classical CF mutation Y577F that produces a non-functional protein, but splicing is not significantly altered. Login to comment
162 Thus, according to tissue concentration of regulatory splicing factors, and their variations from individual to individual, the D565G and G576A may produce different quantities of mRNAs lacking the exon leading to phenotype variability. Login to comment
187 MATERIALS AND METHODS Patients and DNA mutation analysis Nasal epithelial cells were collected from six individuals carriers of mutation D565G (A>G at 1826 in CFTR cDNA), from one CBAVD patient with G576A and from four non-CF control individuals heterozygotes for the polymorphism R668C. Login to comment
189 Clinical data and CFTR genotypes of all the D565G and G576A carriers are shown in Table 2. Login to comment
225 Data on individual carriers of D565G and G576A mutations Patient code CFTR genotypea Age (years) Sex Reason for CF testing Sweat test (mEq/l) Pancreatic status 1PM D565G/À 16 F Nasal polyposis, Sa 65, 70 PS 2DF D565G 7 1717À9T>C/À 7 F Recurrent episodes of pneumonia 41.4 PS 3MA D565G/À Adult M Carrier status nt nt 4KA D565G/À Adult F Carrier status nt nt 5KP D565G/À Adult M Carrier status nt nt 6PRA D565G/À Adult F Carrier status nt nt 7ORAb D565G/À Adult M CBAVD <40 PS 8 G576A/À Adult M Testicular azoospermia nt nt PS, pancreatic sufficiency; Sa, Staphylococcus; nt, non-tested; CBAVD, congenital bilateral absence of vas deferens. Login to comment

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

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

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69 Mutations continue to be identified in association with CBAVD: A800G, G149R, R258G, E193K [Mercier et al., 1995], D1270N, and G576A [Ravnik-Glavac et al., 2000], to name a few. Login to comment

[hide] Hyperechogenic fetal bowel: a large French collabo... Am J Med Genet A. 2003 Sep 1;121A(3):209-13. Simon-Bouy B, Satre V, Ferec C, Malinge MC, Girodon E, Denamur E, Leporrier N, Lewin P, Forestier F, Muller F
Hyperechogenic fetal bowel: a large French collaborative study of 682 cases.
Am J Med Genet A. 2003 Sep 1;121A(3):209-13., 2003-09-01 [PMID:12923859]

Abstract [show]
Hyperechogenic fetal bowel is detected in 0.1-1.8% of pregnancies during the second or third trimester. This ultrasound sign is associated with cystic fibrosis or other conditions (e.g., chromosomal anomalies, viral infection) but no large-scale prospective studies have been conducted. This 1997-1998 multicenter study in 22 molecular biology laboratories identified 682 cases of hyperechogenic fetal bowel detected by routine ultrasound examination during the second (86%) or third trimester. The fetal bowel was considered hyperechogenic when its echogenicity was broadly similar to, or greater than, that of the surrounding bone. Karyotyping, screening for viral infection, and screening for cystic fibrosis mutations were performed in all cases. Pregnancy outcome and postnatal follow-up were obtained in 656 of the 682 cases (91%). In 447 cases (65.5%), a normal birth was observed. Multiple malformations were observed in 47 cases (6.9%), a significant chromosomal anomaly was noted in 24 (3.5%), cystic fibrosis in 20 (3%), and viral infection in 19 (2.8%). In utero unexplained fetal death occurred in 1.9% of cases, toxemia in 1.2%, IUGR in 4.1%, and premature birth in 6.2%. This study demonstrates that this ultrasound sign is potentially associated with medically significant outcomes. Having established that the bowel is hyperechogenic, recommended investigations should include a detailed scan with Doppler measurements, fetal karyotyping, cystic fibrosis screening, and infectious disease screening. After birth, newborns require pediatric examination because a surgical treatment may be necessary. This should be combined with clear counseling of the parents.

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55 In addition, one fetus presented with two CFTR mutations (W846X associated with the complex allele G576A-R668C) involved in congenital bilateral agenesis of the vas deferens. Login to comment

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

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

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184 The complex allele described contained three missense mutations, D443Y, G576A and R668C (Abramowicz et al. 2000). Login to comment
186 The complex allele G576A-R668C had been reported in an individual with a normal sweat test, although the affected members of the family exhibited a mild CF phenotype. Login to comment

[hide] Atypical sinusitis in adults must lead to looking ... Laryngoscope. 2004 May;114(5):839-43. Coste A, Girodon E, Louis S, Pruliere-Escabasse V, Goossens M, Peynegre R, Escudier E
Atypical sinusitis in adults must lead to looking for cystic fibrosis and primary ciliary dyskinesia.
Laryngoscope. 2004 May;114(5):839-43., [PMID:15126740]

Abstract [show]
HYPOTHESES/OBJECTIVES:: In adults, purulent pansinusitis or nasal polyposis starting early in life or that is permanently infected or associated either with chronic bronchial infection, infertility, or situs inversus are uncommon. In these atypical cases of chronic sinusitis (ACS), a primary dysfunction of the mucociliary clearance can be suspected. Adult patients with ACS were therefore investigated to detect primary ciliary dyskinesia (PCD) or cystic fibrosis (CF). STUDY DESIGN: Open, prospective study. PATIENTS AND METHODS: Forty-two patients with ACS were investigated with ciliary beat frequency and ultrastructure analysis in nasal cells and cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation analysis in blood leukocytes. RESULTS: The diagnosis of PCD was confirmed in seven (17%) patients. At least one CFTR gene mutation was detected in 16 (38%) patients. The diagnosis of CF was suggested in three (7%) compound heterozygous patients. Another 13 (31%) patients were heterozygous for a CFTR gene mutation or a complex allele. Comparison of clinical features of ACS showed that only a family history of chronic sinusitis (P <.01) or chronic bronchitis (P <.02) and the presence of diffuse bronchiectasis (P <.0001) or serous otitis media (P <.0001) were significantly more frequent in PCD patients than in patients carrying CFTR gene mutations or those without PCD or CFTR gene mutations. CONCLUSIONS: ACS should be considered a remarkable entity in which congenital abnormalities of epithelial cells are frequently detected (55% of patients). The higher frequency of mutations in ACS patients compared with the general population suggests that heterozygoty for CFTR gene mutation could be a sinusitis-causing status.

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85 Patients CFTR Gene Mutation(s) Sweat Test (mmol/L) CFTR 1 ⌬F508* 3849 ؉ 10kbC3T* 97 CFTR 2 ⌬F508* 3272-26A3G NA CFTR 3 2143delT S1235R NA CFTR 4 R74W-D1270N - NA CFTR 5 G576A-R668C - NA CFTR 6 IVS8-5T - NA CFTR 7 IVS8-5T - NA CFTR 8 R170C - 32 CFTR 9 ⌬F508* - NA CFTR 10 IVS8-5T - 44 CFTR 11 G1069R - 52 CFTR 12 IVS8-5T - 36 CFTR 13 IVS8-5T - NA CFTR 14 G551D* - NA CFTR 15 G542X* - Ͻ40 CFTR 16 F1074L - NA *Mutations detected with the CF-oligonulcleotide ligation assay kit. Login to comment

[hide] Bronchiectasis in adult patients: an expression of... Clin Genet. 2004 Jun;65(6):490-5. Casals T, De-Gracia J, Gallego M, Dorca J, Rodriguez-Sanchon B, Ramos MD, Gimenez J, Cistero-Bahima A, Olveira C, Estivill X
Bronchiectasis in adult patients: an expression of heterozygosity for CFTR gene mutations?
Clin Genet. 2004 Jun;65(6):490-5., [PMID:15151509]

Abstract [show]
While all patients with cystic fibrosis (CF) have mutations in both CFTR alleles, often only one CFTR change is detected in patients with other lung disorders. The aim of this study was to investigate whether heterozygosity for CFTR mutations could be a determinant risk factor in the development of bronchiectasis in adult patients. We have performed the CFTR gene analysis in a cohort of 55 bronchiectasis adult patients with unknown etiology. The 5T variant (TG)m and the M470V polymorphisms were also analyzed. A general population in which the same molecular analysis was previously performed was used as the control group. The mutational spectrum of patients was also compared with that found in our CF population. CFTR mutations/variants were found in 20 patients (36%), 14 with only one mutant gene (25%). All six patients colonized by Staphylococcus aureus presented with at least one CFTR change (p = 0.001). No statistical significance was observed between patients with and without mutations for other clinical features. The 5T variant was found in four patients. Additionally, 90% of patients with mutations had the more functional M470 allele (p < 0.001). These results suggest the involvement of the CFTR gene in bronchiectasis of unknown etiology in adult patients.

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73 Exceptions are the missense mutations G576A and R668C which occur on the same allele (26). Login to comment
81 Table2.ClinicalfeaturesandCFTRgenotypesfoundin20adultpatientswithbronchiectasis SampleSex/age Ageonset (years) FEV1/FVC (%predicted) Bacterial colonization Sweattest (mEq/l) Lobes affected Clinical features FirstCFTR change Second CFTRchangeM470V 1M/41520/43P30a >4-F508delL997FM/V 2F/231785/89P,S46a >4SN,ABPA,PNF508del-M/M 3F/24160/74P,S49a >4SN,PNF508del-M/V 4M/55-87/84S32a 2-F508del-M/V 5c F/372991/93S41a >4PNF508del-M/V 6F/333286/84No51a 2-G542X-M/M 7F/306101/112No56a >4-2789þ5G>A5T-12TGM/V 8F/3815106/104No29a 2OtitisS1235R-M/V 9F/34Birth75/100H20a >4SNV562L5T-11TGM/V 10d F/36530/51P20a >4SN,PNG1237S-M/V 11d M/401473/92H26a 3SN,PN,OZG1237S-M/V 12F/23541/47S23a >4HemoptysisR347HR75QV/V 13F/68548/52No34a >4PNY1014C5T-12TGV/V 14M/643088/84H39a 2-R75Q-M/V 15M/40Childhood56/79No33b >4SN,asthmaV754M-M/M 16M/474594/108No19a 2SN,PNQ179K-M/V 17M/23Childhood38/34No28a 2SN,PN5T-12TG5T-11TGM/V 18F/695068/89S52a 4DiabetesG576A,R668C-M/V 19F/47Childhood16/18P64b >4-G576A,R668C-M/V 20F/38672/88No39b >4SN,ABPA,asthma1716G/A-M/M M,male;F,female;FEV1,forcedexpiratoryvolumein1s(%ofpredictedvalueforheight);FVC,forcedvitalcapacity(%ofpredictedvalueforheight);P,Pseudomonas aeruginosa;H,Haemophilusinfluenza;S,Staphylococcusaureus;SN,sinusitis;ABPA,allergicbronchopulmonaryaspergillosis;PN,pneumonia;OZ,oligozoospermia. Login to comment
107 However, a recent study (28) has showed that the G576A change leads to exon 12 skipping and an increase of aberrant transcripts when the R668C change in exon 13 is also present. Login to comment

[hide] Characterization of cystic fibrosis conductance tr... Hum Reprod. 2004 Nov;19(11):2502-8. Epub 2004 Aug 27. Grangeia A, Niel F, Carvalho F, Fernandes S, Ardalan A, Girodon E, Silva J, Ferras L, Sousa M, Barros A
Characterization of cystic fibrosis conductance transmembrane regulator gene mutations and IVS8 poly(T) variants in Portuguese patients with congenital absence of the vas deferens.
Hum Reprod. 2004 Nov;19(11):2502-8. Epub 2004 Aug 27., [PMID:15333598]

Abstract [show]
BACKGROUND: Cystic fibrosis conductance transmembrane regulator (CFTR) gene mutations and IVS8 poly(T) variants in Portuguese patients with bilateral (CBAVD) and unilateral (CUAVD) congenital absence of the vas deferens remain to be evaluated. METHODS: Patient screening was carried out by PCR, denaturing gradient gel electrophoresis and DNA sequencing. RESULTS: CFTR mutations were found in 18 out of 31 (58.1%) CBAVD and in three of four (75%) CUAVD patients. The most frequent mutations were F508del and R334W in CBAVD and G542X in CUAVD, with the allelic frequencies of R334W (6.5%) and G542X (25%) being particular to the Portuguese population. The 5T allelic frequency was 3.5% in the fertile male population, 25% in CUAVD and 27.4% in CBAVD patients. The combined frequency of mutations (CFTR+5T) was increased in CBAVD to 22 out of 31 (71%). The frequency of CFTR mutations was compared with that of patients with secondary obstructive azoospermia (OAZ; one out of 16, 6.3%) and non-obstructive azoospermia (NOAZ; two out of 22, 9.1%) with conserved spermatogenesis, which were similar to the general population. However, whereas the 5T allelic frequency in OAZ was similar to that of the general population (3.1%), it was increased in NOAZ cases (14.3%). CONCLUSIONS: Data confirm that CFTR+5T mutations represent the most common genetic abnormality in CAVD, and suggest that cases of NOAZ may be associated with the 5T allele.

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92 The frequency of the other mutations was: four of 62 (6.5%) for R334W, two of 62 (3.2%) for R117H, P205S and G576A, and one of 62 (1.6%) for D614G, V562I, R668C, 2789-5G ! Login to comment
105 A/S1235R 1 1 - 5/7 F508del/- 6 - 6 5/9 (£6) I507del/- 1 - 1 7/9 G576A-R668C/- 1 - 1 5/7 P205S/- 1 - 1 5/5 R334W/- 1 - 1 7/7 G576A/- 1 - 1 7/7 3272-26A ! Login to comment
125 Contrary to all other countries, the second most frequent mutation found in Portugal was R334W (6.5%), whereas no differences from other countries were found regarding the third most frequent mutations, R117H, P205S and G576A (3.2%), with the exception of Germany regarding R117H (11%) (Dork et al., 1997). Login to comment

[hide] Restoration of the cystic fibrosis transmembrane c... EMBO Rep. 2004 Nov;5(11):1071-7. Nissim-Rafinia M, Aviram M, Randell SH, Shushi L, Ozeri E, Chiba-Falek O, Eidelman O, Pollard HB, Yankaskas JR, Kerem B
Restoration of the cystic fibrosis transmembrane conductance regulator function by splicing modulation.
EMBO Rep. 2004 Nov;5(11):1071-7., [PMID:15472711]

Abstract [show]
A significant fraction of disease-causing mutations affects pre-mRNA splicing. These mutations can generate both aberrant and correct transcripts, the level of which varies among different patients. An inverse correlation was found between this level and disease severity, suggesting a role for splicing regulation as a genetic modifier. Overexpression of splicing factors increased the level of correctly spliced RNA, transcribed from minigenes carrying disease-causing splicing mutations. However, whether this increase could restore the protein function was unknown. Here, we demonstrate that overexpression of Htra2-beta1 and SC35 increases the level of normal cystic fibrosis transmembrane conductance regulator (CFTR) transcripts in cystic-fibrosis-derived epithelial cells carrying the 3849+10 kb C --> T splicing mutation. This led to activation of the CFTR channel and restoration of its function. Restoration was also obtained by sodium butyrate, a histone deacetylase inhibitor, known to upregulate the expression of splicing factors. These results highlight the therapeutic potential of splicing modulation for genetic diseases caused by splicing mutations.

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13 The second group includes mutations that generate both aberrantly and correctly spliced transcripts (such as 3849 þ 10 kb C-T, 3272À26 A-G, IVS8-5T, D565G and G576A), the level of which varies among patients and among organs of the same patient (Ramalho et al, 2002; Pagani et al, 2003; reviewed in Nissim-Rafinia & Kerem, 2002). Login to comment

[hide] Rapid detection of CFTR gene rearrangements impact... J Med Genet. 2004 Nov;41(11):e118. Niel F, Martin J, Dastot-Le Moal F, Costes B, Boissier B, Delattre V, Goossens M, Girodon E
Rapid detection of CFTR gene rearrangements impacts on genetic counselling in cystic fibrosis.
J Med Genet. 2004 Nov;41(11):e118., [PMID:15520400]

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136 The subjects were divided into three groups according to the results of a previous screening: (i) 43 CF patients who fulfilled the diagnostic criteria of CF15 and who carried a CF mutation, and seven parents of deceased CF patients, a CF mutation having already been identified in the other parent (50 unidentified CF alleles); (ii) 12 CF patients with no identified CF mutation (24 unidentified CF alleles); and (iii) 16 patients apparently homozygous for a CFTR mutation and who had CF (F508del 2n = 6-, 2104insA22109del10, S945L, 3120+1GRA, N1303K) or a CFTR related disease, that is, isolated CBAVD (D110H, R117H, L997F, R74W-D1270N) or DB (R334W, R668C- G576A-D443Y) (0-16 unidentified CF alleles). 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] Molecular pathology of the CFTR locus in male infe... Reprod Biomed Online. 2005 Jan;10(1):14-41. Claustres M
Molecular pathology of the CFTR locus in male infertility.
Reprod Biomed Online. 2005 Jan;10(1):14-41., [PMID:15705292]

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

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385 (2003a) analysed the splicing pattern resulting from several variants in CFTR exon 12, including G576A (G>C at nucleotide 1859 in exon 12), which is associated in cis with R668C (C>T at nucleotide 2134 in exon 1.^). Login to comment

[hide] Pharmacological induction of CFTR function in pati... Pediatr Pulmonol. 2005 Sep;40(3):183-96. Kerem E
Pharmacological induction of CFTR function in patients with cystic fibrosis: mutation-specific therapy.
Pediatr Pulmonol. 2005 Sep;40(3):183-96., [PMID:15880796]

Abstract [show]
CFTR mutations cause defects of CFTR protein production and function by different molecular mechanisms. Mutations can be classified according to the mechanisms by which they disrupt CFTR function. This understanding of the different molecular mechanisms of CFTR dysfunction provides the scientific basis for the development of targeted drugs for mutation-specific therapy of cystic fibrosis (CF). Class I mutations are nonsense mutations that result in the presence of a premature stop codon that leads to the production of unstable mRNA, or the release from the ribosome of a short, truncated protein that is not functional. Aminoglycoside antibiotics can suppress premature termination codons by disrupting translational fidelity and allowing the incorporation of an amino acid, thus permitting translation to continue to the normal termination of the transcript. Class II mutations cause impairment of CFTR processing and folding in the Golgi. As a result, the mutant CFTR is retained in the endoplasmic reticulum (ER) and eventually targeted for degradation by the quality control mechanisms. Chemical and molecular chaperones such as sodium-4-phenylbutyrate can stabilize protein structure, and allow it to escape from degradation in the ER and be transported to the cell membrane. Class III mutations disrupt the function of the regulatory domain. CFTR is resistant to phosphorylation or adenosine tri-phosphate (ATP) binding. CFTR activators such as alkylxanthines (CPX) and the flavonoid genistein can overcome affected ATP binding through direct binding to a nucleotide binding fold. In patients carrying class IV mutations, phosphorylation of CFTR results in reduced chloride transport. Increases in the overall cell surface content of these mutants might overcome the relative reduction in conductance. Alternatively, restoring native chloride pore characteristics pharmacologically might be effective. Activators of CFTR at the plasma membrane may function by promoting CFTR phosphorylation, by blocking CFTR dephosphorylation, by interacting directly with CFTR, and/or by modulation of CFTR protein-protein interactions. Class V mutations affect the splicing machinery and generate both aberrantly and correctly spliced transcripts, the levels of which vary among different patients and among different organs of the same patient. Splicing factors that promote exon inclusion or factors that promote exon skipping can promote increases of correctly spliced transcripts, depending on the molecular defect. Inconsistent results were reported regarding the required level of corrected or mutated CFTR that had to be reached in order to achieve normal function.

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59 T, 1811 þ 1.6 kb A >G, 3272 À 26A !G, IVS8-5T, D565G, G576A, c4006 À 1 G À> A, 2789 þ 5 G > A 1 Included are mutations that have been studied in RNA/protein level or having enough experimental data to suggest their molecular mechanism. Login to comment
234 CLASS V MUTATIONS: REDUCED NUMBER OF ACTIVE CFTR This group includes mutations which generate both aberrantly and correctly spliced transcripts (such as 3849 þ 10 kb C -> T, 3272 À 26 A -> G, IVS8-5T, D565G, and G576A), the levels of which vary among different patients and among different organs of the same patient.85-89 These patients often have a relatively mild phenotype, yet with variable disease expression, from minimal lung disease, pancreatic sufficiency, and male fertility to relatively severe disease with multiorgan involvement.88,89 This variable disease expression is inversely correlated with the level of correctly spliced transcripts, such that lower levels are associated with a severe disease, while higher levels are associated with a milder phenotype. Login to comment

[hide] Complete cystic fibrosis transmembrane conductance... Gut. 2005 Oct;54(10):1456-60. Epub 2005 Jun 29. Weiss FU, Simon P, Bogdanova N, Mayerle J, Dworniczak B, Horst J, Lerch MM
Complete cystic fibrosis transmembrane conductance regulator gene sequencing in patients with idiopathic chronic pancreatitis and controls.
Gut. 2005 Oct;54(10):1456-60. Epub 2005 Jun 29., [PMID:15987793]

Abstract [show]
BACKGROUND: Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene-many of which cause cystic fibrosis-have also been reported in patients with chronic pancreatitis. The authors examine whether mild or severe CFTR mutations, homozygous or compound heterozygous CFTR mutations, or even simple cystic fibrosis carrier status alone increases the risk of developing pancreatitis. METHODS: After exclusion of patients with trypsinogen (PRSS1) mutations, cystic fibrosis, or pulmonary disease, and with known risk factors for pancreatitis 67 patients with idiopathic chronic pancreatitis (ICP) from northwest Germany and 60 geographically and ethnically matched controls were recruited. The entire coding region of the CFTR gene was sequenced in all patients and controls. ICP patients were also analysed for serine protease inhibitor Kazal type 1 (SPINK1) gene mutations. RESULTS: Abnormal CFTR alleles were found to be twice as frequent in ICP patients as in controls (25/134 v 11/120; p<0.05). Three of four severe CFTR mutations detected in patients were compound heterozygous with another abnormal CFTR allele, whereas among controls three severe CFTR mutations were found in heterozygous cystic fibrosis carriers. In ICP patients 19 uncommon/mild mutations, including combinations of the 5T allele with 12TG repeats, were identified compared with only five in controls (p = 0.012). Heterozygous SPINK1 mutations were detected in eight ICP patients (15% v 1% in controls) but only one also carried an additional mild CFTR mutation. CONCLUSIONS: These data show that not only compound heterozygosity, but also cystic fibrosis carrier status for different types of CFTR mutations, including uncommon/mild mutations, significantly increase the risk of developing pancreatitis. Although 45% of the study's ICP patients carried predisposing genetic risk factors (for example, mutations in CFTR or SPINK1), the authors found no evidence that the risk conveyed by CFTR mutations depends on co-inherited SPINK1 mutations.

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237 In the group of ICP patients being heterozygous for a single CFTR mutation one severe (2184insA, this insertion causes a frame shift) and eight mild/uncommon mutations (26 S1235R, R31C, R75Q, R347P, G576A, M348V, and V754M) were identified. Login to comment
256 The reason why numbers for compound heterozygous ICP patients in these studies are diverse (4/67 = 6% in our study) may be due to differences Table 1 CFTR and SPINK1 sequence variations identified in 30 of the 67 ICP patients PatientSex CFTR mutation T allele TG repeats PSTI mutation 1 M DF508/R117H 7/7 9/10 -/- 2 W DF508/A1087P 7/9 10/11 -/- 3 M DF508/D1152H 7/9 10/10 -/- 4 M S1235R/R668C 7/7 11/12 -/- 5 M 2184insA/- 7/7 10/12 -/- 6 M R31C/- 7/7 10/11 -/- 7 M R75Q/- 7/7 11/11 -/- 8 M R347P/- 7/7 11/12 -/- 9 M S1235R/- 7/7 11/12 -/- 10 W S1235R/- 7/7 11/12 -/- 11 M G576A/- 7/7 10/10 -/- 12 W M348V/- 7/9 10/10 -/- 13 M V754M/- 7/7 10/11 -/- 14 M -/- 5/7 11/12 -/- 15 W -/- 5/7 11/12 -/- 16 M -/- 5/7 11/12 -/- 17 W -/- 5/9 11/12 -/- 18 M -/- 5/7 11/12 -/- 19 M -/- 5/7 10/10 -/- 20 W -/- 5/7 10/10 -/- 21 W -/- 5/7 11/12 N34S/- 22 W -/- 7/7 10/11 N34S/- 23 M -/- 7/9 10/11 N34S/- 24 M -/- 7/7 11/11 N34S/- 25 M -/- 7/7 11/11 N34S/- 26 W -/- 7/7 11/11 N34S/- 27 M -/- 7/7 11/11 N34S/- 28 W -/- 7/7 10/11 N34S/- 29 W -/- 7/7 11/11 P55S/- 30 W -/- 7/7 11/11 IVS3+2TC/- Table 2 CFTR sequence variations identified in 11 of 60 healthy controls Control group Number DF508/- 3 R117H/- 2 I148T/- 1 L997F/- 1 5T/12TG 1 5T/11TG 3 in patient recruitment, the catchment populations, or the stringency with which cystic fibrosis patients were excluded. Login to comment

[hide] Genetics of idiopathic disseminated bronchiectasis... Semin Respir Crit Care Med. 2003 Apr;24(2):179-84. Luisetti M, Pignatti PF
Genetics of idiopathic disseminated bronchiectasis.
Semin Respir Crit Care Med. 2003 Apr;24(2):179-84., [PMID:16088537]

Abstract [show]
Bronchiectasis is an abnormal dilation of bronchi, consequent to the destruction of their walls. It is included in the category of obstructive pulmonary diseases, along with chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis. In approximately 50% of cases, bronchiectasis is associated with underlying conditions; in the remainder, known causes are not ascertainable (idiopathic bronchiectasis). A search for genetic determinants of this phenotype, with the cystic fibrosis gene as a candidate, has been performed by three independent groups. The results of this search agreed on the association of bronchiectasis with cystic fibrosis gene mutations and polymorphisms. The cystic fibrosis gene is also associated with bronchiectasis due to rheumatoid arthritis and allergic bronchopulmonary aspergillosis. A few other genes have been investigated in idiopathic bronchiectasis, with negative results. Idiopathic bronchiectasis is, therefore, to be considered as an obstructive multifactorial disorder belonging to the category of cystic fibrosis monosymptomatic diseases (or CFTR-opathies), whose pathogenesis is influenced by environmental factors and other undetermined genes.

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42 Greek M/F 11/12 5/16 na Mean age (yrs) 53 Ϯ 15 53 Ϯ 14 na CFTR gene 1 G576A-R668C/L997F 1 ⌬F508/D192N 1 ⌬F508,I1027T mutation 1 ⌬F508/L997F 1 ⌬I507/3849 + 10kb C → T 1 D565G, R668C 1 ⌬F508/- 1 ⌬F508/3849 + 10kb C → T 1 T896I/- 1 R1066C/- 1 H949Y/T1220I 1 I148T/- 1 3667ins4/- 1 ⌬F508/- 1 ⌬F508/S977F 1 R75Q/- 1 2183AA→G 1 M1137V/- 1 L997F/- IVS8-5T 5 5/7 1 5/9 1 5/5 CFTR, cystic fibrosis transmembrane conductance regulator; na, not available. Login to comment
46 The mutations found are listed by the CF Genetic Analysis Consortium as CF mutations (CFGAC),14 with the exception of G576A and R668C, which are not likely to cause CF14 and have been found in patients affected by congenital bilateral absence of the vas deferens (CBAVD). Login to comment

[hide] Extensive sequencing of the CFTR gene: lessons lea... Hum Genet. 2005 Dec;118(3-4):331-8. Epub 2005 Sep 28. McGinniss MJ, Chen C, Redman JB, Buller A, Quan F, Peng M, Giusti R, Hantash FM, Huang D, Sun W, Strom CM
Extensive sequencing of the CFTR gene: lessons learned from the first 157 patient samples.
Hum Genet. 2005 Dec;118(3-4):331-8. Epub 2005 Sep 28., [PMID:16189704]

Abstract [show]
Cystic fibrosis (CF) is one of the most common monogenic diseases affecting Caucasians and has an incidence of approximately 1:3,300 births. Currently recommended screening panels for mutations in the responsible gene (CF transmembrane regulator gene, CFTR) do not detect all disease-associated mutations. Our laboratory offers extensive sequencing of the CFTR (ABCC7) gene (including the promoter, all exons and splice junction sites, and regions of selected introns) as a clinical test to detect mutations which are not found with conventional screening. The objective of this report is to summarize the findings of extensive CFTR sequencing from our first 157 consecutive patient samples. In most patients with classic CF symptoms (18/24, 75%), extensive CFTR sequencing confirmed the diagnosis by finding two disease-associated mutations. In contrast, only 5 of 75 (7%) patients with atypical CF had been identified with two CFTR mutations. A diagnosis of CF was confirmed in 10 of 17 (58%) newborns with either positive sweat chloride readings or positive immunoreactive trypsinogen (IRT) screen results. We ascertained ten novel sequence variants that are potentially disease-associated: two deletions (c.1641AG>T, c.2949_2853delTACTC), seven missense mutations (p.S158T, p.G451V, p.K481E, p.C491S, p.H949L, p.T1036N, p.F1099L), and one complex allele ([p.356_A357del; p.358I]). We ascertained three other apparently novel complex alleles. Finally, several patients were found to carry partial CFTR gene deletions. In summary, extensive CFTR gene sequencing can detect rare mutations which are not found with other screening and diagnostic tests, and can thus establish a definitive diagnosis in symptomatic patients with previously negative results. This enables carrier detection and prenatal diagnosis in additional family members.

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76 Meconium peritonitis;pseudocyst; volvulus 6 p.W1282X/p.S492F 2 months M IRT positive 57, 78, 75, 80, 81 Dx of CF, symptomatic 7 DF508/p.F1099Lb 2 months M IRT positive 48, 52 Asymptomatic at this point 8 DF508/[p.R352W; pP750L]c 1.5 months M IRT positive 1 nl, 44 Followed in CF clinic, being treated prophylactically, neg. elastase 9 DF508/c.1154insTC 4 days M Meconium ileus at birth Not done CF, two affected sibs 10 DF508/c.2789+2insA 2 months F IRT positive 58,57,53 Dx of CF a Concentrations >60 mmol/l on repeated analysis are diagnostic for cystic fibrosis b Novel CFTR mutation c Complex CFTR allele with two different mutations Table 4 Complex CFTR alleles observed in a series of 157 patient samples after extensive sequencing Subject Genotype Phenotype Age Sweat chloride concentration (mmol/l) 1 [p.G576A;p.R668C]/wta Chronic cough, sinusitis, and recurrent pneumonia 3 years Normal 2 p.R1158X/[p.V562I;p.A1006E] Mild CF 40 years 115 3 DF508/[p.R352W;p.P750L] Abnormal newborn screen 49 days 44 4 [c.1198_1203delTGGGCT;c.1204G>A]/wt Mild CF (respiratory symptoms) 12 years 110, 115 a This complex allele has been previously described in a patient with disseminated bronchiectasis with L997F on the other allele (Pignatti et al. 1995) Table6NovelCFTRvariantsfoundinaseriesof157patientsamplesafterextensivesequencing SubjectMutation type LocationNucleotidechangeEffectonproteinCFTRdomaina Mutationonother allele Phenotype 1MissenseExon4c.605G>Cp.S158TL1Nonedetected4-month-oldmale,abnormalnewbornscreen; 3borderlinesweattestresults 2ComplexalleleExon7[c.1198_1203delTGGGCT; c.1204G>A] [p.W356_A357del; p.V358I] AfterTM6and beforeNBD1 Nonedetected12-year-oldmale,meconiumilleusatbirth, respiratorysymptomsofCF;positivesweatchlorides (110,115mmol/l).Motheralsocarriescomplexallele 3MissenseExon9c.1484G>Tp.G451VNBD1DF50819-year-oldmale,diagnosisofCF 4MissenseExon10c.1573A>Gp.K481ENBD1Nonedetected15-year-oldmale,atypicalCF,asthma,2borderline sweatchlorides(low60s) 5MissenseExon10c.1604G>Cp.C491SNBD1NonedetectedNoabnormalsymptoms;sisterofCFpatientthat carriesp.P67L/DF508.Probablebenign variantascertainedduring singleexonsequencingofexon10 6DeletionExon10c.1641AG>Tp.K503NfsX23NBD1p.H609R22-year-oldmale,classicCF,PI,positivesweat chloride(>100mmol/l) 7DeletionExon15c.2949_2953delTACTCp.H939fsX32L3DF5083-month-oldfemale,diagnosisofCF,positivesweat chloride(105mmol/l) 8MissenseExon15c.2978A>Tp.H949LL3Nonedetected, but5Tpositive 12-year-oldmale,atypicalCF,sinusproblems. Login to comment
57 Subject 1 had a complex allele ([p.G576A; p.R668C]) which had been previously described in a patient with disseminated bronchiectasis (Pignatti et al. 1995). 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] A new large CFTR rearrangement illustrates the imp... Hum Mutat. 2006 Jul;27(7):716-7. Niel F, Legendre M, Bienvenu T, Bieth E, Lalau G, Sermet I, Bondeux D, Boukari R, Derelle J, Levy P, Ruszniewski P, Martin J, Costa C, Goossens M, Girodon E
A new large CFTR rearrangement illustrates the importance of searching for complex alleles.
Hum Mutat. 2006 Jul;27(7):716-7., [PMID:16786510]

Abstract [show]
The p.Val754Met variant, described in 1996 in a CF patient, has been considered a CF mutation. However, biochemical aspects, results of functional studies and, finally, the identification of a complex deletion removing exons 3 to 10 and 14b to 16 in cis of p.Val754Met in a CF patient, argue against a strong deleterious effect. An inventory through the French CF network of patients carrying p.Val754Met led to the registration of seven patients (CF: n=4; idiopathic chronic pancreatitis: n=3) and six healthy individuals, all heterozygous for the variation. Extensive CFTR gene analysis was carried out, including the search for large rearrangements and other possible mutations. The complex deletion, whose breakpoints are described here, was found only in the four CF patients, in association with the same haplotype. This data, added to the fact that the p.[Phe508del]+[Val754Met] genotype was found in a healthy individual, bring further arguments against the association of p.Val754Met with CF. We thus suggest looking for a possible complex allele whenever p.Val754Met is detected and considering it neutral regarding genetic counseling when found in isolation.

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101 [Gly576Ala; Arg668Cys] (Grangeia et al., personal communication). Login to comment

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

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

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54 Patients With More Than 1 CFTR Mutation CFTR Mutation 1 CFTR Mutation 2 CFTR Mutation 3 No. of Patients deltaF508 5T 3 deltaF508 D1152H 1 deltaF508 deltaF508 1 deltaF508 F575Y 1 deltaF508 K598E 1 deltaF508 T164S 1 deltaF508 R74W D1270N 1 deltaF508 Q1476X 1 deltaF508 L997F 1 R553X D1152H 1 R553X G1069R 1 2789+5 G9A 2183 AA9G 1 3849+10kb C9T L1260P 1 711+3 A to G I1139V 1 1341+1 G9A G194R 5T 1 621+25 A9G 3500-19 C9T 1 R74W V855I 1 G542X R117H 1 G551D F311L 1 G576A R668C 2 K710X L997F 1 L997F L320V 1 G1069R 5T 1 1818+18 G9A 5T 1 F1074L 5T 1 F834L 5T 1 R74Q R297Q 1 R74Q R297Q 5T 1 R785Q 5T 1 R117H 5T 3 deltaF508 I1027T 1 Total patients 36 MutationsinboldfacewouldnothavebeendetectedbytheAmericanCollegeofObstetrics and Gynecology (ACOG)/American College of Medical Genetics (ACMG) mutation panel. Login to comment

[hide] Detection of cystic fibrosis transmembrane conduct... Hum Reprod. 2007 May;22(5):1285-91. Epub 2007 Feb 28. Ratbi I, Legendre M, Niel F, Martin J, Soufir JC, Izard V, Costes B, Costa C, Goossens M, Girodon E
Detection of cystic fibrosis transmembrane conductance regulator (CFTR) gene rearrangements enriches the mutation spectrum in congenital bilateral absence of the vas deferens and impacts on genetic counselling.
Hum Reprod. 2007 May;22(5):1285-91. Epub 2007 Feb 28., [PMID:17329263]

Abstract [show]
BACKGROUND: Mutations in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene have been widely detected in infertile men with congenital bilateral absence of the vas deferens (CBAVD). Despite extensive analysis of the CFTR gene using varied screening methods, a number of cases remain unsolved and could be attributable to the presence of large gene rearrangements, as recently shown for CF patients. METHODS: We carried out a complete CFTR gene study in a group of 222 CBAVD patients with strict diagnosis criteria and without renal anomaly, and searched for rearrangements using a semi-quantitative assay in a subgroup of 61 patients. RESULTS: The overall mutation detection rate was 87.8%, and 82% of patients carried two mutations. Ten out of the 99 different mutations accounted for 74.6% of identified alleles. Four large rearrangements were found in patients who already carried a mild mutation: two known partial deletions (exons 17a to 18 and 22 to 23), a complete deletion and a new partial duplication (exons 11 to 13). The rearrangements accounted for 7% of the previously unknown alleles and 1% of all identified alleles. CONCLUSIONS: Screening for rearrangements should be part of comprehensive CFTR gene studies in CBAVD patients and may have impacts on genetic counselling for the patients and their families.

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69 Frequent cystic fibrosis transmembrane conductance regulator (CFTR) defects found in congenital bilateral absence of the vas deferens (CBAVD) patients (above 1% among the identified alleles) Mutation No. of alleles % of the 390 identified alleles F508dela 119 30.5 IVS8(T)5a,b 107 27.4 (TG)12(T)5 82 (TG)13(T)5 16 (TG)11(T)5b 9 R117Ha 25 6.4 R668C 9 2.3 [D443Y;G576A;R668C] 6 [G576A;R668C] 2 R668C 1 L206W 7 1.8 D1152H 6 1.5 W1282Xa 5 1.3 [V562I;(TG)11(T)5] 5 1.3 [R74W;D1270 N] 4 1.0 [R74W;D1270 N] 3 [R74W;V201M;D1270 N] 1 Q1352H(G . Login to comment
84 1 [G576A;R668C] þ [?] Login to comment

[hide] Molecular characterization of the cystic fibrosis ... Genet Med. 2007 Mar;9(3):163-72. Grangeia A, Sa R, Carvalho F, Martin J, Girodon E, Silva J, Ferraz L, Barros A, Sousa M
Molecular characterization of the cystic fibrosis transmembrane conductance regulator gene in congenital absence of the vas deferens.
Genet Med. 2007 Mar;9(3):163-72., [PMID:17413420]

Abstract [show]
PURPOSE: Approximately 20% of patients with congenital absence of the vas deferens remain without two mutations identified. We applied a strategy of serial screening steps to 45 patients with congenital absence of the vas deferens and characterized cystic fibrosis transmembrane conductance regulator gene mutations in all cases. METHODS: DNA samples of 45 patients with congenital absence of the vas deferens were screened by successive different molecular genetics approaches. RESULTS: Initial screening for the 31 most frequent cystic fibrosis mutations, IVS8 poly(TG)m, poly(T)n, and M470V polymorphisms, identified 8 different mutations in 40 patients (88.9%). Extensive cystic fibrosis transmembrane conductance regulator gene analysis by denaturing gradient gel electrophoresis, denaturing high-performance liquid chromatography, and DNA sequencing detected 17 further mutations, of which three were novel. Cystic fibrosis transmembrane conductance regulator gene rearrangements were searched by semiquantitative fluorescent multiplex polymerase chain reaction, which detected a CFTRdele2,3 (21 kb) large deletion and confirmed two homozygous mutations. Overall, 42 patients (93.3%) had two mutations and 3 patients (6.7%) had one mutation detected. CONCLUSIONS: The present screening strategy allowed a higher mutation detection rate than previous studies, with at least one cystic fibrosis transmembrane conductance regulator gene mutation found in all patients with congenital absence of the vas deferens.

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85 Three mutations were found as complex alleles (two or three sequence alterations associated in cis on the same allele), each in two patients, G576A-R668C, D443Y-G576A-R668C, and S1235R-T5 (one patient with T5 in homozygosity) (Table 2). Login to comment
94 a Missense mutations linked on the same allele, G576A-R688C and D443Y-G576A-R688C, were present in two patients with CBAVD each. CFTR mutations: severe (bold); novel (italics). Login to comment
97 The allelic frequency of the other mutations was 4.4% for R117H, G576A, and R668C, 3.3% for S1235R and 3272-26A¡G, and 2.2% for P205S, L206W, D443Y, G542X, D614G, and N1301K, whereas the remaining 12 mutations were present in single patients (Table 3). Login to comment
101 The missense M470V polymorphism was evaluated in all 45 pa- tientswithCAVD(Table2).TheallelicfrequencyoftheM470variant Table 2 CFTR genotypes identified in patients with congenital absence of the vas deferens CFTR mutation genotypes [(TG)mTn] genotype M470V Patients N % DeltaF508 (TG)10T9 (TG)12T5 M V 11 24.4 DeltaF508 (TG)10T9 (TG)11T5 M M 1 2.2 DeltaF508 R117H (TG)10T9 (TG)10T7 M M 2 4.4 G542X (TG)10T9 (TG)12T5 M V 2a 4.4 DeltaF508 R334W (TG)10T9 (TG)11T7 M V 1 2.2 DeltaF508 D443Y-G576A-R668C (TG)10T9 (TG)10T7 M M 1 2.2 DeltaF508 D614G (TG)10T9 (TG)11T7 M V 1 2.2 DeltaF508 E831X (TG)10T9 (TG)11T7 M V 1 2.2 DeltaF508 L1227S (TG)10T9 (TG)11T7 M M 1 2.2 DeltaF508 E1401K (TG)10T9 (TG)11T7 M V 1 2.2 I507del D614G (TG)11T7 (TG)10T7 M V 1 2.2 N1303K L206W (TG)10T9 (TG)9T9 M M 1 2.2 R117H P205S (TG)11T7 (TG)10T7 M V 1 2.2 R117H R334W (TG)10T7 (TG)11T7 M V 1 2.2 R334W P439S (TG)11T7 (TG)11T7 M V 1 2.2 R334W R334Wb (TG)11T7 (TG)11T7 V V 1 2.2 R334W V562I (TG)11T7 (TG)11T5 V M 1 2.2 D443Y-G576A-R668C 3272-26A¡G (TG)10T7 (TG)10T7 M M 1 2.2 G576A-R668C V754Mb (TG)10T7 (TG)11T7 M M 1 2.2 S1235R S1235Rb (TG)13T5 (TG)13T5 M M 1 2.2 2789ϩ5G¡A S1235Rb (TG)10T7 (TG)13T5 M M 1 2.2 3272-26A¡G P1290S (TG)11T7 (TG)10T7 M V 1 2.2 P205S (TG)11T7 (TG)12T5 V V 1 2.2 G576A-R668C b (TG)10T7 (TG)11T5 M M 1 2.2 V1108L b (TG)11T7 (TG)11T5 V M 1 2.2 N1303K (TG)10T9 (TG)12T5 M V 1 2.2 3272-26A¡G b (TG)10T7 (TG)12T5 M V 1 2.2 CFTRdele2,3 b (TG)11T7 (TG)13T5 V M 1 2.2 b (TG)11T5 (TG)12T5 M V 1 2.2 b (TG)13T5 (TG)12T5 M V 1 2.2 DeltaF508 - (TG)10T9 (TG)11T7 M V 1a 2.2 L206W -b (TG)9T9 (TG)11T7 M V 1 2.2 R258G -b (TG)11T7 (TG)11T7 V V 1 2.2 a CUAVD. Login to comment
110 Large Table 3 Allelic frequencies of CFTR mutations in patients with congenital absence of the vas deferens CBAVD CUAVD Total Patients 42 3 45 Alleles 84 6 90 Mutations N % N % N % 1 T5 allele 26a 31 2 33.3 28 31.1 2 DeltaF508 20 23.8 1 16.7 21 23.3 3 R334W 6a 7.1 0 0 6 6.7 4 R117H 4 4.8 0 0 4 4.4 5 G576A 4b 4.8 0 0 4 4.4 6 R688C 4b 4.8 0 0 4 4.4 7 S1235R 3a 3.6 0 0 3 3.3 8 3272-26A¡G 3 3.6 0 0 3 3.3 9 P205S 2 2.4 0 0 2 2.2 10 L206W 2 2.4 0 0 2 2.2 11 D443Y 2b 2.4 0 0 2 2.2 13 D614G 2 2.4 0 0 2 2.2 14 N1303K 2 2.4 0 0 2 2.2 12 G542X 0 0 2 33.3 2 2.2 15 R258G 1 1.2 0 0 1 1.1 16 P439S 1 1.2 0 0 1 1.1 17 I507del 1 1.2 0 0 1 1.1 18 V562I 1 1.2 0 0 1 1.1 19 V754M 1 1.2 0 0 1 1.1 20 E831X 1 1.2 0 0 1 1.1 21 2789ϩ5G¡A 1 1.2 0 0 1 1.1 22 V1108L 1 1.2 0 0 1 1.1 23 L1227S 1 1.2 0 0 1 1.1 24 P1290S 1 1.2 0 0 1 1.1 25 E1401K 1 1.2 0 0 1 1.1 26 CFTRdele2,3 1 1.2 0 0 1 1.1 CBAVD, congenital bilateral absence of the vas deferens; CUAVD, congenital unilateral absence of the vas deferens. Login to comment
112 b Missense mutations linked on the same allele, G576A-R688C and D443Y-G576A-R688C, were present in two patients with CBAVD each. CFTR gene rearrangements are not detectable using conventional PCR-based screening techniques, because the amplification of a nondeleted allele masks the lack of a PCR product corresponding to the deletion site.21,22,24 This detected a CFTRdele2,3 (21 kb) deletion in a Ukrainian emigrant with CBAVD and heterozygous for the T5 allele. Login to comment
142 In fact, they occur in highly conserved regions of the CFTR protein, which share 100% amino acid sequence homology between species48 and affect the NBD1, NBD2, and transmembrane regions of the protein, which are known to regulate chloride conductance and permeability.49-51 P439S was previously reported in a child with CF with pancreatic insufficiency and mild lung disease, in association with the P439S/R688C genotype.52 The E1401K mutation occurs at a position in which other mutations, E1401X and E1401A, have been described in patients with CF with pancreatic insufficiency.8 Some difficulties in defining CF or CAVD-causing mutations were observed with some missense mutations.6,27 G576A and R668C have been found independently, in pairs, or combined with the D443Y mutation on the same chromosome in patients withaCF-relatedsyndrome.Inaccordancewithpreviousstudies, we expected that G576A and R668C were located in cis in two patients and combined with D443Y in the same chromosome in two patients.6,9,12 Although initially described as polymorphisms,27 they were later considered mild mutations associated with the CBAVD phenotype when combined in trans with the severedeltaF508mutation.53 However,ourpresentresultssuggest they might also cause the CAVD phenotype when associated with other mild CFTR mutations, because three of four patients carry- ingthesecomplexallelesharboredamildorverymildmutationin the other chromosome (D443Y-G576A-R668C/3272-26A¡G, Table 5 Comparative analysis of CFTR mutation allelic frequencies (%) in patients with congenital absence of the vas deferens Countries Patients T5 allele DeltaF508 R334W R117H References Argentina 36 NA 20.8 NA 5.6 43 Austria 22 NA 13.6 NA 9.1 44 Italy 12 8.3 29.2 NA 4.2 39 The Netherlands 21 9.5 19.0 NA 21.4 38 Germany 106 12.3 26.4 0.5 11.3 30 Greece 14 14.3 14.3 NA NA 32 France 800 16.3 21.8 NA 4.4 6 United States 92 17.9 21.2 NA 2.2 41 Canada 74 18.2 16.9 1.4 6.1 5 Turkey 51 19.6 2.9 NA NA 35 Brazil 17 20.6 11.7 NA 2.9 34 Spain 134 20.9 16.0 0.4 3.0 33 Iran 113 25.7 12.4 0.9 3.5 37 Egypt 16 43.7 6.2 NA NA 40 Taiwan 27 44.4 NA NA NA 42 Portugal 45 31.1 23.3 6.7 4.4 13, 36, PS NA, not available; PS, present study. Login to comment
143 G576A-R668C/V754M, G576A-R668C/T5), and only one case was associated with a severe mutation (DeltaF508del/D443Y-G576A-R668C). Login to comment

[hide] Contribution of the CFTR gene, the pancreatic secr... Clin Genet. 2007 May;71(5):451-7. Tzetis M, Kaliakatsos M, Fotoulaki M, Papatheodorou A, Doudounakis S, Tsezou A, Makrythanasis P, Kanavakis E, Nousia-Arvanitakis S
Contribution of the CFTR gene, the pancreatic secretory trypsin inhibitor gene (SPINK1) and the cationic trypsinogen gene (PRSS1) to the etiology of recurrent pancreatitis.
Clin Genet. 2007 May;71(5):451-7., [PMID:17489851]

Abstract [show]
Acute recurrent/chronic pancreatitis (CP) is a complex multigenic disease. This is a case-control study consisting of 25 Greek patients with CP and a control population of 236 healthy Greek subjects. The whole coding area and neighboring intronic regions of the three genes were screened. Seventeen of 25 patients (68%) had mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene: nine compound heterozygotes with either mild or severe mutations and eight heterozygotes. Four patients (16%) carried CFTR-modulating haplotypes V470-TG11-T5 and V470-TG12-T7. All were negative for PRSS1 gene mutations, while variants c.486C/T and c.738C/T were found in nine patients each, three homozygotes for the minor alleles. Two carried SPINK1 gene mutation p.N34S, one being transheterozygote with CFTR mutation p.F1052V. The promoter variant -253T>C was found in four individuals (one homozygous for the minor allele), all four being transheterozygotes with mutations in the CFTR gene as well. Finally two carried c.272C/T in the 3' untranslated region, one being a p.N34S carrier as well. In total, 80% (20/25) of patients had a molecular defect in one or both of the CFTR and SPINK1 genes, suggesting that mutations/variants in the CFTR plus or minus mutations in the SPINK1, but not the PRSS1 gene, may confer a high risk for recurrent pancreatitis.

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62 Molecular findings for the CFTR gene Eight patients were carriers (16%): three with p.R1070Q and five with p.F508del, p.G576A, p.F1052V, CFTRdel2,3 (21 kb), and c.2752215G/C, each, representing a heterozygote frequency 2.1-fold higher than that found in the 211 general population controls (7.6%, p , 0.0001). Login to comment
87 Mutation p.G576A, found in transheterozygote state with SPINK1 2253T/C promoter variant in our patient, has previously been reported in a CP patient, although the previous study did not screen the SPINK1 gene as well (16). Login to comment
90 Mutations and variants in the CFTR gene CFTR mutation/variant Patients with pancreatitis, n ¼ 25 (%) Controlsa , n ¼ 211 (%) Classic patients with CF, n ¼ 426 (%) p vs controls p vs patients with CF p.F508del 5 (10) 2 (0.47) 465 (54.6) ,0.0001 ,0.0001 p.R334W 4 (8) - 7 (8.2) 0.00011 0.0019 c.444delA 1 (2) - 1 (0.1) c.278915G.A 2 (4) - 11 (1.3) 0.011 CFTRdel2,3 (21 kb) 1 (2) - 2 (0.2) c.E822X 2 (4) - 12 (1.5) 0.011 p.R347H 1 (2) - - 0.055 p.R1070Q 3 (6) 1 (0.24) 7 (0.8) 0.004 0.013 p.G576A 1 (2) - 1 (0.1) p.F1052V 1 (2) 4 (0.95) 1 (0.1) p.I148T 1 (2) - 1 (0.1) c.3272226A.G 1 (2) - 7 (0.82) p.R75Q 2 (4) 4 (0.95) 1 (0.1) 0.0086 c.2752215G/C 1 (2) 4 (1) 5 (0.6) TG11T7 26 (52) 286 (67.7) ND TG11T5 2 (4) 5 (1.18) ND TG10T7 8 (16) 79 (18.7) ND TG10T9 8 (16) 14 (3.3) ND 0.0005 TG12T7 2 (4) 8 (1.9) ND M470 6 (12) 48 (11.4) ND V470 8 (16) 166 (39.3) ND 0.008 CF, cystic fibrosis; ND, not determined. Login to comment
99 Promoter variant 2253T/C was detected in three patients all trans-heterozygotes with CFTR: two with p.R1070Q, and one with p.G576A. Login to comment

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

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

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98 Allele fraction (%) 1 125GϾC 3.8 3 356GϾA R75Q 3.5 4 605GϾC S158T Ͻ0.4b,c 6b 1001 ϩ 11CϾT 13.1 10 1540AϾG M470V 30.0d 1716GϾA 1.5 12 1859GϾC G576A 1.5 13 2134CϾT R668C 1.5 14a 2694TϾG 26.2 14b 2752 - 6TϾC 0.4 15 3032TϾC L967S 0.8 17b 3417AϾT T109S 1.5 19 3601 - 17TϾC 0.4 20 3891GϾA Ͻ0.4b,c 4002AϾG 1.5 21 4029AϾG 0.4 23 4294CϾG L1388V 0.4b 4316GϾA C1395Y 0.4b 4374 ϩ 13AϾG 0.4 24 4404CϾT 0.8 4521GϾA 20.8 a All variants were identified by scanning random panels and confirmed by sequencing. Login to comment

[hide] N-terminal CFTR missense variants severely affect ... Hum Mutat. 2008 May;29(5):738-49. Gene GG, Llobet A, Larriba S, de Semir D, Martinez I, Escalada A, Solsona C, Casals T, Aran JM
N-terminal CFTR missense variants severely affect the behavior of the CFTR chloride channel.
Hum Mutat. 2008 May;29(5):738-49., [PMID:18306312]

Abstract [show]
Over 1,500 cystic fibrosis transmembrane conductance regulator (CFTR) gene sequence variations have been identified in patients with cystic fibrosis (CF) and related disorders involving an impaired function of the CFTR chloride channel. However, detailed structure-function analyses have only been established for a few of them. This study aimed evaluating the impact of eight N-terminus CFTR natural missense changes on channel behavior. By site-directed mutagenesis, we generated four CFTR variants in the N-terminal cytoplasmic tail (p.P5L, p.S50P, p.E60K, and p.R75Q) and four in the first transmembrane segment of membrane-spanning domain 1 (p.G85E/V, p.Y89C, and p.E92K). Immunoblot analysis revealed that p.S50P, p.E60K, p.G85E/V, and p.E92K produced only core-glycosylated proteins. Immunofluorescence and whole cell patch-clamp confirmed intracellular retention, thus reflecting a defect of CFTR folding and/or trafficking. In contrast, both p.R75Q and p.Y89C had a glycosylation pattern and a subcellular distribution comparable to the wild-type CFTR, while the percentage of mature p.P5L was considerably reduced, suggesting a major biogenesis flaw on this channel. Nevertheless, whole-cell chloride currents were recorded for all three variants. Single-channel patch-clamp analyses revealed that the channel activity of p.R75Q appeared similar to that of the wild-type CFTR, while both p.P5L and p.Y89C channels displayed abnormal gating. Overall, our results predict a major impact of the CFTR missense variants analyzed, except p.R75Q, on the CF phenotype and highlight the importance of the CFTR N-terminus on channel physiology.

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133 Genotype^Phenotype Correlation in the N-Terminal CFTR MissenseVariants Under StudyÃ Missense varianta Phenotype Second allele (number of patients)b p.P5L CF p.F508del (1), p.P205S (1) p.S50P CBAVD p.F508del (1), p.E115del (1) p.E60K CF p.G542X (1), p.I507del (1) p.R75Q HT p.F508del (3), p.E725K (1) B p.R347H (1), p.R75Q (1), n.i. (4) Br c.1584G4A (2), c.1210-7_1210-6delTT (1), n.i.(3) NT p.F508del (1) CP c.1584G4A (1), n.i. (3) MI n.i. (1) CUAVD n.i. (2) OZ n.i. (2) Normal p.R75Q (1), c.2052_2053insA (1), n.i. (1) p.G85E CF p.F508del (8), p.G542X (2), p.I507del (1), c.580-1G4T (1), p.G85E (1), c.1477_ 1478delCA (1) CBAVD p.G576A (1) HT p.L997F (1),WT (1) p.G85V CF p.F508del (2), p.G542X (2), p.Y1092X (1), c.265715G4A (1), p.A1006E, c.1210-7_1210- 6delTT (1), n.i. (1) p.Y89C CF n.i. (1)c p.E92K CF p.F508del (2), p.Q890X (1), p.L206W (1) CBAVD c.1210-7_1210-6delTT (1) ÃThe recommendations for mutation nomenclature (www.hgvs.org/mutnomen/) were used to name CFTR gene sequence variations at both the nucleotide level and the protein level. 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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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

[hide] Independent contribution of common CFTR variants t... Pancreas. 2010 Mar;39(2):209-15. de Cid R, Ramos MD, Aparisi L, Garcia C, Mora J, Estivill X, Farre A, Casals T
Independent contribution of common CFTR variants to chronic pancreatitis.
Pancreas. 2010 Mar;39(2):209-15., [PMID:19812525]

Abstract [show]
OBJECTIVE: We have assessed whether CFTR gene has a major impact on chronic pancreatitis (CP) pathogenesis than that provided by the CFTR mutations. For this aim, we have evaluated clinical parameters, CFTR mutations, and 3 potential regulatory CFTR variants (coding single-nucleotide polymorphisms): c.1540A>G, c.2694T>G, and c.4521G>A. METHODS: CFTR gene analysis was performed in a cohort of 136 CP patients and 93 controls from Spanish population using current scanning techniques (single-strand conformation polymorphism/heteroduplex, denaturing gradient gel electrophoresis, and denaturing high-performance liquid chromatography) and direct sequencing. RESULTS: A higher frequency of CFTR mutations were observed in patients (39%) than in controls (15%; P < or = 0.001), differences being mostly attributable to the prevalence of the cystic fibrosis (CF)-causing mutations (P = 0.009). The analysis of variants has shown statistically significant differences between patients and controls for c.4521G>A (Pcorrected = 0.036). Furthermore, the multi-marker analysis revealed that the 1540A;2694G;4521A (AGA) haplotype was more prevalent in CP than controls (Pcorrected = 0.042). Remarkably, this association was unrelated to CF-causing mutations (P = 0.006). CONCLUSIONS: Our results corroborate the higher susceptibility of CF carriers to CP and, furthermore, suggest that the AGA haplotype could contribute to an increased risk in the development of CP irrespective of other CF-causing mutations.

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38 Scanning Methodology Applied in CFTR Gene Analysis Amplicon Name Fragment Size, bp Control Set (n = 93) Patient Set 1 (n = 68) Patient Set 2 (n = 68) Control Sequence Exon 1 192 SSCP/HD SSCP/HD dHPLC 125G9C Exon 2 334 SSCP/HD SSCP/HD dHPLC 296+3insT Exon 3 309 DGGE DGGE dHPLC G85V Exon 4 436 SSCP/HD SSCP/HD dHPLC R117H Exon 5 466 DGGE DGGE dHPLC R170H Exon 6a 345 SSCP/HD SSCP/HD dHPLC L206W Exon 6b 331 SSCP/HD SSCP/HD SSCP/HD TTGA 6/7 Exon 7 410 SSCP/HD SSCP/HD dHPLC R334W Exon 8 328 DGGE DGGE dHPLC 1341+28C9T Exon 9 375 DGGE DGGE DGGE 7T/9T Exon 10 493 SSCP/HD SSCP/HD SSCP/HD F508del; 1540A/A Exon 11 322 DGGE DGGE dHPLC S549R Exon 12 426 DGGE DGGE dHPLC G576A Exon 13a 532 SSCP/HD SSCP/HD dHPLC R668C Exon 13b 498 SSCP/HD SSCP/HD dHPLC I807M Exon 14a 284 DGGE DGGE DGGE 2694T9G Exon 14b 211 DGGE DGGE dHPLC 2789+5G9A Exon 15 487 DGGE DGGE dHPLC D924N Exon 16 294 SSCP/HD SSCP/HD dHPLC 3041-71G9C Exon 17a 294 SSCP/HD SSCP/HD dHPLC L997F Exon 17b 463 DGGE DGGE dHPLC 3272-26A9G Exon 18 451 DGGE DGGE dHPLC N1148K Exon 19 588 SSCP/HD SSCP/HD SSCP/HD 3601-65C9A Exon 20 471 DGGE DGGE dHPLC W1282X Exon 21 477 DGGE DGGE DGGE 4029G9A Exon 22 339 SSCP/HD SSCP/HD dHPLC Q1352H Exon 23 249 DGGE DGGE dHPLC 4374+13A9G Exon 24 362 SSCP/HD SSCP/HD SSCP/HD 4521G9A Control set, general population series analyzed; patient set 1, previous patient series reported in 2004; and patient set 2, new patient series analyzed in this study. Login to comment
74 To simplify, as previously mentioned, the 4 CFTR-related disorderYassociated mutations, 5T-12TG, L997F, R297Q, and D443Y-G576A-R668C, have been grouped together with the CF-causing mutations in front of other CFTR mutations without or unknown clinical relevance13 (Table 3). Login to comment
81 CFTR Genotypes in Chronic Pancreatitis Patients and General Population Pt/Phenotype CFTR Genotype Pt/Phenotype CFTR Genotype 1/ACP F508del† , I1027T/j 19/ACP* R668C/j 2/ACP* F508del† /j 20/ACP D836Y/j 3/ACP F508del† , I1027T/Y1014C 21/ACP* L997F† /j 4/ACP F508del† /1716G9A 22/ACP* R1162L/j 5/ACP* F508del† /1716G9A 23/ACP 5T-11TG/j 6/ACP* F508del† /S1235R 24/ACP 5T-11TG/j 7/ACP G542X† /j 25/ACP 5T-11TG/j 8/ACP* W1282X† /j 26/ACP* 5T-11TG/j 9/ACP 5T-12TG† /5T-11TG 27/ACP* 5T-11TG/j 10/ACP* 5T-12TG† /j 28/ACP 1716G9A/4374+13A9G 11/ACP R75Q/j 29/ACP 1716G9A/j 12/ACP R75Q/j 30/ACP 1716G9A/j 13/ACP Y122C/Y122C 31/ACP 1716G9A/j 14/ACP* R170C/j 32/ACP 1716G9A/j 15/ACP* R258G/j 33/ACP* 1716G9A/j 16/ACP* M281T/j 34/ACP 2377C9T/j 17/ACP* R297Q† /- 35/ACP* 2377C9T/j 18/ACP T351S/- 36/ACP 3499+37G9A/j 1/ICP F508del† /- 10/ICP* 1716G9A/j 2/ICP D443Y,G576A,R668C† /j 11/ICP* 1716G9A/j 3/ICP* D443Y,G576A,R668C† /j 12/ICP 1716G9A/j 4/ICP* P205S† /j 13/ICP* 1716G9A/j 5/ICP* L997F† /j 14/ICP* 1716G9A/j 6/ICP* R170H/1716G9A 15/ICP* 1716G9A/j 7/ICP 109A9G/j 16/ICP* 1716G9A/j 8/ICP* 5T-11TG/j 17/ICP 1716G9A/j 9/ICP* 5T-11TG/j 1/GP 5T-12TG† /j 8/GP 1716G9A/j 2/GP 5T-12TG† /j 9/GP 1716G9A/j 3/GP A534E† /j 10/GP 1716G/A/j 4/GP 5T-11TG/V562I 11/GP 1716G9A/j 5/GP 5T-11TG/j 12/GP 1716G9A/j 6/GP 5T-11TG/j 13/GP 3690A9G/j 7/GP 1716G9A/j 14/GP 3690A9G/j Corresponding mutation nomenclature (Human Genome Variation Society and Cystic Fibrosis Mutation Data Base): c.1584G9A (1716G9A), c.1210-7_1210-6delTT (5T), 1210-34_1210-13TG (11TG), g.-23A9G (109A9G), c.4242+13A9G (4374+13A9G), c.2245C9T (2377C9T), c.3367+ 37G9A (3499+37G9A), and c.3558A9G (3690A9G). Login to comment
82 *Patients previously reported.12 † CF-causing mutations and mutations associated to CFTR-related disorders (5T-12TG, L997F, R297Q, and D443Y-G576A-R668C). Login to comment

[hide] Functional properties and evolutionary splicing co... Nucleic Acids Res. 2010 Jan;38(2):647-59. Epub 2009 Nov 12. Haque A, Buratti E, Baralle FE
Functional properties and evolutionary splicing constraints on a composite exonic regulatory element of splicing in CFTR exon 12.
Nucleic Acids Res. 2010 Jan;38(2):647-59. Epub 2009 Nov 12., [PMID:19910374]

Abstract [show]
In general, splicing regulatory elements are defined as Enhancers or Silencers depending on their positive or negative effect upon exon inclusion. Often, these sequences are usually present separate from each other in exonic/intronic sequences. The Composite Exonic Splicing Regulatory Elements (CERES) represent an extreme physical overlap of enhancer/silencer activity. As a result, when CERES elements are mutated the consequences on the splicing process are difficult to predict. Here, we show that the functional activity of the CERES2 sequence in CFTR exon 12 is regulated by the binding, in very close proximity to each other, of several SR and hnRNP proteins. Moreover, our results show that practically the entire exon 12 sequence context participate in its definition. The consequences of this situation can be observed at the evolutionary level by comparing changes in conservation of different splicing elements in different species. In conclusion, our study highlights how it is increasingly difficult to define many exonic sequences by simply breaking them down in isolated enhancer/silencer or even neutral elements. The real picture is close to one of continuous competition between positive and negative factors where affinity for the target sequences and other dynamic factors decide the inclusion or exclusion of the exon.

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137 Western blot analysis of recovered proteins after pulldown of two naturally occurring nonsense CFTR mutations (G48C/G576A and A51T/Y577F) compared with CFTR Ex. 12 wild type. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... Am J Respir Crit Care Med. 2010 May 15;181(10):1078-84. Epub 2010 Feb 18. Bienvenu T, Sermet-Gaudelus I, Burgel PR, Hubert D, Crestani B, Bassinet L, Dusser D, Fajac I
Cystic fibrosis transmembrane conductance regulator channel dysfunction in non-cystic fibrosis bronchiectasis.
Am J Respir Crit Care Med. 2010 May 15;181(10):1078-84. Epub 2010 Feb 18., 2010-05-15 [PMID:20167849]

Abstract [show]
RATIONALE: Although in patients with diffuse bronchiectasis (DB) and a normal sweat test the presence of one mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is frequently observed, its pathogenic role in the development of DB remains unclear. OBJECTIVES: To evaluate the association between CFTR heterozygosity and CFTR protein dysfunction in the airways of patients with DB. METHODS: Nasal potential difference was measured in 122 patients with DB of unknown origin and with a normal sweat test (Cl(-) < 60 mmol/L). They were classified according to the presence of CFTR mutations: zero (85 patients), one (22 patients), or two mutations (15 patients). Control groups comprised 26 healthy subjects, 38 obligate heterozygotes for CFTR, and 92 patients with classic cystic fibrosis (CF) with an abnormal sweat test (Cl(-) > or = 60 mmol/L). Patients classified as mild-CF were carrying at least one mild mutation and patients classified as severe-CF were homozygous for the F508del mutation. MEASUREMENTS AND MAIN RESULTS: There was a continuum of airway CFTR dysfunction in the study population as shown by nasal potential difference measurements, ranging from normal values in healthy subjects, to intermediate values in subjects with DB, to highly abnormal values in subjects classified as severe-CF. This continuum of airway CFTR dysfunction was thus strongly associated with defects in the CFTR gene. Moreover, among patients with DB, a similar continuum in intermediate nasal potential difference was identified that was associated with the bearing of zero, one, or two CFTR mutations. These electrophysiological phenotypes and CFTR genotypes were also associated with the clinical phenotype, as shown by the frequency of Staphylococcus aureus and Pseudomonas aeruginosa bronchial colonization. CONCLUSIONS: Our study supports the hypothesis that a unique CFTR mutation may have pathogenic consequences in patients with DB.

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82 GENOTYPE AND PHENOTYPE OF PATIENTS WITH DIFFUSE BRONCHIECTASIS BEARING TWO CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR MUTATIONS Patient No. Age (yr) Sex (M/F) CFTR Mutations Sweat Cl2 (mmol/L) Basal PD (mV) NPD Index Age at Onset (yr) FEV1 (% pred) Bacteria Colonization 1 55 F F508del/D1152H 19 219 1.00 54 99 Sa 2 71 F F508del/G576A-R668C 29 223 0.44 70 114 None 3 24 M G542X/3849110kbCT 52 224 1.22 10 78 Pa 4 41 F 394delTT/D1152H 19 225 0.30 41 89 Sa 5 31 M 3849110kbC.T/3849110kbC.T 35 230 0.64 2 30 Sa/Pa 6 74 F G542X/S912L 40 233 0.19 60 106 None 7 50 M W1282X/D1152H 35 236 1.00 10 32 Pa 8 42 F F508del/D1152H 13 240 0.68 30 32 Pa 9 56 F F508del/IVS8-5T 30 242 0.70 10 70 None 10 45 F 394delTT/D1152H 25 242 0.71 18 62 Sa/Pa 11 74 F W1282X/D1152H 25 244 0.66 12 56 Pa 12 23 F S1206X/D1152H 19 244 0.68 13 107 None 13 41 F R553X/R851L-T351S 31 248 0.50 35 72 Pa 14 58 M F508del/R117H-7T 46 251 0.61 45 35 Sa/Pa 15 53 F F508del/R347H 49 258 0.63 40 77 Pa Definition of abbreviations: Cl2 5 chloride; F 5 female; M 5 male; NPD index 5 nasal potential difference index 5 e(response to øCl2 and iso/response to amil); a cut off . Login to comment

[hide] Genetic testing in pancreatitis. Gastroenterology. 2010 Jun;138(7):2202-6, 2206.e1. Epub 2010 Apr 20. Ooi CY, Gonska T, Durie PR, Freedman SD
Genetic testing in pancreatitis.
Gastroenterology. 2010 Jun;138(7):2202-6, 2206.e1. Epub 2010 Apr 20., [PMID:20416310]

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53 Interpretation of Mutations Requires an Understanding of Their Functional Consequences Mutation group Reported mutations Complex allele: These mutations are recognized to occur on a single allele R117H ϩ T G576A ϩ R668C F508del ϩ I1027T Benign sequence alterations: These mutations have no known clinical consequence R74Q R297Q R74W 621 * 25 AϾG 3500-19 CϾT T164S C855I I1139V CFTR-related disorder associated: These mutations have been described in individuals with CF-like single organ disease (such as pancreatitis, sinopulmonary disease, or obstructive azoospermia), but do not fulfill the diagnostic criteria for CF 5T R117H D1270N L320V Q1352H 1818-18 GϾA S1235R CF causing F508del Q1476X R553X K710X G542X G551D F311L 2789-5 GϾA 2183AAϾG 711ϩ3 AϾG 3849ϩ10kb CϾT 1341ϩ1GϾA D1152Ha F1074La R553X Unknown clinical consequence F575Y L1260P G194R G1069R L997F K598E F834L R785Q To illustrate this point, mutations identified by extensive mutation testing in a cohort of patients with recurrent acute or chronic pancre- atitis14 are listed according to their clinical consequences (based on current consensus guidelines13 and functional and/or clinical reports; available: http://www.genet.sickkids.on.ca). Login to comment

[hide] Clinical phenotype and genotype of children with b... Am J Respir Crit Care Med. 2010 Oct 1;182(7):929-36. Epub 2010 Jun 10. Sermet-Gaudelus I, Girodon E, Sands D, Stremmler N, Vavrova V, Deneuville E, Reix P, Bui S, Huet F, Lebourgeois M, Munck A, Iron A, Skalicka V, Bienvenu T, Roussel D, Lenoir G, Bellon G, Sarles J, Macek M, Roussey M, Fajac I, Edelman A
Clinical phenotype and genotype of children with borderline sweat test and abnormal nasal epithelial chloride transport.
Am J Respir Crit Care Med. 2010 Oct 1;182(7):929-36. Epub 2010 Jun 10., 2010-10-01 [PMID:20538955]

Abstract [show]
RATIONALE: The diagnosis of cystic fibrosis (CF) is based on a characteristic clinical picture in association with a sweat chloride (Cl(-)) concentration greater than 60 mmol/L or the identification of two CF-causing mutations. A challenging problem is the significant number of children for whom no definitive diagnosis is possible because they present with symptoms suggestive of CF, a sweat chloride level in the intermediate range between 30 and 60 mmol/L, and only one or no identified CF-causing mutation. OBJECTIVES: To investigate the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in the airways of children with intermediate sweat tests and inconclusive genetic findings in correlation with clinical phenotype and genotype. METHODS: We developed a composite nasal potential difference (NPD) diagnostic score to discriminate patients with CF from non-CF patients. We tested NPD in 50 children (age, 6 mo to 18 yr) with equivocal diagnoses and correlated the NPD diagnostic score with clinical phenotypes and genotypes. MEASUREMENTS AND MAIN RESULTS: Fifteen of the 50 children had NPD scores in the CF range. Eight of the 15 carried two CFTR mutations compared with only 5 of the 35 children with normal NPD scores (P = 0.01). They were significantly younger at evaluation and had recurrent lower respiratory tract infections, chronic productive coughs, and chronic Staphylococcus aureus colonization significantly more often than the 35 children with normal NPD results. CONCLUSIONS: Evaluation of CFTR function in the nasal epithelium of children with inconclusive CF diagnoses can be a useful diagnostic tool and help clinicians to individualize therapeutic strategy.

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162 CLINICAL CHARACTERISTICS OF CHILDREN WITH EQUIVOCAL DIAGNOSES AND NASAL POTENTIAL DIFFERENCE DIAGNOSTIC SCORE <0.27 Pt Mutation Age (yr) NPD Score Sweat Cl2 Chronic CF Pulmonary Disease CF Pathogens Airway Obstruction CF Lung Imaging FEV1 (%) BMI Others 1 F508del/S977F A-D 8 0.181 43 RLRTI, chronic productive cough S. aureus No Bronchiectasis 80 14.5 No Bronchial thickening Atelectasis 2 0/0 4 0.121 43 No S. aureus Yes Air trapping NA 13 Pancreatic extracts 0-0 Bronchial thickening 3 0/0 15 20.032 46 RLRTI S. aureus, P. aeruginosa Yes Air trapping 74 14 Polyposis 0-0 Bronchiectasis 4 F508del/0 2 20.249 57 RLRTI P. aeruginosa Yes Air trapping NA 16 No A-0 5 N1303K/(TG12)T5 11.8 20.263 47 RLRTI S. aureus, P. aeruginosa No Bronchial thickening ND 20 No A-B 6 F508del/L206W 5.9 20.278 40 RLRTI S. aureus No Bronchial thickening 115 22 Chronic pancreatitis A-AB 7 R668C/0 15 20.403 40 RLRTI None Yes Bronchiectasis 112 20 No B-0 Air trapping 8 F508del/L997F A-B 1 20.594 38 RLRTI, chronic productive cough P. aeruginosa No Bronchial thickening NA 16 CF hepatopathy 9 G576A;R668C/S1235R 8 20.659 31 0 None Wheezing Normal 100 20 No B-B 10 G542X/0 5 20.718 49 RLRTI, chronic productive cough S. aureus No Bronchial thickening NA 18 No A-0 11 0/0 7 20.742 37 RLRTI None No Normal 106 18 No 0-0 12 F508del/D110E 16 20.777 50 No S. aureus No No 100 21 No A-AB 13 F508del/R1070W 7 21.006 40 RLRTI S. aureus Wheezing Bronchial thickening 110 14 No A-AB 14 F508del-L467F/0 12 21.897 55 RLRTI, chronic productive cough S. aureus No Bronchiectasis 109 17 Pansinusitis A-0 15 F508del/H1054D 9 22.327 59 RLRTI, chronic productive cough S. aureus No Bronchial thickening 100 20 DIOS A-D Definition of abbreviations: A, B, AB, and D: A 5 CF-causing mutation; B 5 mutation that results in a CFTR-RD (clinical entities associated with CFTR mutations that do not meet the current diagnostic criteria for CF); AB 5 wide-spectrum mutation that may belong to either group A or group B; D 5 mutation of uncertain clinical relevance; BMI 5 body mass index; CF 5 cystic fibrosis; CFTR 5 gene encoding cystic fibrosis transmembrane conductance regulator; DIOS 5 distal intestinal obstructive syndrome; NA 5 not applicable; ND 5 not determined; NPD 5 nasal potential difference; P. aeruginosa 5 Pseudomonas aeruginosa; Pt 5 patient; RLRTI 5 recurrent lower respiratory tract infection; S. aureus 5 Staphylococcus aureus. 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

[hide] p.Ser1235Arg should no longer be considered as a c... Eur J Hum Genet. 2011 Jan;19(1):36-42. Epub 2010 Aug 18. Rene C, Paulet D, Girodon E, Costa C, Lalau G, Leclerc J, Cabet-Bey F, Bienvenu T, Blayau M, Iron A, Mittre H, Feldmann D, Guittard C, Claustres M, Georges M
p.Ser1235Arg should no longer be considered as a cystic fibrosis mutation: results from a large collaborative study.
Eur J Hum Genet. 2011 Jan;19(1):36-42. Epub 2010 Aug 18., [PMID:20717170]

Abstract [show]
Among the 1700 mutations reported in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, a missense mutation, p.Ser1235Arg, is a relatively frequent finding. To clarify its clinical significance, we collected data from 104 subjects heterozygous for the mutation p.Ser1235Arg from the French CF network, addressed for various indications including classical CF, atypical phenotypes or carrier screening in subjects with or without a family history. Among them, 26 patients (5 having CF, 10 CBAVD (congenital bilateral absence of the vas deferens) and 11 with CF-like symptoms) and 14 healthy subjects were compound heterozygous for a second CFTR mutation. An exhaustive CFTR gene analysis identified a second mutation in cis of p.Ser1235Arg in all CF patients and in 81.8% CBAVD patients. Moreover, epidemiological data from >2100 individuals found a higher frequency of p.Ser1235Arg in the general population than in CF or CBAVD patients. These data, added to the fact that in silico analysis and functional assays suggest a benign nature of this substitution, give several lines of evidence against an association of p.Ser1235Arg with CF or CBAVD.

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79 In the last case, the fetus carried the complex allele (p.Gly576Ala; p.Arg668Cys), considered as a mild mutation involved in CBAVD or disseminated bronchiectasis phenotypes in adults.29-31 Although the fetus presented hyperechogenic fetal bowel, the parents were reassured regarding the risk of classical CF. Login to comment

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

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

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

[hide] 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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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
92 Two peculiar mutations that occurred in both populations, c.1584GtoA (1716GtoA legacy name) and p.R75Q, have been generally regarded as benign sequence variations28 (www.genet.sickkids. on.ca) but repeatedly show association to CF-related diseases, pancreatitis,29-31 and some patients with atypical CF.32 Two individual nonsynonymous sequence changes, p.R668C and p.I148T, were identified with CFTR full sequencing in one control each but without additional mutations found in cis (p.D443Y ϩ p.G576A and c.3067del6 [ie, 3199del6], respectively). Login to comment

[hide] Comprehensive description of CFTR genotypes and ul... Hum Genet. 2011 Apr;129(4):387-96. Epub 2010 Dec 24. de Becdelievre A, Costa C, Jouannic JM, LeFloch A, Giurgea I, Martin J, Medina R, Boissier B, Gameiro C, Muller F, Goossens M, Alberti C, Girodon E
Comprehensive description of CFTR genotypes and ultrasound patterns in 694 cases of fetal bowel anomalies: a revised strategy.
Hum Genet. 2011 Apr;129(4):387-96. Epub 2010 Dec 24., [PMID:21184098]

Abstract [show]
Fetal bowel anomalies may reveal cystic fibrosis (CF) and the search for CF transmembrane conductance regulator (CFTR) gene mutations is part of the diagnostic investigations in such pregnancies, according to European recommendations. We report on our 18-year experience to document comprehensive CFTR genotypes and correlations with ultrasound patterns in a series of 694 cases of fetal bowel anomalies. CFTR gene analysis was performed in a multistep process, including search for frequent mutations in the parents and subsequent in-depth search for rare mutations, depending on the context. Ultrasound patterns were correlated with the genotypes. Cases were distinguished according to whether they had been referred directly to our laboratory or after an initial testing in another laboratory. A total of 30 CF fetuses and 8 cases compatible with CFTR-related disorders were identified. CFTR rearrangements were found in 5/30 CF fetuses. 21.2% of fetuses carrying a frequent mutation had a second rare mutation, indicative of CF. The frequency of CF among fetuses with no frequent mutation was 0.43%. Correlation with ultrasound patterns revealed a significant frequency of multiple bowel anomalies in CF fetuses. The results emphasize the need to search for rearrangements in the diagnosis strategy of fetal bowel anomalies. The diagnostic value of ultrasound patterns combining hyperechogenic bowel, loop dilatation and/or non-visualized gallbladder reveals a need to revise current strategies and to offer extensive CFTR gene testing when the triad is diagnosed, even when no frequent mutation is found in the first-step analysis.

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186 [G576A;R668C] c.[2538G[A]? Login to comment
195 [G576A;R668C] c.[1521_1523delCTT]? Login to comment
276 [Asp443Tyr; Gly576Ala;Arg668Cys], c.[1327G[T;1727G[C;2002C[T]). 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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137 [G576A;R668C], p. Login to comment

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

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

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

[hide] Complete mutational screening of the CFTR gene in ... Hum Genet. 1998 Dec;103(6):718-22. Bombieri C, Benetazzo M, Saccomani A, Belpinati F, Gile LS, Luisetti M, Pignatti PF
Complete mutational screening of the CFTR gene in 120 patients with pulmonary disease.
Hum Genet. 1998 Dec;103(6):718-22., [PMID:9921909]

Abstract [show]
In order to determine the possible role of the cystic fibrosis transmembrane regulator (CFTR) gene in pulmonary diseases not due to cystic fibrosis, a complete screening of the CFTR gene was performed in 120 Italian patients with disseminated bronchiectasis of unknown cause (DBE), chronic bronchitis (CB), pulmonary emphysema (E), lung cancer (LC), sarcoidosis (S) and other forms of pulmonary disease. The 27 exons of the CFTR gene and their intronic flanking regions were analyzed by denaturing gradient gel electrophoresis and automatic sequencing. Mutations were detected in 11/23 DBE (P = 0.009), 7/25 E, 5/27 CB, 5/26 LC, 5/8 S (P = 0.013), 1/4 tuberculosis, and 1/5 pneumonia patients, and in 5/33 controls. Moreover, the IVS8-5T allele was detected in 6/25 E patients (P = 0.038). Four new mutations were identified: D651N, 2377C/T, E826K, and P1072L. These results confirm the involvement of the CFTR gene in disseminated bronchiectasis of unknown origin, and suggest a possible role for CFTR gene mutations in sarcoidosis, and for the 5T allele in pulmonary emphysema.

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62 Five mutations (G576A, R668C, R74W, R31C, and I506V) are not thought to be the cause of CF (CFGAC website): three of them (G576A, R668C, and R74W) have been found in CBAVD patients (Anguiano et al. 1992; Chillon et al. 1995; Mercier et al. 1995; Verlingue et al. 1996), R31C was described in a DBE patient (Girodon et al. 1997), and I506V was found in the normal allele in the father of a CF child (Ghanem et al. 1994). Login to comment
67 Two compound heterozygotes were observed: G576A-R668C/L997F, and ∆F508/L997F. Login to comment
88 of cases CFTR gene PolyTb status tested mutationa DBE 23 1 G576A-R668C/L997F 7/9 1 ∆F508/L997F 9/9 1 ∆F508/- 7/9 1 R1066C/- 5/7 1 3667ins4/- 5/7 1 R75Q/- 7/7 1 M1137V/- 7/7 1 -/- 5/5 3 -/- 5/7 10 -/- 7/7 2 -/- 7/9 CB 27 1 P111L/- 7/7 1 R117H/- 7/7 1 E585X/- 7/7 1 P1072L/- 7/7 1 -/- 5/7 15 -/- 7/7 6 -/- 7/9 1 -/- 9/9 E 25 1 R668C/- 7/7 6 -/- 5/7 16 -/- 7/7 6 -/- 7/9 S 8 1 E826K/- 7/7 1 ∆F508/- 7/9 1 4382delA/- 7/7 1 L997F/- 7/9 1 V754M/- 7/9 3 -/- 7/7 LC 26 1 I148T/- 5/7 1 D1270N-R74W 5/7 1 D651N/- 7/7 1 Y301C/- 7/7 1 -/- 5/7 16 -/- 7/7 5 -/- 7/9 TB 4 1 -/- 5/7 1 -/- 7/7 2 -/- 7/9 Pneumonia 5 4 -/- 7/7 1 -/- 5/7 Pnx 2 2 -/- 7/7 Controls 68 1 L997F/- 7/9 1 R31C/- 7/7 1 I506V/- 5/7 1 -/- 5/7 1 -/- 5/9 23 -/- 7/7 4 -/- 7/9 1 -/- 9/9 2 ? Login to comment

[hide] The role of common single-nucleotide polymorphisms... Hum Mutat. 2004 Aug;24(2):120-9. Steiner B, Truninger K, Sanz J, Schaller A, Gallati S
The role of common single-nucleotide polymorphisms on exon 9 and exon 12 skipping in nonmutated CFTR alleles.
Hum Mutat. 2004 Aug;24(2):120-9., [PMID:15241793]

Abstract [show]
Classic cystic fibrosis (CF) is caused by two loss-of-function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, whereas patients with nonclassic CF have at least one copy of a mutant gene that retains partial function of the CFTR protein. In addition, there are several other phenotypes associated with CFTR gene mutations, such as idiopathic chronic pancreatitis. In CFTR-associated disorders and in nonclassic CF, often only one CFTR mutation or no CFTR mutations can be detected. In this study, we screened 23 patients with CFTR-associated disorders for CFTR mutations by complete gene testing and quantitative transcript analysis. Mutations were found in 10 patients. In cells from respiratory epithelium, we detected aberrant splicing of CFTR mRNA in all investigated individuals. We observed a highly significant association between the presence of coding single-nucleotide polymorphisms (coding SNPs, or cSNPs) and increased skipping of exon 9 and 12. This association was found both in patients and in normal individuals carrying the same cSNPs. The cSNPs c.1540A>G, c.2694T>G, and c.4521G>A may have affected pre-mRNA splicing by changing regulatory sequence motifs of exonic splice enhancers, leading to lower amounts of normal transcripts. The analysis of CFTR exons indicated that less frequent and weak exonic splicing enhancer (ESE) motifs make exon 12 vulnerable to skipping. The number of splice variants in individuals with cSNPs was similar to previously reported values for the T5 allele, suggesting that cSNPs may enhance susceptibility to CFTR related diseases. In addition, cSNPs may be responsible for variation in the phenotypic expression of CFTR mutations. Quantitative approaches rather than conventional genomic analysis are required to interpret the role of cSNPs.

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184 Sequence variations (i.e., p.D565G and p.G576A) in the newly identified composite exonic regulatory element of splicing (CERES) of exon 12 [Pagani et al., 2003b] were excluded by SSCP and sequence analysis. Login to comment

[hide] Molecular evaluation of CFTR sequence variants in ... Int J Androl. 2005 Oct;28(5):284-90. Larriba S, Bonache S, Sarquella J, Ramos MD, Gimenez J, Bassas L, Casals T
Molecular evaluation of CFTR sequence variants in male infertility of testicular origin.
Int J Androl. 2005 Oct;28(5):284-90., [PMID:16128988]

Abstract [show]
Although the involvement of the CFTR gene has been well established in congenital agenesia of vas deferens, its role in non-obstructive (NOb) infertility is still a matter of debate. In order to definitively define the involvement of the CFTR gene in spermatogenic impairment and a potential synergistic contribution to known genetic and clinical factors, genetic variants in the entire coding sequence and the immediately flanking regions of the CFTR gene, along with a thorough clinical evaluation, were analysed in 83 NOb infertile patients and 87 clinically well-defined fertile individuals as controls. The results of our study showed no statistical difference between CFTR carrier frequency in the infertile and fertile population. Specifically, the IVS8-6(5T) allele carrier frequency was similar in NOb infertile patients when compared with fertile men, but it is noteworthy that, when fertile men were classified into having optimal and suboptimal fertility, no 5T allele was found among the 35 men with optimal fertility parameters. In conclusion, extensive CFTR analysis in infertile individuals and fertile population as adequate control definitively excludes the involvement of the CFTR gene variants in sperm production and stresses the importance of carefully identifying those individuals with obstructive defects, in whom CFTR screening will be beneficial.

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51 CFTR analysis We identified 14 different, potential disease-causing CFTR sequence variants, 11 of them are translated into missense amino acid changes (p.R75Q, p.P111L, p.R117H, p.I148T, p.R334W, p.M348K, p.G576A, p.R668C, p.D1270N, p.S1235R and p.S1426F), one deletion (p.F508del) and two alleles affecting exon splicing [IVS8-6(5T), c.1716G>A] in 30 of 83 infertile patients (Table 1) giving a frequency of 36.1%. Login to comment
53 Thirteen CFTR gene sequence variants [p.R75Q, p.I148T, p.T351S, p.F508del, p.G576A, p.R668C, p.E725K, p.V754M, p.D836Y, p.L997F, p.S1235R, IVS8-6(5T) and c.1716G>A] were determined in 11 F1 and 15 F2 individuals (Table 1) giving a frequency of 29.9%. Login to comment
72 Description of genetic abnormalities and other risk factors of infertile and fertile CFTR carrier individuals No. Phenotype CFTR genotype Associated factors Testicular histologya b c Infertile individuals 1 NOb (SO) p.R75Q No Severe hypospermatogenesis 2 NOb (SO) p.R75Q No nd 3 NOb (A) p.P111L AZFb,c del Sertoli cell only 4 NOb (A) p.R117H AZFc del Severe hypospermatogenesis 5 NOb (SO) p.I148T No Severe hypospermatogenesis 6 NOb (A) p.R334W No Primary spermatocyte arrest 7 NOb (SO) p.M348K UV grade III Primary spermatocyte arrest 8 NOb (A) p.F508del No Sertoli cell only 9 NOb (A) p.F508del No Primary spermatocyte arrest 10 NOb (A) p.G576A, p.R668C No Severe hypospermatogenesis, Leydig cell hyperplasia 11 NOb (SO) p.G576A, p.R668C No Primary spermatocyte arrest (unilateral) 12 NOb (SO) p.G576A, p.R668C No Severe hypospermatogenesis 13 NOb (A) p.R668C UC Sertoli cell-only (incomplete) 14 NOb (SO) p.D1270N No nd 15 NOb (SO) p.S1235R No Severe hypospermatogenesis 16 NOb (SO) p.S1426F* UC Sertoli cell only 17 NOb (A) (T)5-(TG)12 No Severe hypospermatogenesis, Sertoli cell only (80%) 18 NOb (A) (T)5-(TG)12 No Sertoli cell only 19 NOb (SO) (T)5-(TG)11 UV grade III Bilateral moderate hypospermatogenesis 20 NOb (SO) (T)5-(TG)11 UV grade II Severe hypospermatogenesis 21 NOb (A) (T)5-(TG)11 No nd 22 NOb (SO) c.1716 G>A Dysplasia SV Severe hypospermatogenesis, Sertoli cell only (95%) 23 NOb (A) c.1716 G>A No nd 24 NOb (A) c.1716 G>A No Primary spermatocyte arrest (bilateral) 25 NOb (SO) c.1716 G>A No Sertoli cell only (95%) 26 NOb (SO) c.1716 G>A No Severe hypospermatogenesis 27 NOb (SO) c.1716 G>A UV grade III Severe hypospermatogenesis 28 NOb (SO) c.1716 G>A No nd 29 NOb (SO) c.1716 G>A No nd 30 NOb (SO) c.1716 G>A AZFc del Severe hypospermatogenesis Fertile individuals 1 F1 p.R75Q No nd 2 F1 p.F508del No nd 3 F1 p.F508del No nd 4 F1 p.G576A, p.R668C/ c.1716 G>A No nd 5 F1 p.D836Y No nd 6 F1 p.S1235R/c.1716 G>A No nd 7 F1 c.1716 G>A No nd 8 F1 c.1716 G>A No nd 9 F1 c.1716 G>A No nd 10 F1 c.1716 G>A No nd 11 F1 c.1716 G>A No nd 12 F2 p.R75Q No nd the expected CF carrier frequency in the local population (Van der Ven et al., 1996; Larriba et al., 2001; Dohle et al., 2002) or with the general population (Jakubiczka et al., 1999; Pallares-Ruiz et al., 1999; Ravnik-Glavac et al., 2001) and not normospermic fertile individuals, the latter considered as adequate controls. Login to comment
78 Some variants affect normal mRNA splicing leading to skipping of exon 9 [IVS8-6(5T) (Chu et al., 1993)], exon 10 [c.1716G>A (p.E528E) (Dork et al., 1997)] and exon 12 [p.G576A and p.R668C (Pagani et al., 2003]. Login to comment

[hide] Spectrum of mutations in the CFTR gene in cystic f... Ann Hum Genet. 2007 Mar;71(Pt 2):194-201. Alonso MJ, Heine-Suner D, Calvo M, Rosell J, Gimenez J, Ramos MD, Telleria JJ, Palacio A, Estivill X, Casals T
Spectrum of mutations in the CFTR gene in cystic fibrosis patients of Spanish ancestry.
Ann Hum Genet. 2007 Mar;71(Pt 2):194-201., [PMID:17331079]

Abstract [show]
We analyzed 1,954 Spanish cystic fibrosis (CF) alleles in order to define the molecular spectrum of mutations in the CFTR gene in Spanish CF patients. Commercial panels showed a limited detection power, leading to the identification of only 76% of alleles. Two scanning techniques, denaturing gradient gel electrophoresis (DGGE) and single strand conformation polymorphism/hetroduplex (SSCP/HD), were carried out to detect CFTR sequence changes. In addition, intragenic markers IVS8CA, IVS8-6(T)n and IVS17bTA were also analyzed. Twelve mutations showed frequencies above 1%, p.F508del being the most frequent mutation (51%). We found that eighteen mutations need to be studied to achieve a detection level of 80%. Fifty-one mutations (42%) were observed once. In total, 121 disease-causing mutations were identified, accounting for 96% (1,877 out of 1,954) of CF alleles. Specific geographic distributions for the most common mutations, p.F508del, p.G542X, c.1811 + 1.6kbA > G and c.1609delCA, were confirmed. Furthermore, two other relatively common mutations (p.V232D and c.2789 + 5G > A) showed uneven geographic distributions. This updated information on the spectrum of CF mutations in Spain will be useful for improving genetic testing, as well as to facilitate counselling in people of Spanish ancestry. In addition, this study contributes to defining the molecular spectrum of CF in Europe, and corroborates the high molecular mutation heterogeneity of Mediterranean populations.

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52 Mutation 0.46-0.35 9 c.1078delT #, p.R347P # 8 p.G85V, c.621 + 1G > T #, p.S549R (T > G) #, p.R553X #, c.3849 + 10kbC > T # 7 p.R347H #, c.1812-1G > A, p.R709X 0.30-0.10 6 p.H199Y, p.P205S, 5 p.R117H #, p.G551D #, p.W1089X, p.Y1092X, CFTR50kbdel 4 c.296 + 3insT, c.1717-1G > A #, c.1949del84, c.3849 + 1G > A 3 p.E92K, c.936delTA, c.1717-8G > A, c.1341G > A, p.A561E, c.2603delT, p.G1244E, [p.D1270N; p.R74W] 2 p.Q2X, p.P5L, CFTRdele2,3, p.S50P, p.E60K, c.405 + 1G > A, c.1677delTA, p.L558S, p.G673X, p.R851X, p.Y1014C, p.Q1100P, p.M1101K, p.D1152H, CFTRdele19, p.G1244V, p.Q1281X, p.Y1381X <0,1 1 c.124del23bp, p.Q30X, p.W57X, c.406-1G > A, p.Q98R, p.E115del, c.519delT, p.L159S, c.711 + 3A > T, p.W202X, c.875 + 1G > A, p.E278del, p.W361R, c.1215delG, p.L365P, p.A399D, c.1548delG, p.K536X, p.R560G, c.1782delA, p.L571S, [p.G576A; p.R668C], p.T582R, p.E585X, c.1898 + 1G > A, c.1898 + 3A > G, c.2051delTT, p.E692X, p.R851L, c.2711delT, c.2751 + 3A > G, c.2752-26A > G, p.D924N, p.S945L, c.3121-1G > A, p.V1008D, p.L1065R, [p.R1070W; p.R668C], [p.F1074L; 5T], p.H1085R, p.R1158X, c.3659delC #, c.3667del4, c.3737delA, c.3860ins31, c.3905insT #, c.4005 + 1G > A, p.T1299I, p.E1308X, p.Q1313X, c.4095 + 2T > A, rearrangements study (n = 4) Mutations identified in CF families with mixed European origin: c.182delT, p.L1254X, c.4010del4. Login to comment
67 Seven other complex alleles were observed: [c.296 + 3insT; p.V754M], [p.F508del; p.I1027T], [p.S549R; -102T > A], [p.G576A; p.R668C], [p.R1070W; p.R668C], [p.D1270N; p.R74W] and [p.T1299I; p.I148T]. Login to comment

[hide] CFTR mutation combinations producing frequent comp... Hum Mutat. 2012 Nov;33(11):1557-65. doi: 10.1002/humu.22129. Epub 2012 Jul 2. El-Seedy A, Girodon E, Norez C, Pajaud J, Pasquet MC, de Becdelievre A, Bienvenu T, des Georges M, Cabet F, Lalau G, Bieth E, Blayau M, Becq F, Kitzis A, Fanen P, Ladeveze V
CFTR mutation combinations producing frequent complex alleles with different clinical and functional outcomes.
Hum Mutat. 2012 Nov;33(11):1557-65. doi: 10.1002/humu.22129. Epub 2012 Jul 2., [PMID:22678879]

Abstract [show]
Genotype-phenotype correlations in cystic fibrosis (CF) may be difficult to establish because of phenotype variability, which is associated with certain CF transmembrane conductance regulator (CFTR) gene mutations and the existence of complex alleles. To elucidate the clinical significance of complex alleles involving p.Gly149Arg, p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys, we performed a collaborative genotype-phenotype correlation study, collected epidemiological data, and investigated structure-function relationships for single and natural complex mutants, p.[Gly576Ala;Arg668Cys], p.[Gly149Arg;Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala;Arg668Cys]. Among 153 patients carrying at least one of these mutations, only three had classical CF and all carried p.Gly149Arg in the triple mutant. Sixty-four had isolated infertility and seven were healthy individuals with a severe mutation in trans, but none had p.Gly149Arg. Functional studies performed on all single and natural complex mutants showed that (1) p.Gly149Arg results in a severe misprocessing defect; (2) p.Asp443Tyr moderately alters CFTR maturation; and (3) p.Gly576Ala, a known splicing mutant, and p.Arg668Cys mildly alter CFTR chloride conductance. Overall, the results consistently show the contribution of p.Gly149Arg to the CF phenotype, and suggest that p.[Arg668Cys], p.[Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala;Arg668Cys] are associated with CFTR-related disorders. The present study emphasizes the importance of comprehensive genotype-phenotype and functional studies in elucidating the impact of mutations on clinical phenotype. Hum Mutat 33:1557-1565, 2012. (c) 2012 Wiley Periodicals, Inc.

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2 To elucidate the clinical significance of complex alleles involving p.Gly149Arg, p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys, we performed a collaborative genotype-phenotype correlation study, collected epidemiological data, and investigated structure-function relationships for single and natural complex mutants, p.[Gly576Ala;Arg668Cys], p.[Gly149Arg; Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala; Arg668Cys]. Login to comment
5 Functional studies performed on all single and natural complex mutants showed that (1) p.Gly149Arg results in a severe misprocessing defect; (2) p.Asp443Tyr moderately alters CFTR maturation; and (3) p.Gly576Ala, a known splicing mutant, and p.Arg668Cys mildly alter CFTR chloride conductance. Login to comment
6 Overall, the results consistently show the contribution of p.Gly149Arg to the CF phenotype, and suggest that p.[Arg668Cys], p.[Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala;Arg668Cys] are associated with CFTR-related disorders. Login to comment
20 Although some variants have been considered neutral because they were identified in the non-CF allele of the parents of CF patients, they seem to be involved in moderate forms or syndromes of late onset, as reported for c.2002C>T, p.Arg668Cys (R668C) and c.1727G>C, p.Gly576Ala (G576A) [Fanen et al., 1992]. Login to comment
24 We thus implemented a collaborative study through the FrenchCFLaboratoryNetworktocollectallpatientsandindividuals carrying p.Asp443Tyr, p.Gly576Ala, p.Arg668Cys, and p.Gly149Arg, either in isolation or in complex alleles, and gathered epidemiological data on these mutations from the general population of France. Login to comment
26 Materials and Methods Patients and Healthy Individuals Patients and healthy individuals known to the French CF Laboratory Network before 1st January 2009, who were heterozygous for the p.Asp443Tyr, p.Gly576Ala, p.Arg668Cys, and p.Gly149Arg mutations, either in isolation or in a complex allele, were included. Login to comment
31 Epidemiological Study in the French General Population The allelic prevalences of the p.Asp443Tyr, p.Gly576Ala, p.Arg668Cys, and p.Gly149Arg mutations, either in isolation or in a complex allele, were determined by allele counting in a sample of healthy adult individuals from the French general population. Login to comment
44 Specific substitutions observed either in isolation (p.Gly149Arg, p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys) or in different combinations in patients were introduced into the WT CFTR plasmid using the Gene tailor site-directed mutagenesis kit (Invitrogen) and the designed primers (available upon request), in accordance with the manufacturer`s protocol (Fig. 1). Login to comment
91 Results Phenotype of Patients Carrying p.Asp443Tyr, p.Gly576Ala, p.Arg668Cys, and/or p.Gly149Arg in Various Combinations A total of 153 patients and healthy individuals carrying at least one of the alleles p.Asp443Tyr, p.Gly576Ala, p.Arg668Cys, and/or p.Gly149Arg, either in isolation or in a complex allele, were identified (Table 1). Login to comment
95 Phenotype and Genotype Data of Patients Carrying At Least One of the CFTR Gene Mutations p.Gly549Arg, p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys Phenotype CFTR genotype No. Login to comment
97 GI, cholestasis 2 m,1 y, 4 y, NA NA p.[Gly576Ala;Arg668Cys] NI 1 CF? Login to comment
98 Bronchitis, ENT 16 y 55, 58 p.[Gly576Ala;Arg668Cys] p.Arg75Glu 1 CF? Login to comment
99 P 59 y 80 p.[Gly576Ala;Arg668Cys] NI 1 CF? Login to comment
101 Failure to thrive 2 y 20-59 p.[Gly576Ala;Arg668Cys] p.Phe508del 1 CF? Login to comment
102 P 1 y 36-48 p.[Gly576Ala;Arg668Cys] p.Phe508del 1 CF? Login to comment
104 [2002C>T;3718-2477C>T] (3849+10kbC>T) p.Glu92Asn 2 DB 60 y, 71 y NA p.[Gly576Ala;Arg668Cys] p.Phe508del 1 DB Pa infections 20 y 67 p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.[Gly576Ala;Arg668Cys] 1 DB 17 y <40 p.[Gly576Ala;Arg668Cys] NI 1 DB 26 y 23-71 p.[Gly576Ala;Arg668Cys] p.Leu997Phe 1 DB Pa infections 72 y 34-60 p.[Gly576Ala;Arg668Cys] NI 1 DB Azoospermia NA NA p.Arg668Cys NI 1 DB 66 y 80-87 p.[Asp443Tyr;Gly576Ala;Arg668Cys] c.262_263delTT (394delTT) 1 CSD ENT 19 y NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Phe508del 1 CSD Bronchitis 48 y NA p.[Gly576Ala;Arg668Cys] p.Phe508del 1 CSD Sinusitis, bronchiolitis 72 y NA p.[Gly576Ala;Arg668Cys] p.Phe508del 1 CSD Nasal polyposis 18 y >60 c. Login to comment
105 [2002C>T;3718-2477C>T] p.Gln689X 2 CSD Nasal polyposis 14 y,16 y NA, 29 p.[Gly576Ala;Arg668Cys] NI 3 IP 35-39 y NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] NI 1 IP Bronchitis 49 y NA p.[Gly576Ala;Arg668Cys] p.PheF508del 1 IP 42 y NA p.[Gly576Ala;Arg668Cys] p.Arg668Cys 1 IP NA NA p.[Gly576Ala;Arg668Cys] c.1210_34TG[12]T[5] 4 IP 19-69 y NA p.[Gly576Ala;Arg668Cys] NI 1 Cholestasis 60 y NA p.[Gly576Ala;Arg668Cys] c.1584G>A 33 CBAVD 27-50 y 9-82 p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Phe508del 2 CBAVD 30 y,36 y NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] c.2051_2052delAAinsG 1 CBAVD 34 y 72 p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Trp1282X 1 CBAVD NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Asn1303Lys 1 CBAVD 35 y 65-66 p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Ser549Asn 1 CBAVD NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] c.3605delA 1 CBAVD 30 y 41-69 p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Gln1411X 1 CBAVD 31 y NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Arg347His 3 CBAVD 29 y, 34 y, NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Gly542X 1 CBAVD 35 y NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] c.946delT 1 CBAVD 26 y NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] c.4242_4242+1delGGinsT 1 CBAVD 41 y 31 p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Arg117His 1 CBAVD 32 y NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Thr338Ile 1 CBAVD NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Glu379Lys 1 CBAVD NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Met1137Val 1 CBAVD NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Thr1246Ile 2 CBAVD NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] NI 1 CBAVD 34 NA p.[Gly576Ala;Arg668Cys] p.Asn1303Lys 8 CBAVD 30-42 y NA p.[Gly576Ala;Arg668Cys] NI 1 CBAVD 27 y NA p.Arg668Cys p.Phe508del 1 CBAVD 30 y NA p.Arg668Cys NI 1 CUAVD NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Phe508del 1 CUAVD NA NA p.[Gly576Ala;Arg668Cys] NI 1 CUAVD Renal agenesis NA NA p.[Gly576Ala;Arg668Cys] NI 1 Hypofertility (not CBAVD) CF carrier`s partner NA NA p.[Gly576Ala;Arg668Cys] p.Asp1152His 1 FBA Mild CF considered possible, 2 older brothers with the same genotype, one with a very mild phenotype, the other being asymptomatic 22 wg NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Asn1303Lys 1 FBA TOP for de novo chromosomal translocation; not CF 21 wg NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Arg31Cys 1 FBA Not CF at birth 28 wg <30 p.[Gly576Ala;Arg668Cys] p.Phe508del 1 FBA Unknown outcome 23 wg NA p.[Gly576Ala;Arg668Cys] p.Phe508del 1 FBA Not CF at birth 21 wg <30 p.[Gly576Ala;Arg668Cys] p.Trp846X (Continued) Table 1. Login to comment
107 of patients Main diagnosis Additional information Age at diagnosis Sweat test (Cl-,mmol/L) Allele 1 Allele 2 1 FBA Fetal death 20 wg NA p.[Gly576Ala;Arg668Cys] p.Ser1235Arg 1 FBA Unknown outcome p.Arg668Cys p.Phe508del 1 FBA Not CF at birth 38 wg NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] NI 1 FBA Not CF at birth 28 wg NA p.[Gly576Ala;Arg668Cys] NI 1 Healthy CF patient`s mother NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] p.Phe508del 1 Healthy Newborn, elevated IRT but normal ST (not CF) Birth <30 p.[Gly576Ala;Arg668Cys] p.Phe508del 1 Healthy Mother of a CF fetus (p.[Phe508del]+ [phe508del]) NA NA p.[Gly576Ala;Arg668Cys] p.Phe508del 1 Healthy Mother of a fetus with FBA but not affected with CF NA NA p.[Gly576Ala;Arg668Cys] p.Phe508del 2 Healthy Mother of a fetus with FBA but not affected with CF NA NA p.[Gly576Ala;Arg668Cys] NI 1 Healthy CF patient`s mother 59 y NA p.[Gly576Ala;Arg668Cys] p.Phe508del 1 Healthy CF patient`s mother NA NA p.[Gly576Ala;Arg668Cys] p.[Ser912Leu;Asn1303Lys] 1 Healthy CF patient`s mother 32 y NA p.[Gly576Ala;Arg668Cys] p.Leu137Arg 1 Healthy CF carrier`s partner NA NA p.[Gly576Ala;Arg668Cys] c. Login to comment
108 [3705T>G;1210-13T[5]] 1 Healthy CF carrier`s partner NA NA p.[Ser519Gly;Gly576Ala;Arg668Cys] NI 2 Healthy CF carrier`s partner 37 y, NA NA p.[Asp443Tyr;Gly576Ala;Arg668Cys] NI 20 Healthy CF carrier`s partner 24-42 y NA p.[Gly576Ala;Arg668Cys] NI 1 Healthy CF carrier`s partner 32 y NA p.Gly576Ala NI 1 Healthy CF patient`s mother 37 y NA p.Arg668Cys p.Arg792X 1 Healthy CF relative (p.Gly745X) 22 y NA p.Arg668Cys NI 1 Healthy General population NA NA p.[Gly576Ala;Arg668Cys] NI CF, cystic fibrosis; CF?, suspicion of cystic fibrosis; CBAVD, congenital bilateral absence of vas deferens; CSD, chronic sinus disease; DB, disseminated bronchiectasis; ENT, ear, nose, and throat symptoms; FBA, fetal bowel anomaly; GI, gastrointestinal symptoms; IP, idiopathic pancreatitis; IRT, immunoreactive trypsinemia; m, months; NA, not available; NI, not identified; P, pulmonary symptoms; Pa: Pseudomonas aeruginosa; PI, pancreatic insufficiency; wg, weeks of gestation; ST, sweat test; TOP, termination of pregnancy; y, years. Login to comment
113 The most frequent phenotype associated with combinations of p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys was CBAVD. Login to comment
120 Of the 37 healthy individuals, seven had a severe CF mutation in trans; one carried the triple mutant p.[Asp443Tyr;Gly576Ala;Arg668Cys]; five carried the double mutant p.[Gly576Ala;Arg668Cys]; and one carried p.Arg668Cys in isolation. Login to comment
121 These observations in patients carrying varied combinations of p.Arg668Cys, p.Gly576Ala, p.Asp443Tyr in trans with a classical CF mutation argue against as considering them as CF defects, but as CFTR-RD-associated mutations. Login to comment
122 Epidemiological Data from the French General Population Of the 1,423 healthy individuals screened, 26 were heterozygous for p.[Gly576Ala;Arg668Cys] (allelic frequency 0.91%, 95% CI 0.60-1.33%); four for p.[Asp443Tyr;Gly576Ala;Arg668Cys] (allelic frequency 0.14%, 95% CI 0.04-0.36%); two for p.Arg668Cys; two for p.Gly576Ala (allelic frequency for each 0.07%, 95% CI 0.0080.25%); and one for p.[Ser519Gly;Gly576Ala;Arg668Cys] (allelic frequency 0.04%, 95% CI 0.0009-0.20%). Login to comment
125 Processing of CFTR Mutants To evaluate the contribution of each mutation to the phenotype, we first studied the maturation of CFTR in HeLa cells that had been transiently transfected with cDNA encoding the WT and mutated CFTR proteins p.Gly149Arg, p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys in different combinations. Login to comment
132 A: Western blot analysis of the CFTR expression: 1, WT; 2, p.Gly576Ala; 3, p.Arg668Cys; 4, p.[Gly576Arg;Arg668Cys]; 5, p.[Asp443Tyr;Gly576Ala;Arg668Cys]; 6, pTracer; 7, p.Asp443Tyr. Login to comment
140 The relative amount of fully glycosylated protein (band C) did not differ between p.Gly576Ala, p.Arg668Cys, or p.[Gly576Ala; Arg668Cys] and WT CFTR. Login to comment
146 As shown in Figure 3, p.Gly576Ala, p.Arg668Cys, p.Asp443Tyr, p.[Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala;Arg668Cys] were targeted to the plasma membrane (Figs. 3B-F). Login to comment
151 Functional Analysis of Chloride Channel Function in CFTR Mutants To determine the impact of p.Gly149Arg, p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys in single, double, or triple mutants on CFTR chloride channel function, we expressed full-length WT and mutant proteins in HeLa cells, and measured chloride channel activity using single-cell fluorescence imaging and the potential-sensitive probe DiSBAC2(3)(Molecular Probes). Login to comment
152 The CFTR Cl- channel conductance was detected at the plasma membrane in WT CFTR and mutants containing p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys, whereas no conductance was observed in cells transfected with either GFP negative control or p.Phe508del protein (Figs. 4A and 4B). Login to comment
155 In contrast, p.Gly576Ala and p.Arg668Cys mutants exhibited a slight but significant reduction of levels of CFTR conductance (P < 0.05) (Fig. 4B). Login to comment
160 Discussion In the present study, we investigated genotype-phenotype correlations and the in vitro consequences of CFTR mutations: four in isolation (i.e., p.Gly149Arg, p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys) and three complex alleles observed in patients or healthy individuals (i.e., p.[Gly576Ala;Arg668Cys], p.[Asp443Tyr;Gly576Ala;Arg668Cys], and the rarer p.[Gly149Arg; Gly576Ala;Arg668Cys]). Login to comment
165 A: Wild-type CFTR; B: p.Gly576Ala; C: p.Arg668Cys; D: p.Asp443Tyr; E: p.[Gly576Ala;Arg668Cys], F: p.[Asp443Tyr;Gly576Ala;Arg668Cys] are targeted at least to the plasma membrane. Login to comment
173 In contrast, genotypes combining mutants other than p.Gly149Arg, namely p.Arg668Cys, p.[Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala;Arg668Cys], in trans with a CF mutation, were not observed in patients with classical CF, although they were observed in patients with moderate phenotypes, in particular CBAVD. Login to comment
175 This observation is also consistent with the results of the functional studies, which demonstrated residual CFTR function, with p.Asp443Tyr having an effect on protein maturation, and p.Gly576Ala and p.Arg668Cys having an effect on Cl- channel activity. Login to comment
177 The epidemiological data provided further evidence that p.[Gly576Ala;Arg668Cys] is a frequent variant in the general population. Login to comment
179 These results have substantial implications for diagnostic and genetic counseling, as they classify p.[Gly149Arg;Gly576Ala;Arg668Cys] or p.Gly149Arg (even if no CF patient was detected with only this mutation) as a CF-causing mutation, and p.Arg668Cys, p.[Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala;Arg668Cys] as CFTR-RD mutations. Login to comment
184 Likewise, it has been documented that p.Gly576Ala causes partial exon 12 skipping [Pagani et al., 2003]. Login to comment
186 [Gly576Ala;Arg668Cys]and 4. Login to comment
190 Statistical significance was set at *** P < 0.001; ** P < 0.01; * P < 0.05; ns, nonsignificant difference (P > 0.05).B-D:Histogramsreportthemeansoftherelativefluorescencecollectedfromseparateexperiments.B:HeLacellstransfectedwithWTCFTRas positive control, p.F508del or GFP as a negative controls, and CFTR mutants as p.Asp443Tyr, p.Gly576Ala, p.Arg668Cys. Login to comment

[hide] Measurements of CFTR-Mediated Cl(-) Secretion in H... PLoS One. 2012;7(10):e47708. doi: 10.1371/journal.pone.0047708. Epub 2012 Oct 17. Sousa M, Servidoni MF, Vinagre AM, Ramalho AS, Bonadia LC, Felicio V, Ribeiro MA, Uliyakina I, Marson FA, Kmit A, Cardoso SR, Ribeiro JD, Bertuzzo CS, Sousa L, Kunzelmann K, Ribeiro AF, Amaral MD
Measurements of CFTR-Mediated Cl(-) Secretion in Human Rectal Biopsies Constitute a Robust Biomarker for Cystic Fibrosis Diagnosis and Prognosis.
PLoS One. 2012;7(10):e47708. doi: 10.1371/journal.pone.0047708. Epub 2012 Oct 17., [PMID:23082198]

Abstract [show]
BACKGROUND: Cystic Fibrosis (CF) is caused by approximately 1,900 mutations in the CF transmembrane conductance regulator (CFTR) gene encoding for a cAMP-regulated chloride (Cl(-)) channel expressed in several epithelia. Clinical features are dominated by respiratory symptoms, but there is variable organ involvement thus causing diagnostic dilemmas, especially for non-classic cases. METHODOLOGY/PRINCIPAL FINDINGS: To further establish measurement of CFTR function as a sensitive and robust biomarker for diagnosis and prognosis of CF, we herein assessed cholinergic and cAMP-CFTR-mediated Cl(-) secretion in 524 freshly excised rectal biopsies from 118 individuals, including patients with confirmed CF clinical diagnosis (n = 51), individuals with clinical CF suspicion (n = 49) and age-matched non-CF controls (n = 18). Conclusive measurements were obtained for 96% of cases. Patients with "Classic CF", presenting earlier onset of symptoms, pancreatic insufficiency, severe lung disease and low Shwachman-Kulczycki scores were found to lack CFTR-mediated Cl(-) secretion (<5%). Individuals with milder CF disease presented residual CFTR-mediated Cl(-) secretion (10-57%) and non-CF controls show CFTR-mediated Cl(-) secretion >/=30-35% and data evidenced good correlations with various clinical parameters. Finally, comparison of these values with those in "CF suspicion" individuals allowed to confirm CF in 16/49 individuals (33%) and exclude it in 28/49 (57%). Statistical discriminant analyses showed that colonic measurements of CFTR-mediated Cl(-) secretion are the best discriminator among Classic/Non-Classic CF and non-CF groups. CONCLUSIONS/SIGNIFICANCE: Determination of CFTR-mediated Cl(-) secretion in rectal biopsies is demonstrated here to be a sensitive, reproducible and robust predictive biomarker for the diagnosis and prognosis of CF. The method also has very high potential for (pre-)clinical trials of CFTR-modulator therapies.

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103 As to the 5 individuals showing inconclusive Ussing chamber measurements, one individual had one CF-disease causing mutation (G542X) and two individuals had RD- related mutations (V562I and G576A). Login to comment

[hide] Genotype-phenotype correlation in cystic fibrosis ... Genet Mol Biol. 2011 Jul;34(3):416-20. Epub 2011 Jul 1. Polizzi A, Tesse R, Santostasi T, Diana A, Manca A, Logrillo VP, Cazzato MD, Pantaleo MG, Armenio L
Genotype-phenotype correlation in cystic fibrosis patients bearing [H939R;H949L] allele.
Genet Mol Biol. 2011 Jul;34(3):416-20. Epub 2011 Jul 1., [PMID:21931512]

Abstract [show]
Cystic fibrosis (CF) is caused by CFTR (cystic fibrosis transmembrane conductance regulator) gene mutations. We ascertained five patients with a novel complex CFTR allele, with two mutations, H939R and H949L, inherited in cis in the same exon of CFTR gene, and one different mutation per patient inherited in trans in a wide population of 289 Caucasian CF subjects from South Italy. The genotype-phenotype relationship in patients bearing this complex allele was investigated. The two associated mutations were related to classical severe CF phenotypes.

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76 The R668C in exon 13 is considered a polymorphism (Pignatti et al., 1994) while the G576A, in CFTR exon 12, seems to induce a variable extent of exon skipping that leads to reduced levels of normal CFTR transcripts (Pagani et al., 2003). Login to comment

[hide] Prenatal and newborn screening for CFTR mutations:... Clin Biochem. 2011 May;44(7):485-6. Schwarz MJ
Prenatal and newborn screening for CFTR mutations: the difficulties of prediction.
Clin Biochem. 2011 May;44(7):485-6., [PMID:22036338]

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18 An example of the former is the variant G576A (p.Gly576Ala) which, when in trans with a typically severe CF-causingmutation suchas F508del, can give rise to Congenital Bilateral Absence of the Vasa Deferentia (CBAVD) or disseminated bronchiectasis-two distinct symptoms of cystic fibrosis. Login to comment

[hide] The K+ channel opener 1-EBIO potentiates residual ... PLoS One. 2011;6(8):e24445. Epub 2011 Aug 31. Roth EK, Hirtz S, Duerr J, Wenning D, Eichler I, Seydewitz HH, Amaral MD, Mall MA
The K+ channel opener 1-EBIO potentiates residual function of mutant CFTR in rectal biopsies from cystic fibrosis patients.
PLoS One. 2011;6(8):e24445. Epub 2011 Aug 31., [PMID:21909392]

Abstract [show]
BACKGROUND: The identification of strategies to improve mutant CFTR function remains a key priority in the development of new treatments for cystic fibrosis (CF). Previous studies demonstrated that the K(+) channel opener 1-ethyl-2-benzimidazolone (1-EBIO) potentiates CFTR-mediated Cl(-) secretion in cultured cells and mouse colon. However, the effects of 1-EBIO on wild-type and mutant CFTR function in native human colonic tissues remain unknown. METHODS: We studied the effects of 1-EBIO on CFTR-mediated Cl(-) secretion in rectal biopsies from 47 CF patients carrying a wide spectrum of CFTR mutations and 57 age-matched controls. Rectal tissues were mounted in perfused micro-Ussing chambers and the effects of 1-EBIO were compared in control tissues, CF tissues expressing residual CFTR function and CF tissues with no detectable Cl(-) secretion. RESULTS: Studies in control tissues demonstrate that 1-EBIO activated CFTR-mediated Cl(-) secretion in the absence of cAMP-mediated stimulation and potentiated cAMP-induced Cl(-) secretion by 39.2+/-6.7% (P<0.001) via activation of basolateral Ca(2)(+)-activated and clotrimazole-sensitive KCNN4 K(+) channels. In CF specimens, 1-EBIO potentiated cAMP-induced Cl(-) secretion in tissues with residual CFTR function by 44.4+/-11.5% (P<0.001), but had no effect on tissues lacking CFTR-mediated Cl(-) conductance. CONCLUSIONS: We conclude that 1-EBIO potentiates Cl(-)secretion in native CF tissues expressing CFTR mutants with residual Cl(-) channel function by activation of basolateral KCNN4 K(+) channels that increase the driving force for luminal Cl(-) exit. This mechanism may augment effects of CFTR correctors and potentiators that increase the number and/or activity of mutant CFTR channels at the cell surface and suggests KCNN4 as a therapeutic target for CF.

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46 CFabsent CFresidual CFTR genotype Number of individuals CFTR genotype Number of individuals F508del/F508del 10 F508del/Y161C 1 F508del/W57X 1 F508del/V232D 1 F508del/G85E 3 F508del/R334W 2 F508del/120del23 1 F508del/T338I 1 F508del/182delT 1 F508del/I1234V 1 F508del/G542X 1 F508del/3272-26 A.G 1 F508del/A561E 1 F508del/3849+10 kb C.T 1 F508del/Y1092X 1 F508del/4005 +5727 A.G 1 F508del/N1303K 1 F508del/G576A 1 F508del/1525-1 G.A 2 N1303K/R334W 1 F508del/Q39X 1 F1052V/M1137R 1 F508del/Q552X 1 1898+3 A.G/ 1898+3 A.G 1 G85E/G85E 1 R334W/3199del6 1 Q552X/R1162X 1 R334W/X 1 A561E/A561E 2 dele2,3/X 1 R764X/1717-1 G.A 1 R1158X/2183AA.G 1 R1158X/R560T 1 doi:10.1371/journal.pone.0024445.t001 luminal and basolateral surfaces of the epithelium were perfused continuously with a solution of the following composition (mmol/ L): NaCl 145, KH2PO4 0.4, K2HPO4 1.6, D-glucose 5, MgCl2 1, Ca-gluconate 1.3, pH 7.4, at 37uC. Login to comment

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

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

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51 Sequences of the Primers Used for CFTR Analysis by HRM, GC Size, Amplicon Length, Number of Positive Controls Validated for Each Exon, and Positive Controls for Routine Analysis Exon Primer Sequences GC length Amplicon length (bp) Introns Number of heterozygous- positive controls Number of homozygous- positive controls Recommended control 1 LSCFE1Fmod 5Ј-CCGCCGCCGTTGAGCGGCAGGCACC-3Ј 8 200 bp 74 4 125GϾC LSCFE1Rmod 5Ј-CCGCCGCCGGCACGTGTCTTT CCGAAGCT-3Ј 8 19 M1I 2 2i5b 5Ј-CAAATCTGTATGGAGACC-3Ј 0 194 bp 39 5 R31C 2i3Љ 5Ј-CAACTAAACAATGTACATGAAC-3Ј 0 4 296ϩ1GϾT 3 LSCFe3Fmod LSCFe3Rmod 5Ј-CGCCGTTAAGGGAAATAGGACAA CTAAAATA-3Ј 5 276 bp 44 10 2 R75Q 5Ј-CCGCCGATTCACCAGATTTCGTAGTC-3Ј 6 66 G85V 4 LSCFe4FmodC 5Ј-CCGCCGCCGCCCGTGTTGAAATT CTCAGGGT-3Ј 12 361 bp 52 14 1 R117H LSCFe4RmodC 5Ј-CCGCCGCCCACATGTACGATAC AGAATATATGTGCC-3Ј 9 26 574delA 5 LSCFE5Fmod 5Ј-CCGCCGGTTGAAATTATCTAACTTTCC-3Ј 6 201 bp 13 8 624delT LSCFE5Rmod 5Ј-CCGAACTCCGCCTTTCCAGTTGT-3Ј 3 48 711ϩ1GϾT 6a LSCF6aFmod2 5Ј-CCGCCGGGGTGGAAGAT ACAATGACACCTG-3Ј 5 317 bp 25 8 C225X LSCF6aRmod2 5Ј-CCGCCGCCGCGATGCATAGAG CAGTCCTGGTT-3Ј 11 66 L206W 6b LSCFE6bFmod 5Ј-CGCGCCGCCGGATTTAC AGAGATCAGAGAG-3Ј 10 239 bp 0 2 1 R258G LSCFE6Brmod 5Ј-CCGCCGCCGAGGTGGA GTCTACCATGA-3Ј 8 66 1001ϩ11CϾT 7 LSCFE7Fmod2 5Ј-CCGCCGCCCTCTCCCTGAATTT TATTGTTATTGTTT-3Ј 13 326 bp 7 11 1078delT LSCFE7Rmod2 5Ј-CCCGCCGCCCTATAATGCAG CATTATGGT-3Ј 10 7 1248ϩ1GϾT 8 LSCFE8Fmod 5Ј-CCGGAATGCATTAATGCTAT TCTGATTC-3Ј 4 199 bp 32 7 W401X LSCFE8Rmod 5Ј-CCCGCAGTTAGGTGTTTAG AGCAAACAA-3Ј 4 18 1249-5AϾG 9 LSCFe9Fmod2 5Ј-CCGCCGCCGGGAATTATTTGAGAA AGCAAAACA-3Ј 8 279 bp 0 3 D443Y LSCFe9Rmod2 5Ј-CCGCCGCGAAAATACCTTCCAG CACTACAAACTAGAAA-3Ј 8 57 A455E 10 LSCF10FmodD 5Ј-CGCCGTTATGGGAGAACTGG AGCCTTCAGAG-3Ј 5 275 bp 0 15 1 F508del LSCF10RmodD 5Ј-CCGCAGACTAACCGATTGAAT ATGGAGCC-3Ј 4 68 E528E 11 h11i5 5Ј-TGCCTTTCAAATTCAGATTGAGC-3Ј 0 197 bp 42 13 2 G542X 11i3ter 5Ј-ACAGCAAATGCTTGCTAGACC-3Ј 0 17 G551D 12 LSCFE12Fmod 5Ј-CGCGTCATCTACACTAGATGACCAG-3Ј 4 244 bp 43 15 G576A 1898 ϩ 1GϾALSCFE12Rmod 5Ј-CCGGAGGTAAAATGCAATCTATGATG-3Ј 3 63 13 LSCF13AFmod 5Ј-CCGCCGCCGGAGACATATTG CAATAAAGTAT-3Ј 9 38 20 I601F LSCF13ARmod 5Ј-GCCTGTCCAGGAGACAGGA GCATCTC-3Ј 2 R668C LSCF13BFmod 5Ј-CCGCCGCAATCCTAACTGAG ACCTTACACCG-3Ј 2 R668C LSCF13BRmod 5Ј-CCGCCGATCAGGTTCAGGA CAGACTGC-3Ј 3 346 bp 2184insA LSCF13CFmod 5Ј-CCGCGGTGATCAGCACTGGCCC-3Ј 6 301 bp 77 L749L LSCF13CRmod 5Ј-CCGCGCGCGCGGCCAGTTTCTTG AGATAACCTTCT-3Ј 13 259 bp V754M LSCF13DFmod 5Ј-CGTGTCACTGGCCCCTCAGGC-3Ј 1 221 bp I807M LSCF13DRmof 5Ј-CCGCCGCCGCTAATCCTATGA TTTTAGTAAAT-3Ј 9 220 bp 2622ϩ1GϾA LSCf13FFmod 5Ј-CGCGGTGCAGAAAGAAGAAAT TCAATCCTAACTG-3Ј 4 R668C LSCF13FRmod 5Ј-CCGCCGTGCCATTCATTTGT AAGGGAGTCT-3Ј 6 2184insA 14a LSCF14aFmodB 5Ј-CCGACCACAATGGTGGCAT GAAACTG-3Ј 3 239 bp 35 7 1 T854T LSCF14aRmodB 5Ј-CCGCCGACTTTAAATCCAGTAAT ACTTTACAATAGAACA-3Ј 6 7 W846X 14b LSCF14bFmod 5Ј-CCGGAGGAATAGGTGAAGAT-3Ј 2 179 bp 38 4 2752-5GϾT LSCF14bRmodb 5Ј-CCGTACATACAAACATAGTGGATT-3Ј 3 59 2789ϩ5GϾT 15 LSCFE15Fmod 5Ј-CGCGCCGTGTATTGGAAA TTCAGTAAGTAACTTTGG-3Ј 7 412 bp 33 16 T908S LSCFE15Rmod 5Ј-CCGCAGCCAGCACTGCCAT TAGAAA-3Ј 4 68 S945L (table continues) phisms that we have chosen to exclude. Login to comment
171 Results of CFTR Analysis by HRM on 136 Samples of Patients with Idiopathic Chronic Pancreatitis (ICP) Exon Number of positive samples Mutations identified Variants identified New positive controls 1 14 14 125GϾC 2 1 1 R31C 3 9 1 G85E 7 R75Q 1 R74W 4 4 1 R117G 1 I148T R117G 1 R117H 1 A120T 5 1 1 L188P L188P 6a 5 1 V201M 1 A221A A221A 3 875ϩ40 AϾG 6b 27 1 M284T 26 1001ϩ11CϾT M284T 7 1 1 L320V L320V 8 0 0 9 1 1 D443Y 10 16 8 F508del 8 E528E 11 1 1 G542X 12 6 4 G576A 1 Y577Y L568F 1 L568F 13 7 1 S737F 4 R668C S737F 1 V754M L644L 1 L644L 14a 53 52 T854T T854TϩI853I 1 T854TϩI853I 14b 0 0 15 3 1 L967S T908S 1 T908S 1 S945L 16 0 0 17a 10 7 L997F 1 3271ϩ18CϾT 3271 ϩ 3AϾG 1 3271 ϩ 3 AϾG 1 Y1014C 17b 3 1 L1096L L1096L 1 H1054DϩG1069R 1 3272-33AϾG H1054DϩG1069R 3272-33AϾG 18 2 1 D1152H E1124del 1 E1124del 19 5 5 S1235R poly 20 7 1 W1282X 5 P1290P 1 D1270N 21 2 1 N1303K 1 T1299T 22 0 0 23 1 0 4374ϩ13 AϾG 24 43 40 Q1463Q 2 Y1424Y 1 Q1463QϩY1024Y ing domain of a gene brings an excellent sensitivity for heterozygote detection that is very close to 100%. Login to comment

[hide] Diagnostic testing by CFTR gene mutation analysis ... J Mol Diagn. 2005 May;7(2):289-99. Schrijver I, Ramalingam S, Sankaran R, Swanson S, Dunlop CL, Keiles S, Moss RB, Oehlert J, Gardner P, Wassman ER, Kammesheidt A
Diagnostic testing by CFTR gene mutation analysis in a large group of Hispanics: novel mutations and assessment of a population-specific mutation spectrum.
J Mol Diagn. 2005 May;7(2):289-99., [PMID:15858154]

Abstract [show]
Characterization of CFTR mutations in the U.S. Hispanic population is vital to early diagnosis, genetic counseling, patient-specific treatment, and the understanding of cystic fibrosis (CF) pathogenesis. The mutation spectrum in Hispanics, however, remains poorly defined. A group of 257 self-identified Hispanics with clinical manifestations consistent with CF were studied by temporal temperature gradient electrophoresis and/or DNA sequencing. A total of 183 mutations were identified, including 14 different amino acid-changing novel variants. A significant proportion (78/85) of the different mutations identified would not have been detected by the ACMG/ACOG-recommended 25-mutation screening panel. Over one third of the mutations (27/85) occurred with a relative frequency >1%, which illustrates that the identified mutations are not all rare. This is supported by a comparison with other large CFTR studies. These results underscore the disparity in mutation identification between Caucasians and Hispanics and show utility for comprehensive diagnostic CFTR mutation analysis in this population.

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98 Spectrum of CFTR Sequence Variants in 257 Hispanic Patients Who Underwent Diagnostic DNA Testing for CF Mutations in 257 patients Allele counts of each mutation % of variant alleles (183) % of all alleles tested (514) ACMG/ACOG recommended 25 mutation panel* DeltaF508 53 28.96 10.31 G542X 7 3.83 1.36 R334W 2 1.09 0.39 R553X 2 1.09 0.39 DeltaI507 1 0.55 0.19 1717 - 1 GϾA 1 0.55 0.19 3120 ϩ 1 GϾA 1 0.55 0.19 7 different mutations 67 36.61 13.04 All mutations included ACMG/ACOG 1248 ϩ 1 GϾA 1 0.55 0.19 1249 - 29delAT 1 0.55 0.19 1288insTA1288insTA 1 0.55 0.19 1341 ϩ 80 GϾA1341 ϩ 80 GϾA 1 0.55 0.19 1429del71429del7 1 0.55 0.19 1525 - 42 GϾA1525 - 42 GϾA 1 0.55 0.19 1717 - 1 GϾA 1 0.55 0.19 1717 - 8 GϾA 2 1.09 0.39 1811 ϩ 1 GϾA1811 ϩ 1 GϾA 1 0.55 0.19 2055del9-ϾA 3 1.64 0.58 2105-2117del13insAGAAA 1 0.55 0.19 2215insG 1 0.55 0.19 2585delT2585delT 1 0.55 0.19 2752 - 6 TϾC 1 0.55 0.19 296 ϩ 28 AϾG 1 0.55 0.19 3120 ϩ 1 GϾ A 1 0.55 0.19 3271 ϩ 8 AϾG3271 ϩ 8 AϾG 1 0.55 0.19 3271delGG 1 0.55 0.19 3272 - 26 AϾG 2 1.09 0.39 3876delA 2 1.09 0.39 4016insT 1 0.55 0.19 406 - 1 GϾA 6 3.28 1.17 406 - 6 TϾC 1 0.55 0.19 4374 ϩ 13 A ϾG 1 0.55 0.19 663delT 1 0.55 0.19 874insTACA874insTACA 1 0.55 0.19 A1009T 2 1.09 0.39 A559T 1 0.55 0.19 D1152H 1 0.55 0.19 D1270N 3 1.64 0.58 D1445N 2 1.09 0.39 D836Y 1 0.55 0.19 DeltaF311 1 0.55 0.19 DeltaF508 53 28.96 10.31 DeltaI507 1 0.55 0.19 E116K 2 1.09 0.39 E585X 1 0.55 0.19 E588VE588V 2 1.09 0.39 E831X 1 0.55 0.19 F311L 1 0.55 0.19 F693L 1 0.55 0.19 G1244E 1 0.55 0.19 G542X 7 3.83 1.36 G576A 1 0.55 0.19 H199Y 3 1.64 0.58 I1027T 3 1.64 0.58 I285FI285F 1 0.55 0.19 L206W 3 1.64 0.58 L320V 1 0.55 0.19 L967S 1 0.55 0.19 L997F 3 1.64 0.58 P1372LP1372L 1 0.55 0.19 P205S 1 0.55 0.19 P439SP439S 1 0.55 0.19 Q1313X 1 0.55 0.19 Q890X 2 1.09 0.39 Q98R 1 0.55 0.19 R1066C 1 0.55 0.19 R1066H 1 0.55 0.19 (Table continues) missense variant, I1027T (3212TϾC), in exon 17a.25 Family studies have not been performed to identify which allele carries two mutations. Login to comment
165 Due to ascertainment bias, six mutations not included in the recommended panel occurred with a relative frequency greater than 1%: E60X, G576A, I1027T, P67L, R668C, and S1235R. Login to comment

[hide] CFTR Cl- channel function in native human colon co... Gastroenterology. 2004 Oct;127(4):1085-95. Hirtz S, Gonska T, Seydewitz HH, Thomas J, Greiner P, Kuehr J, Brandis M, Eichler I, Rocha H, Lopes AI, Barreto C, Ramalho A, Amaral MD, Kunzelmann K, Mall M
CFTR Cl- channel function in native human colon correlates with the genotype and phenotype in cystic fibrosis.
Gastroenterology. 2004 Oct;127(4):1085-95., [PMID:15480987]

Abstract [show]
BACKGROUND & AIMS: Cystic fibrosis (CF) is caused by over 1000 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and presents with a widely variable phenotype. Genotype-phenotype studies identified CFTR mutations that were associated with pancreatic sufficiency (PS). Residual Cl- channel function was shown for selected PS mutations in heterologous cells. However, the functional consequences of most CFTR mutations in native epithelia are not well established. METHODS: To elucidate the relationships between epithelial CFTR function, CFTR genotype, and patient phenotype, we measured cyclic adenosine monophosphate (cAMP)-mediated Cl- secretion in rectal biopsy specimens from 45 CF patients who had at least 1 non-DeltaF508 mutation carrying a wide spectrum of CFTR mutations. We compared CFTR genotypes and clinical manifestations of CF patients who expressed residual CFTR-mediated Cl- secretion with patients in whom Cl- secretion was absent. RESULTS: Residual anion secretion was detected in 40% of CF patients, and was associated with later disease onset (P < 0.0001), higher frequency of PS (P < 0.0001), and less severe lung disease (P < 0.05). Clinical outcomes correlated with the magnitude of residual CFTR activity, which was in the range of approximately 12%-54% of controls. CONCLUSIONS: Specific CFTR mutations confer residual CFTR function to rectal epithelia, which is related closely to a mild disease phenotype. Quantification of rectal CFTR-mediated Cl- secretion may be a sensitive test to predict the prognosis of CF disease and identify CF patients who would benefit from therapeutic strategies that would increase residual CFTR activity.

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78 Relationship Between the CFTR Genotype and Cl- Channel Function in Native Rectal Epithelia CFTR genotype Number of individuals Sweat Cl-concentration (mmol/L)a cAMP-mediated response Carbachol-induced plateau response or maximal lumen-negative response Isc-cAMP (␮A/cm2) Cl- secretion (% of control) Isc-carbachol (␮A/cm2) Cl- secretion (% of control) Cl- secretion absent R1162X/Q552X 1 71 17.1 0 0.7 0 W1282X/3121-2AϾG 1 112 1.9 0 0.6 0 1898 ϩ 1G Ͼ T/1609delCA 2b 114, 118 25.4, 13.4 0, 0 0, 0.7 0, 0 ⌬F508/Q39X 2b 127, 129 2.6, 4.4 0, 0 1.7, 3.7 0, 0 ⌬F508/G542X 1 102 29.0 0 6.6 0 ⌬F508/R553X 3 112, 102, 109 13.1, 4.5, 23.8 0, 0, 0 1.5, 4.4, 1.0 0, 0, 0 ⌬F508/E585X 1 115 1.4 0 1.1 0 ⌬F508/Q637X 1 100 2.9 0 1.2 0 ⌬F508/Y1092X 1 119 0.0 0 -0.3 0 ⌬F508/120del23c 1 72 20.1 0 3.3 0 ⌬F508/182delT 1 116 10.8 0 5.2 0 ⌬F508/3905insT 2 88, 96 8.4, 5.6 0, 0 2.3, -1.1 0, 1 ⌬F508/V520F 1 68 1.2 0 1.7 0 ⌬F508/A561E 3 113, 146, 100 17.0, 17.0, 16.0 0, 0, 0 2.1, 1.5, 3.7 0, 0, 0 ⌬F508/R1066C 1 138 0.0 0 0.0 0 ⌬F508/N1303K 3 100, 117, 94 1.7, 4.1, 1.5 0, 0, 0 -0.6, 2.2, 0.8 0, 0, 0 A561E/A561E 2 101, 116 6.6, 2.0 0, 0 7.3, 3.3 0, 0 Residual Cl- secretiond G542X/I148N 1 75 -50.1 54 -22.2 12 1898 ϩ 3A Ͼ G/1898 ϩ 3A Ͼ G 1 82 -36.8 39 -12.9 7 ⌬F508/3272-26A Ͼ G 1 116 -17.8 19 -27.2 14 ⌬F508/S108F 1 118 -15.8 17 -12.3 7 ⌬F508/R117H 1 90 -35.9 38 -207.7 109 ⌬F508/Y161Cc 1 44 -35.1 37 -45.9 25 ⌬F508/P205S 1 80 -23.3 25 -10.4 5 ⌬F508/V232D 1 120 -16.9 18 -26.9 14 ⌬F508/R334W 1 92 -22.1 23 -21.1 11 ⌬F508/R334W 1 101 -24.5 26 -37.4 20 ⌬F508/T338I 1 73 -44.4 47 -79.4 42 ⌬F508/G576A 1 40 -16.9 18 -115.5 61 ⌬F508/I1234V 1 113 -13.6 15 -8.6 5 G576A/G85E 1 95 -26.1 28 -61.6 32 F1052V/M1137R 1 47 -36.7 39 -146.6 77 M1101K/M1101K 1 94 -11.1 12 -4.8 3 S1159F/S1159F 1 67 -47.9 51 -38.7 21 N1303K/R334W 1 91 -30.3 32 -47.7 25 NOTE. CFTR Cl- channel function was determined in rectal epithelia from Cl- secretory responses induced by IBMX/forskolin (Isc-cAMP) and after co-activation with carbachol (Isc-carbachol). Login to comment
101 Functional Classification and Protein Location of CFTR Mutations Mutation type Severe mutations (protein location) Mild mutations (protein location) Missense V520F, A561E (NBD1) G85E (MSD1, TM1) R1066C (MSD2, CL4) S108F, R117H (MSD1, EL1) N1303K (NBD2) I148N, Y161Ca (MSD1, CL1) P205S (MSD1, TM3) V232D (MSD1, TM4) R334W, T338I (MSD1, TM6) G576A (NBD1) I1234V (NBD2) F1052V, M1101K (MSD2, CL4) M1137R (MSD2, TM12) S1159F (pre-NBD2) Splice 1898 ϩ 1G Ͼ T (R domain) 1898 ϩ 3A Ͼ G (R domain) 3121-2A Ͼ G (MSD2, TM9) 3272-26A Ͼ G (MSD2, TM10) Single amino acid deletion ⌬F508 (NBD1) Nonsense Q39X (N-terminus) G542X, Q552X, R553X, E585X (NBD1) Q637X (R domain) Y1092X (MSD2, CL4) R1162X (pre-NBD2) W1282X (NBD2) Frameshift 120del23a 182delT (N-terminus) 1609delCA (NBD1) 3905insT (NBD2) NOTE. Severe mutation, Cl- secretion absent; mild mutation, residual cAMP-mediated Cl- secretion. Login to comment
123 Residual function also was observed for mutants, which are expected to form membrane Cl- channels that are reduced in number, either owing to improper protein maturation (P205S, M1137R) or owing to reduced levels of full-length CFTR messenger RNA (3272-26AϾG, G576A).32,38 - 40 The only exception was M1101K, which was reported as a loss of function mutation in heterologous cells34 and was associated with residual CFTR function in the 1 homozygous patient studied (Table 1). Login to comment

[hide] Quantitative methods for the analysis of CFTR tran... J Cyst Fibros. 2004 Aug;3 Suppl 2:17-23. Amaral MD, Clarke LA, Ramalho AS, Beck S, Broackes-Carter F, Rowntree R, Mouchel N, Williams SH, Harris A, Tzetis M, Steiner B, Sanz J, Gallati S, Nissim-Rafinifa M, Kerem B, Hefferon T, Cutting GR, Goina E, Pagani F
Quantitative methods for the analysis of CFTR transcripts/splicing variants.
J Cyst Fibros. 2004 Aug;3 Suppl 2:17-23., [PMID:15463919]

Abstract [show]
In cystic fibrosis (CF), transcript analysis and quantification are important for diagnosis, prognosis and also as surrogate markers for some therapies including gene therapy. Classical RNA-based methods require significant expression levels in target samples for appropriate analysis, thus PCR-based methods are evolving towards reliable quantification. Various protocols for the quantitative analysis of CFTR transcripts (including those resulting from splicing variants) are described and discussed here.

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164 D565G, G576A and Y577Y induce exon skipping, while Y577F increases the percentage of exon 12 inclusion. Login to comment
169 In particular, two missense mutations, D565G and G576A (previously considered a neutral polymorphism), showed no clear association with loss of protein function or disease phenotype. Login to comment
173 D565G and G576A induce variable levels of exon 12 skipping, thus reducing levels of normal transcripts. Login to comment

[hide] Cystic fibrosis transmembrane conductance regulato... J Hepatol. 2002 Aug;37(2):192-7. Girodon E, Sternberg D, Chazouilleres O, Cazeneuve C, Huot D, Calmus Y, Poupon R, Goossens M, Housset C
Cystic fibrosis transmembrane conductance regulator (CFTR) gene defects in patients with primary sclerosing cholangitis.
J Hepatol. 2002 Aug;37(2):192-7., [PMID:12127423]

Abstract [show]
BACKGROUND/AIMS: Because biliary tract lesions that resemble those of primary sclerosing cholangitis (PSC) may occur in cystic fibrosis (CF), we examined the prevalence and influence of CF transmembrane conductance regulator (CFTR) gene mutations in PSC patients. METHODS: Genomic DNA was analyzed in 29 consecutive PSC patients and in 115 healthy control individuals. A scanning method followed by direct DNA sequencing was used to scan the CFTR coding regions. RESULTS: Four patients (13.8%) were heterozygous for a CFTR mutation, including a new putative severe CF-causing mutation (N782K), and three mild defects (L997F, D1270N, and S1235R). The comparison of PSC patients with healthy controls showed no significant difference in the frequency of CFTR mutations (P=0.415). In addition, two patients (6.9%) were heterozygous for the IVS8-5T allele, which is not significantly different from the 5-6%-prevalence in the general population. Unusual clinical features including a severe outcome in childhood, with a lethal outcome at age 22, and biliary aspergillosis were recorded in patients with a CFTR mutation. CONCLUSIONS: The proportion of CF carriers is not significantly higher in PSC patients than in the general population. The possibility that CFTR mutations may contribute to a severe clinical course in PSC patients is worth further examining.

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78 Four additional subjects (3.5%) carried one of the following mild defects: R117H, R347H, R74W-D1270N and R668C-G576A. 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
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
113 Eleven mutations were reported as ''complex alleles,`` particularly in chromosomes carrying the 5T allele, although several changes (G576A, R668C, A1067T) are considered as neutral polymorphisms (CFGAC). Login to comment

[hide] Missense mutations in the cystic fibrosis gene in ... Hum Mutat. 1999;14(6):510-9. Lazaro C, de Cid R, Sunyer J, Soriano J, Gimenez J, Alvarez M, Casals T, Anto JM, Estivill X
Missense mutations in the cystic fibrosis gene in adult patients with asthma.
Hum Mutat. 1999;14(6):510-9., [PMID:10571949]

Abstract [show]
Asthma is a complex genetic disorder that affects 5% of adults and 10% of children worldwide. The complete characterization of the cystic fibrosis transmembrane conductance regulator (CFTR) gene identified missense mutations in 15% of 144 unrelated adult patients with asthma, but in none of 41 subjects from the general population. The four more common mutations were analyzed in an extended sample consisting of 184 individuals from the general population and did not show a significant difference in frequency. The hyperfunctional CFTR M470 allele was detected in 90% of patients with CFTR missense mutations, but in 63% of subjects from the general population and 63% of asthma patients without CFTR mutations. None of the patients with missense mutations had the 5T allele of intron 8 of CFTR, responsible for low CFTR levels, while it was detected in 8% of asthma patients without CFTR mutations and in 9% of subjects from the general population. These findings suggest a putative role for a combination of CFTR missense mutations, including the M470 allele, in the genetic variability of asthma.

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61 Missense mutations R75Q, G576A, and L997F were analyzed in the extended sample of individuals from the general population by conventional restriction analysis; mutation R668C was analyzed by SSCA. Login to comment
73 Among the six subjects with two CFTR mutations (Table 1), three presented mutations R668C and G576A. Login to comment
75 However, some studies have detected that mutations R668C and G576A are associated on the same chromosome [Dörk et al., 1997] and it is likely that they correspond to the same CFTR allele. Login to comment
77 Overall, four of the 15 missense mutations (R75Q, G576A, R668C, and L997F) were detected in 57% of the 21 asthma patients. Login to comment
79 With the exception of mutation L997F (2.1% in asthma patients), which was not found in control group 2, the other three mutations were found in these samples with the following frequencies: R75Q (1.6% general population individuals vs. 2.8% asthma patients); G576A (2.7% general population individuals vs. 2.1% asthma patients) and R668C (4.3% general population individuals vs. 3.5% asthma patients). Login to comment
84 Characteristics of Asthmatic Patients With CFTR Mutations CFTR Age IgE Skin Patients genotype1 M470V2 PolyT3 Sex Years BHR4 IU/ml5 test6 SB221 R74W,V8551 M/V 7/7 M 67 - 329 + SB36 R75Q / - M/V 7/7 F 61 + 59 + SB47 R75Q / - M/V 7/9 M 67 NA 42 NA SB131 R75Q / - M/V 7/7 F 69 + 41 - SB296 R75Q / - M/V 7/9 F 45 + 96 - SB251 I148T / - M/V 7/9 F 70 - 25 - SB212 A534Q / - M/M 7/7 F 46 + 69 + SB125 R668C,G576A N/V 7/7 M 62 + 21 - SB154 R668C,G576A M/V 7/7 M 65 + 93 + SB231 R668C,G576A M/V 7/7 F 45 + 158 + SB112 R668C / - M/V 7/7 M 64 + 1350 + SB304 R668C,T582R M/V 7/7 F 78 - 7 - SB56 T896I / - M/V 7/7 M 72 + 77 - SB117 L997F / - V/V 7/9 F 81 NA 6 NA SB143 L997F/L997F V/V 7/7 F 39 NA 129 NA SB173 L997F / - M/V 7/9 F 67 + 127 - SB148 M1028R / - M/V 7/7 F 48 + 23 - SB32 R1066C / - M/V 7/7 F 69 - 9 - SB69 T1142I / - M/M 7/9 M 65 - 158 + SB92 R116L / - M/V 7/7 M 78 NA 64 NA SB53 T1220I / - M/M 7/9 F 60 + 62 + SB40 ∆F508 / - M/M 79 F 62 + 34 + SB9 - / - M/M 5/9 F 61 - 169 - SB20 - / - M/V 5/5 F 57 - 245 + SB116 - / - V/V 5/7 F 33 NA 41 NA SB118 - / - M/V 5/9 M 83 + 63 - SB140 - / - V/V 5/7 F 72 NA 35 NA SB142 - / - M/V 5/7 F 59 + 108 + SB201 - / - M/V 5/7 M 27 - 297 + SB205 - / - M/V 5/7 F 56 - 20 - SB284 - / - M/V 5/7 F 71 - 40 NA SB316 - / - M/V 5/7 F 78 NA 20 - 1 The CFTR genotype was studied by DGGE/SSCP analysis of all CFTR exons and intronic flanking sequences. Login to comment
93 Characteristics of 15 Amino Acid Variants/Mutants in the CFTR Gene Detected in 21 Patients With Asthma Other Evolutive Conservative Other mutations Mutation1 Reference2 Exon Domain3 Patients4 phenotypes5 conservation6 change7 at same position R74W Claustres et al., 1993 3 IC1 1 CF-PS/CBAVD b, m, r, s NC - R75Q Zielenski et al., 1991 3 IC2 4 CF-PS/DB/CBAVD/ b, d, m, r, s, x NC R75X (CF) CF Parents R75L (CBAVD) I148T Bozon et al., 1994 4 IC2 1 CF-PS b, d, m, r, s, x NC I148N (CF) A534Q This report 11 NBF1 1 - b, m NC A534E (CF) G576A Fanen et al., 1992 12 NBF1 3 CF-PS/CBAVD b, m, r, s NC G576X (CF) T582R Casals et al., 1997 12 NBF1 1 CF-PS b, d, m, r, s, x NC T582I (CF) R668C Fanen et al., 1992 13 R 5 DB/CF-PS/CBAVD/ b, d, m, r, s, x NC - CF Parents V855I This report 14a IC6 1 - b, r, s C - T896I This report 15 EC4 1 - b, d, m, r, s NC - L997F Fanen et al., 1992 17a TM9 3 DB/CF-PS/CBAVD/ b, d, m, r, s, x C - non-CF M1028R This report 17a TM10 1 - d NC M1028I (CF) T2066C Fanen et al., 1992 17b IC8 1 DB/CF-PI b, d, m, r, s, x NC R1066S (CF) R1066L (CF) R1066H (CF/CBAVD) T1142I This report 18 TM12 1 - b, d, m, r, s, x NC - R1162L Fanen et al., 1992 19 IC9 1 non-CF b, d, m, r, s, x NC R1162X (CF) T1220I Ghanem et al., 1994 19 NBF2 1 DB/non-CF b, d NC - 1 Mutation name according to the Cystic Fibrosis Genetic Analysis Consortium. Login to comment

[hide] Spectrum of CFTR mutations in the Middle North of ... Hum Mutat. 1999;14(1):89. Telleria JJ, Alonso MJ, Calvo C, Alonso M, Blanco A
Spectrum of CFTR mutations in the Middle North of Spain and identification of a novel mutation (1341G-->A). Mutation in brief no. 252. Online.
Hum Mutat. 1999;14(1):89., [PMID:10447267]

Abstract [show]
We have analyzed 39 unrelated cystic fibrosis (CF) families by denaturing gradient gel electrophoresis (DGGE) and direct sequencing in order to determine the spectrum of CF mutations in our population. This approach has allowed us to detect 72 out of the 78 CF chromosomes (92.3%). The DF508 mutation was found to be present in 51/78 (65.4%) CF chromosomes, in accordance with the predicted Northwest-Southeast gradient within the European population. Another 14 known mutations, and the novel 1341G-->A mutation were identified. Nine out of fifteen non DF508 mutations were present in a single chromosome. The 1341G-->A mutation, found in 2 unrelated patients, is a new mutation associated to severe phenotype, causing pancreatic insufficiency and chronic lung infections. Our data suggest a different distribution of non-DF508 mutations in our population when compared with previous studies carried out in Spanish CF families. Six out of the 14 non-F508 in our study were not present in a recent study carried out in 640 Spanish families with CE These six mutations account for 29.6% non DF508 chromosomes in our sample.

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33 Spectrum of CFTR Mutations Table 1 Spectrum of CFTR mutations identified in the present study compared with data published by Casals et al. (Casals et al. 1997) This study Casals et al. Mutation Exon/Intron n % n % ∆F508 E 10 51 65.4 681 53.2 711+1G→T I 5 3 3.8 22 1.7 G542X E 11 3 3.8 108 8.43 1213delT E 7 2 2.6 0 0 1341G→A E 8 2 2.6 0 0 R1066C E 17b 2 2.6 14 1.09 1717-1G→A I 10 1 1.3 1 0.08 S549R E 11 1 1.3 0 0 V562I E 12 1 1.3 0 0 G576A E 12 1 1.3 0 0 2183AA→G E13 1 1.3 5 0.39 2789+5G→A I 14b 1 1.3 11 0.86 Q890X E 15 1 1.3 13 1.01 3849+1G→A I 19 1 1.3 0 0 N1303K E 21 1 1.3 34 2.65 Other 0 0 391 30.5 Known mutations 72 92.3 1155 90.23 Unknown mutations 6 7.7 125 9.7 DISCUSSION The knowledge of the spectrum of mutations causing CF in any specific geographic region provide useful information to design the best approach in pre and postnatal diagnosis of CF; for the screening of mutations in the population at risk; to stimate the genetic risk etc. Moreover, the response to different therapeutic approaches could vary depending on the CF mutations in any case. 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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91 R. Knowles, Q1352H by T. Nukiwa and K. Seyama are indicated g Missense substitutions R933S and R75Q occurred together in a ∆F508 heterozygous patient h Q1352H is associated with 5T and R297W, respectively i Missense substiutions G576A and R668C are linked on the same allele in both CBAVD patients sence of the vas deferens (CUAVD) and one heterozygote with CBAVD. Login to comment
113 The membrane topology of the CFTR protein was adapted from the original report and has been confirmed in vitro by glycosylation site mutagenesis (Riordan et al. 1989; Chang et al. 1994) double mutant allele G576A and R668C, have previously been reported to be benign but no other mutation could be detected on these alleles in our patients after scanning the whole coding region, except for one case where the R75Q and R933S mutations were found together in a ∆F508 heterozygote. Login to comment
130 The missense substitutions G576A and R668C occurred in cis on the same allele in two of our CBAVD males and in three further patients with very mild CF (data not shown); it is thus difficult to decide whether one or both of these changes are required to predispose towards mild disease (Anguiano et al. 1992; Fanen et al. 1992; Chillón et al. 1995). 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
188 The two linked missense substitutions G576A and R668C, for example, have previously been classified as polymorphisms on normal chromosomes (Fanen et al. 1992), as polymorphisms on CBAVD alleles (Osborne et al. 1993; Culard et al. 1994) or as separate disease-causing mutations in CBAVD (Anguiano et al. 1992; Chillón et al. 1995; Mercier et al. 1995). 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] Increased incidence of cystic fibrosis gene mutati... Hum Mol Genet. 1995 Apr;4(4):635-9. Pignatti PF, Bombieri C, Marigo C, Benetazzo M, Luisetti M
Increased incidence of cystic fibrosis gene mutations in adults with disseminated bronchiectasis.
Hum Mol Genet. 1995 Apr;4(4):635-9., [PMID:7543317]

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

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5 Moreover, three rare CFTR gene DNA polymorphisms (G576A, R668C, and 2736 A-*G), not deemed to be the cause of CF, were found in two patients, one of which was a compound heterozygote with R1066C. Login to comment
53 Clinical data and CFTR genotypes of patients with bronchiectasis CFTR genotype sex (yr) age age of onset smoke FEV1 FVC sweat mM 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 A F508/U U/U R1066C/2736A->G R75Q/U MI137V/U U/U U/U U/U U/U 3667 ins 4/U U/U U/U G576A-R668C/L997F U/U U/U U/U F F F M F F M M M F M F F M M F 52 70 23 79 55 52 57 42 43 52 21 66 38 59 49 70 3 56 20 50 18 16 16 8 2 6 5 8 20 8 10 42 no no no yes no no no no no no no no ex ex no no 40 80 85 n.d. 54 49 n.d. 59 83 40 91 62 105 36 49 55 45 88 83 n.d. 54 59 n.d. 59 93 47 105 77 99 46 64 64 40 19 6 70 45 28 n.d. 54 n.d. neg 30 neg 58 neg 20 28 # = patient number; FEV1 = forced expiratory volume in I second (% of predicted value); FVC = forced vital capacity (% of predicted value); sweat = sweat test (sodium concentration); U = unknown mutation or no mutation; ex = ex smoker; neg = negative test, no value recorded (cut off value = 80 mM Na); n.d. = not done. Login to comment
62 Polymorphisms G576A (1859G->C) and R668C (2134C->T) have been detected in patient #13. Login to comment
63 G576A and R668C are syntenic, as determined by segregation analysis in her two children. Login to comment
64 G576A and R668C were first described as DNA polymorphisms in CF chromosomes (20). Login to comment
65 G576A was found only in this patient. Login to comment

[hide] Identification of three novel mutations in the CFT... Hum Genet. 1994 Aug;94(2):154-8. Grade K, Grunewald I, Graupner I, Behrens F, Coutelle C
Identification of three novel mutations in the CFTR gene using temperature-optimized non-radioactive conditions for SSCP analysis.
Hum Genet. 1994 Aug;94(2):154-8., [PMID:7519167]

Abstract [show]
Optimal temperature conditions for the detection of 28 known mutations on 15 exons of the human cystic fibrosis transmembrane conductance regulator gene by single strand conformation polymorphism analysis using the Diagen TGGE Apparatus were established. This procedure was applied to the detection of unknown mutations in 58 non-deltaF508 chromosomes. Three novel mutations, -471del3 (5' flanking region), 3171insC (exon 17a) and 4700(T)8/9 (3' non-translated region) of the CFTR gene were found. Mutation 3171insC occurred in conjunction with the delta F508 mutation on the other allele of a child presenting with severe pathology. Mutation -471del3 has so far only been found in one healthy individual and her father, and 4700(T)8/9 is a DNA sequence polymorphism.

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24 G542X G551D R553X G576A Splice rout. 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] Molecular characterization of cystic fibrosis: 16 ... Genomics. 1992 Jul;13(3):770-6. Fanen P, Ghanem N, Vidaud M, Besmond C, Martin J, Costes B, Plassa F, Goossens M
Molecular characterization of cystic fibrosis: 16 novel mutations identified by analysis of the whole cystic fibrosis conductance transmembrane regulator (CFTR) coding regions and splice site junctions.
Genomics. 1992 Jul;13(3):770-6., [PMID:1379210]

Abstract [show]
The spectrum of cystic fibrosis (CF) mutations was determined in 105 patients by using denaturing gradient gel electrophoresis to screen the entire coding regions and adjacent cystic fibrosis transmembrane conductance regulator (CFTR) gene sequences. The nucleotide substitutions detected included 16 novel mutations, 11 previously described defects, and 11 nucleotide sequence polymorphisms. Among the novel mutations, 6 were of the missense type, 4 were nonsense mutations, 4 were frameshift defects, and 2 affected mRNA splicing. The mutations involved all the CFTR domains, including the R domain. Of the 61 non-delta F508 CF chromosomes studied, mutations were found on 36 (59%), raising the proportion of CF alleles characterized in our patient cohort to 88%. Given the efficacy of the screening method used, the remaining uncharacterized mutations probably lie in DNA sequences outside the regions studied, e.g., upstream-promoter sequences, the large introns, or putative regulatory regions. Our results further document the highly heterogeneous nature of CF mutations and provide the information required for DNA-based genetic testing.

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101 Similarly, other substitutions of the G-C (or A-T) type were detected, e.g., the D44V (Fig. l), K710X, and G576A substitutions (Tables 2 and 3). Login to comment

[hide] CFTR gene mutations and asthma in the Norwegian En... Respir Med. 2006 Dec;100(12):2121-8. Epub 2006 May 5. Munthe-Kaas MC, Lodrup Carlsen KC, Carlsen KH, Skinningsrud B, Haland G, Devulapalli CS, Pettersen M, Eiklid K
CFTR gene mutations and asthma in the Norwegian Environment and Childhood Asthma study.
Respir Med. 2006 Dec;100(12):2121-8. Epub 2006 May 5., [PMID:16678395]

Abstract [show]
BACKGROUND: Several candidate genes have been implicated in the etiology of asthma, including the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). Mutations in the CFTR gene result in derangements of mucociliary clearance. Homozygotes for CFTR mutations develop cystic fibrosis (CF), a disorder characterized mainly by lung and pancreas disease. OBJECTIVE: To investigate whether there was an increased frequency of CFTR mutations in asthma patients. METHODS: Seven hundred and three subjects aged 10-11 years from the environment and childhood asthma (ECA) study were included in the present study. Possible associations between asthma, reduced lung function, bronchial hyperresponsiveness (BHR), and increased or decreased nitrogen oxide (NO) levels (based on structural parental interview, spirometry, PD20 methacholine challenge test and exhaled NO measurements), and the five most common CFTR mutations in Norway (DeltaF508, R117H, R117C, 4005+2T-->C, 394delTT), the modulating polymorphisms IVS8(TG)mTn and the IVS8-5T were investigated. RESULTS: No association were found between asthma, reduced lung function, BHR or exhaled NO levels and CF heterozygosity. However, the IVS8(TG)11T7 haplotype was associated with normal lung function. CONCLUSIONS: Our results do not support the hypothesis that CFTR mutations or polymorphisms play a role in the pathogenesis of asthma in children. However, the distribution of Tn(TG)m haplotypes differed between individuals with reduced lung function and individuals with normal lung function.

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25 CFTR mutation Alleles (%) F508del 184 (62.2) R117C 12 (4.1) R117H 12 394delTT 11 (3.8) 4005+2T-C 11 G551D 6 (2.0) 3659delC 5 (1.7) E60X 4 (1.4) V232D 4 1525-2A-G 3 (1.0) N1303K 3 G542X 2 (0.7) E279X 2 R75X 2 S912X 2 E116X 1 (0.3) L295Q 1 R347L 1 Q493X 1 I506L 1 I507del 1 R553X 1 G576A 1 621-1G-T 1 2183AA-G 1 S945L 1 R1162X 1 I1234V 1 3849+10 kbC-T 1 W1282X 1 Unknown 18 (6.5) Total alleles 296 (100%) Mutations detected with OLA31 m kit-74%. Login to comment

[hide] Symmetric snapback primers for scanning and genoty... Clin Chem. 2013 Jul;59(7):1052-61. doi: 10.1373/clinchem.2013.202689. Epub 2013 Mar 15. Zhou L, Palais RA, Ye F, Chen J, Montgomery JL, Wittwer CT
Symmetric snapback primers for scanning and genotyping of the cystic fibrosis transmembrane conductance regulator gene.
Clin Chem. 2013 Jul;59(7):1052-61. doi: 10.1373/clinchem.2013.202689. Epub 2013 Mar 15., [PMID:23503723]

Abstract [show]
BACKGROUND: High-resolution melting of PCR products is an efficient and analytically sensitive method to scan for sequence variation, but detected variants must still be identified. Snapback primer genotyping uses a 5' primer tail complementary to its own extension product to genotype the resulting hairpin via melting. If the 2 methods were combined to analyze the same PCR product, the residual sequencing burden could be reduced or even eliminated. METHODS: The 27 exons and neighboring splice sites of the CFTR [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)] gene were amplified by the PCR in 39 fragments. Primers included snapback tails for genotyping 7 common variants and the 23 CFTR mutations recommended for screening by the American College of Medical Genetics. After symmetric PCR, the amplicons were analyzed by high-resolution melting to scan for variants. Then, a 5-fold excess of H2O was added to each reaction to produce intramolecular hairpins for snapback genotyping by melting. Each melting step required <10 min. Of the 133 DNA samples analyzed, 51 were from CFTR patient samples or cell lines. RESULTS: As expected, the analytical sensitivity of heterozygote detection in blinded studies was 100%. Snapback genotyping reduced the need for sequencing from 7.9% to 0.5% of PCR products; only 1 amplicon every 5 patients required sequencing to identify nonanticipated rare variants. We identified 2 previously unreported variants: c.3945A>G and c.4243-5C>T. CONCLUSIONS: CFTR analysis by sequential scanning and genotyping with snapback primers is a good match for targeted clinical genetics, for which high analytical accuracy and rapid turnaround times are important.

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134 For example, by directing snapback primers to genotype an additional 2 synonymous variants (p.Y1424Y and p.T966T) and a syntenic pair of variants (p.G576A and p.R668C) that constitute a complex allele (26, 27), the sequencing required for the patients we have analyzed could be reduced by an additional factor of 2 (see Table 5 in the online Data Supplement). Login to comment

[hide] Effect of ivacaftor on CFTR forms with missense mu... J Cyst Fibros. 2014 Jan;13(1):29-36. doi: 10.1016/j.jcf.2013.06.008. Epub 2013 Jul 23. Van Goor F, Yu H, Burton B, Hoffman BJ
Effect of ivacaftor on CFTR forms with missense mutations associated with defects in protein processing or function.
J Cyst Fibros. 2014 Jan;13(1):29-36. doi: 10.1016/j.jcf.2013.06.008. Epub 2013 Jul 23., [PMID:23891399]

Abstract [show]
BACKGROUND: Ivacaftor (KALYDECO, VX-770) is a CFTR potentiator that increased CFTR channel activity and improved lung function in patients age 6 years and older with CF who have the G551D-CFTR gating mutation. The aim of this in vitro study was to evaluate the effect of ivacaftor on mutant CFTR protein forms with defects in protein processing and/or channel function. METHODS: The effect of ivacaftor on CFTR function was tested in electrophysiological studies using a panel of Fischer rat thyroid (FRT) cells expressing 54 missense CFTR mutations that cause defects in the amount or function of CFTR at the cell surface. RESULTS: Ivacaftor potentiated multiple mutant CFTR protein forms that produce functional CFTR at the cell surface. These included mutant CFTR forms with mild defects in CFTR processing or mild defects in CFTR channel conductance. CONCLUSIONS: These in vitro data indicated that ivacaftor is a broad acting CFTR potentiator and could be used to help stratify patients with CF who have different CFTR genotypes for studies investigating the potential clinical benefit of ivacaftor.

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116 Other examples of complex CFTR alleles include the number of TG repeats in intron 8 along with the 5T CFTR mutation (e.g., TG11-5T, TG12-5T, TG13-5T), R668C-G576A-D443Y, and R74W-D1270N [8,16]. Login to comment

[hide] ATP and AMP mutually influence their interaction w... J Biol Chem. 2013 Sep 20;288(38):27692-701. doi: 10.1074/jbc.M113.479675. Epub 2013 Aug 6. Randak CO, Dong Q, Ver Heul AR, Elcock AH, Welsh MJ
ATP and AMP mutually influence their interaction with the ATP-binding cassette (ABC) adenylate kinase cystic fibrosis transmembrane conductance regulator (CFTR) at separate binding sites.
J Biol Chem. 2013 Sep 20;288(38):27692-701. doi: 10.1074/jbc.M113.479675. Epub 2013 Aug 6., [PMID:23921386]

Abstract [show]
Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel in the ATP-binding cassette (ABC) transporter protein family. In the presence of ATP and physiologically relevant concentrations of AMP, CFTR exhibits adenylate kinase activity (ATP + AMP &lrarr2; 2 ADP). Previous studies suggested that the interaction of nucleotide triphosphate with CFTR at ATP-binding site 2 is required for this activity. Two other ABC proteins, Rad50 and a structural maintenance of chromosome protein, also have adenylate kinase activity. All three ABC adenylate kinases bind and hydrolyze ATP in the absence of other nucleotides. However, little is known about how an ABC adenylate kinase interacts with ATP and AMP when both are present. Based on data from non-ABC adenylate kinases, we hypothesized that ATP and AMP mutually influence their interaction with CFTR at separate binding sites. We further hypothesized that only one of the two CFTR ATP-binding sites is involved in the adenylate kinase reaction. We found that 8-azidoadenosine 5'-triphosphate (8-N3-ATP) and 8-azidoadenosine 5'-monophosphate (8-N3-AMP) photolabeled separate sites in CFTR. Labeling of the AMP-binding site with 8-N3-AMP required the presence of ATP. Conversely, AMP enhanced photolabeling with 8-N3-ATP at ATP-binding site 2. The adenylate kinase active center probe P(1),P(5)-di(adenosine-5') pentaphosphate interacted simultaneously with an AMP-binding site and ATP-binding site 2. These results show that ATP and AMP interact with separate binding sites but mutually influence their interaction with the ABC adenylate kinase CFTR. They further indicate that the active center of the adenylate kinase comprises ATP-binding site 2.

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322 Mutations G576A, G550R, and Q1352H have been described in patients with congenital bilateral absence of the vas deferens, a condition that affects men with cystic fibrosis but can also occur in the absence Nucleotide Interactions with the ABC Adenylate Kinase CFTR SEPTEMBER 20, 2013ߦVOLUME 288ߦNUMBER 38 JOURNAL OF BIOLOGICAL CHEMISTRY 27699 of other disease manifestations. Login to comment

[hide] Defining the disease liability of variants in the ... Nat Genet. 2013 Oct;45(10):1160-7. doi: 10.1038/ng.2745. Epub 2013 Aug 25. Sosnay PR, Siklosi KR, Van Goor F, Kaniecki K, Yu H, Sharma N, Ramalho AS, Amaral MD, Dorfman R, Zielenski J, Masica DL, Karchin R, Millen L, Thomas PJ, Patrinos GP, Corey M, Lewis MH, Rommens JM, Castellani C, Penland CM, Cutting GR
Defining the disease liability of variants in the cystic fibrosis transmembrane conductance regulator gene.
Nat Genet. 2013 Oct;45(10):1160-7. doi: 10.1038/ng.2745. Epub 2013 Aug 25., [PMID:23974870]

Abstract [show]
Allelic heterogeneity in disease-causing genes presents a substantial challenge to the translation of genomic variation into clinical practice. Few of the almost 2,000 variants in the cystic fibrosis transmembrane conductance regulator gene CFTR have empirical evidence that they cause cystic fibrosis. To address this gap, we collected both genotype and phenotype data for 39,696 individuals with cystic fibrosis in registries and clinics in North America and Europe. In these individuals, 159 CFTR variants had an allele frequency of l0.01%. These variants were evaluated for both clinical severity and functional consequence, with 127 (80%) meeting both clinical and functional criteria consistent with disease. Assessment of disease penetrance in 2,188 fathers of individuals with cystic fibrosis enabled assignment of 12 of the remaining 32 variants as neutral, whereas the other 20 variants remained of indeterminate effect. This study illustrates that sourcing data directly from well-phenotyped subjects can address the gap in our ability to interpret clinically relevant genomic variation.

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175 cIn the 1000 Genomes Project, this variant is always seen in cis with p.Gly576Ala; in this study, it is seen both in cis and on its own. Login to comment

[hide] CFTR mutations spectrum and the efficiency of mole... PLoS One. 2014 Feb 26;9(2):e89094. doi: 10.1371/journal.pone.0089094. eCollection 2014. Zietkiewicz E, Rutkiewicz E, Pogorzelski A, Klimek B, Voelkel K, Witt M
CFTR mutations spectrum and the efficiency of molecular diagnostics in Polish cystic fibrosis patients.
PLoS One. 2014 Feb 26;9(2):e89094. doi: 10.1371/journal.pone.0089094. eCollection 2014., [PMID:24586523]

Abstract [show]
Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane regulator gene (CFTR). In light of the strong allelic heterogeneity and regional specificity of the mutation spectrum, the strategy of molecular diagnostics and counseling in CF requires genetic tests to reflect the frequency profile characteristic for a given population. The goal of the study was to provide an updated comprehensive estimation of the distribution of CFTR mutations in Polish CF patients and to assess the effectiveness of INNOLiPA_CFTR tests in Polish population. The analyzed cohort consisted of 738 patients with the clinically confirmed CF diagnosis, prescreened for molecular defects using INNOLiPA_CFTR panels from Innogenetics. A combined efficiency of INNOLiPA CFTR_19 and CFTR_17_TnUpdate tests was 75.5%; both mutations were detected in 68.2%, and one mutation in 14.8% of the affected individuals. The group composed of all the patients with only one or with no mutation detected (109 and 126 individuals, respectively) was analyzed further using a mutation screening approach, i.e. SSCP/HD (single strand conformational polymorphism/heteroduplex) analysis of PCR products followed by sequencing of the coding sequence. As a result, 53 more mutations were found in 97 patients. The overall efficiency of the CF allele detection was 82.5% (7.0% increase compared to INNOLiPA tests alone). The distribution of the most frequent mutations in Poland was assessed. Most of the mutations repetitively found in Polish patients had been previously described in other European populations. The most frequent mutated allele, F508del, represented 54.5% of Polish CF chromosomes. Another eight mutations had frequencies over 1%, 24 had frequencies between 1 and 0.1%; c.2052-2053insA and c.3468+2_3468+3insT were the most frequent non-INNOLiPA mutations. Mutation distribution described herein is also relevant to the Polish diaspora. Our study also demonstrates that the reported efficiency of mutation detection strongly depends on the diagnostic experience of referring health centers.

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53 Another substitution, G576A (SVM +1.73), was found in three patients, in cis with a deleterious R668C allele (SVM -1.61); the latter was also present without G576A, in two patients (in one with c.1585-1G.A in trans). Login to comment
54 In the UMD-CFTR database (www.umd.be/CFTR), G576A and R668C have been reported in cis; in the CFTR2 database both mutations are described as having ''varying consequences``. Login to comment
55 Three of our patients carrying R668C were PI, and two appeared PS; PS/PI status was independent on the presence of G576A. Login to comment
56 We considered R668C a pathogenic mutation, and G576A - an associated element of a compound allele. Login to comment
71 Exon / intron (legacy) Exon / intron (Ensembl) Protein change SVM value cDNA (HGVS nomenclature) gDNA (cDNA +132 bp) Number of PL CF chromosomes Reference a Mutations in trans Pathogenic mutations 1 1 L15Ffs10X c.43delC 175delC 1 CFMDB 1717-1G.A 2 2 G27V 21.92 c.80G.T 212G.T 1 Novel F508del 2 2 S18RfsX16 c.54-5940_273 +10250del21kb exon2,3del21kb 66 IL19 various CF mutations i2 i2 IVS2_Donor c.164+1G.A 296+1G.A 3 CFMDB various CF mutations 3 3 G85E 22.61 c.254G.A 386G.A 1 IL17 unknown 3 3 E60X c.178G.T 310G.T 0 IL17 x 3 3 L88IfsX22 c.262_263delTT 394delTT 0 IL17 x 4 4 E92K 21.92 c.274G.A 406G.A 2 CFMDB c.164+1G.A; c.2051- 2AA.G 4 4 L101X c.302T.G 434T.G 1 CFMDB c.3717+12191C.T 4 4 K114IfsX5 c.341_353del13bp 473del13bp 1 Novel F508del 4 4 R117H 20.35 c.350G.A 482G.A 5 IL17 F508del; 2x unknown 4 4 R117C 22.07 c.349C.T 481C.T 2 CFMDB S1206X;1x unknown 4 4 L137_L138insT c.412_413insACT L138ins 1 CFMDB F508del 4 4 R153I 22.61 c.458G.T 590G.T 2 Novel F508del; c.3527delC i4 i4 IVS4_Donor c.489+1G.T 621+1G.T 5 IL17 F508del; c.489+1G.T 5 5 L165X c.494T.A 626T.A 1 Novel F508del i5 i5 IVS5_Donor c.579+1G.T 711+1G.T 0 IL19 x i5 i5 IVS5_Donor c.579+3A.G 711+3A.G 2 CFMDB 2,3del21kb; c.2052-3insA i5 i5 IVS5_Donor c.579+5G.A 711+5G.A 0 IL17 x 7 8 F311L 20.90 c.933C.G 965C.G 2 CFMDB 2x F508 7 8 G314R 20.58 c.940G.A 1072G.A 4 CFMDB various CF mutations 7 8 F316LfsX12 c.948delT 1078delT 1 IL17 unkown 7 8 R334W 22.41 c.1000C.T 1132C.T 6 IL17 various CF mutations 7 8 I336K 22.07 c.1007T.A 1139T.A 2 CFMDB 2,3de21kb; F508del 7 8 R347P 22.27 c.1040G.C 1172G.C 11 IL17 various CF mutations i7 i8 IVS8_Donor c.1116+2T.A 1248+2T.A 1 Novel Q1412X 9 10 A455E 22.61 c.1364C.A 1496C.A 0 IL17 x i9 i10 IVS10_Donor c.1392+1G.A 1524+1G.A 1 CFMDB c.3816-7delGT 10 11 S466X c.1397C.G 1529C.G 1 CFMDB G542X 10 11 I507del c.1519_1521delATC 1651delATC 2 IL19 F508del 10 11 F508del c.1521_1523delCTT 1654delCTT 805 IL19 various CF mutations i10 i11 IVS11_Acceptor c.1585-1G.A 1717-1G.A 27 IL19 various CF mutations 11 12 G542X c.1624G.T 1756G.T 25 IL19 various CF mutations 11 12 G551D 21.24 c.1624G.T 1756G.T 5 IL19 various CF mutations 11 12 Q552X c.1654C.T 1786C.T 0 IL19 x 11 12 R553X c.1657C.T 1789C.T 14 IL19 various CF mutations 11 12 R560T 21.92 c.1679G.C 1811G.C 0 IL19 x i12 i13 IVS13_Donor c.1766+1G.A 1898+1G.A 6 IL19 various CF mutations i12 i13 IVS13_Donor c.1766+1G.C 1898+1G.C 1 CFMDB F508del 13 14 H620P 21.73 c.1859A.C 1991A.C 1 CFMDB F508del 13 14 R668C//G576A 21.61//1.73 c.2002C.T//c.1727G.C 2134C.T// 1859G.C 5 b CFMDB// rs1800098 c.1585-1G.A; 4 unknown 13 14 L671X c.2012delT 2143delT 27 IL17 various CF mutations 13 14 K684SfsX38 c.2051_2052delAAinsG 2183AA.G 10 IL17 various CF mutations 13 14 K684NfsX38 c.2052delA 2184delA 0 IL17 x 13 14 Q685TfsX4 c.2052_2053insA 2184insA 15 CFMDB various CF mutationsc , 1 unknown Table 2. Cont. Exon / intron (legacy) Exon / intron (Ensembl) Protein change SVM value cDNA (HGVS nomenclature) gDNA (cDNA +132 bp) Number of PL CF chromosomes Reference a Mutations in trans 13 14 L732X c.2195T.G 2327T.G 1 CFMDB F508del 14A 15 R851X c.2551C.T 2683C.T 3 CFMDB various CF mutations 14A 15 I864SfsX28 c.2589_2599del11bp 2721del11bp 2 CFMDB F508del; 2,3del21kb i14B i16 IVS16_Donor c.2657+2_2657+3insA 2789+2insA 1 CFMDB F508del i14B i16 IVS16_Donor c.2657+5G.A 2789+5G.A 0 IL17 unkown 15 17 Y919C 21.02 c.2756A.G 2888A.G 1 CFMDB unknown 15 17 H939HfsX27 c.2817_2820delTACTC 2949delTACTC 1 Novel unkown i15 i17 IVS17_Donor c.2908+3A.C 3040+3A.C 1 Novel F508del i16 i18 IVS18_Donor c.2988+1G.A 3120+1G.A 0 IL19 x 17A 19 I1023_V1024del c.3067_3072delATAGTG 3199del6 0 IL19 x i17A i19 IVS19 c.3140-26A.G 3272-26A.G 9 IL19 various CF mutations 17B 20 L1065R 21.90 c.3194T.G 3326T.G 1 CFMDB F508del 17B 20 Y1092X c.3276C.A 3408C.A 1 CFMDB R334W i18 i21 IVS21_Donor c.3468+2_3468+3insT 3600+2insT 11 CFMDB various CF mutationsd , 1 unknown 18 21 E1126EfsX7 c.3376_3379delGAAG 3508delGAAG 1 Novel F508del 19 22 R1158X c.3472C.T 3604C.T 2 CFMDB F508del; R553X 19 22 R1162X c.3484C.T 3616C.T 1 IL17 F508del 19 22 L1177SfsX15 c.3528delC 3659delC 4 IL17 various CF mutations 19 22 S1206X c.3617C.A 3749C.A 1 CFMDB R117C i19 i22 IVS22 c.3717+12191C.T 3849+10kbC.T 58 IL17 various CF mutations 20 23 G1244R 22.62 c.3730G.C 3862G.C 1 CFMDB F508del 20 23 S1251N 22.28 c.3752G.A 3884G.A 0 IL19 x 20 23 L1258FfsX7 c.3773_3774insT 3905insT 0 IL19 x 20 23 V1272VfsX28 c.3816_3817delGT 3944delGT 1 CFMDB c.1392+1G.A 20 23 W1282X c.3846G.A 3978G.A 9 IL19 various CF mutations 21 24 N1303K 22.62 c.3909C.G 4041C.G 18 IL19 various CF mutations 22 25 V1327X c.3979delG 4111delG 1 Novel F508del 22 25 S1347PfsX13 c.4035_4038dupCCTA c.4167dupCCTA 1 CFMDB 2,3del21kb 23 26 Q1382X c.4144C.T 4276C.T 1 CFMDB F508del 23 26 Q1412X c.4234C.T 4366C.T 2 CFMDB F508del; c.1116+2T.A i23 i26 IVS26_Donor c.4242+1G.T 4374+1G.T 1 CFMDB F508del Sequence changes of uncertain pathogenic effect, tentatively counted as mutations 6A 6 E217G 0.30 c.650A.G 782A.G 1 CFMDB; rs1219109046 unknown 7 8 R352Q 20.01 c.1055G.A 1187G.A 1 CFMDB; rs121908753 F508del 7 8 Q359R 0.33 c.1076A.G 1208A.G 1 CFMDB F508del i8 i9 IVS9 c.1210-12T5_1210- 34_35 (TG)12 1332-12Tn_- 34TGm 6 CFMDB F508del; 3x unknown i8 i9 IVS9 c.1210-12T5_1210- 34_35 (TG)13 1332-12Tn_- 34TGm 2 CFMDB 2143delT; 1x unknown i8 i9 IVS9 c.1210-12T8 1332-12Tn 1 Novel unknown 10 11 I506V 20.21 c.1516A.G 1648A.G 1 CFMDB; rs1800091 unknown 12 13 V562L 0.79 c.1684G.C 1816G.C 1 CFMDB; rs1800097 unknown 13 14 G723V 0.44 c.2168G.T 2300G.T 1 CFMDB; rs200531709 unknown 15 17 D924N 0.03 c.2770G.A 2902G.A 1 CFMDB; rs201759207 unknown patient with F508del on another allele) was not supported by the SVM value (+0.35); the patient was PS and had ambiguous chloride values (45, 64 and 83 mmol/L). 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101 The more recent estimates provide much lower values, ranging from 1:5000 [14], 1:6000 cited in WHO 2002 report [15] to 1:7500 for Southeastern Poland estimated for a 1-year period of Table 2. Cont. Exon / intron (legacy) Exon / intron (Ensembl) Protein change SVM value cDNA (HGVS nomenclature) gDNA (cDNA +132 bp) Number of PL CF chromosomes Reference a Mutations in trans 15 17 L967S 0.27 c.2900T.C 3032T.C 1 CFMDB; rs1800110 unknown 18 21 D1152H 0.50 c.3454G.C 3586G.C 1 CFMDB; rs75541969 F508del Sequence changes considered as lacking pathogenic effect 4 4 I148T 2.04 c.443T.U 575T.U 4 IL19e unknown 13 14 I752V 0.35 c.2254A.G 2386A.G 1 Novelf F508 15 17 S912L 2.12 c.2735C.T 2867C.T 1 CFMDBg ; rs121909034 F508 Legend: a IL19 i 17 - mutations included in the INNOLiPA tests (see below); CFMDB - non-INNOLiPA mutations present in the CTFR mutation database; novel - mutations first reported in this study; b in three chromosomes R668C with G576A in trans; c F508del, c.1585-1G.A, G542X, N1303K or c.579+3A.G; d F508del, G542X, R553X or N1303K; e not pathogenic if not in cis with c.3067-72del6 (l.n.3199del6); f not pathogenic - see explanation the text; g not pathogenic if not in cis with G1244V. 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] Biosynthesis of cystic fibrosis transmembrane cond... Int J Biochem Cell Biol. 2014 Jul;52:26-38. doi: 10.1016/j.biocel.2014.03.020. Epub 2014 Mar 28. Pranke IM, Sermet-Gaudelus I
Biosynthesis of cystic fibrosis transmembrane conductance regulator.
Int J Biochem Cell Biol. 2014 Jul;52:26-38. doi: 10.1016/j.biocel.2014.03.020. Epub 2014 Mar 28., [PMID:24685677]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated chloride (Cl(-)) channel. Mutations of its gene lead to the disease of cystis fibrosis (CF) among which the most common is the deletion of phenylalanine at position 508 (Phe508del). CFTR is a multi-domain glycoprotein whose biosynthesis, maturation and functioning as an anion channel involve multi-level post-translational modifications of CFTR molecules and complex folding processes to reach its native, tertiary conformation. Only 20-40% of the nascent chains achieve folded conformation, while the remaining molecules are targeted for degradation by endoplasmic reticulum, lysosomes, or autophagy. A large number of mutations causing CF impair processing of CFTR. Growing knowledge of CFTR biosynthesis has enabled understanding the cellular basis of CF and has brought to light various potential targets for novel, promising therapies.

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1376 These splicing mutations (e.g. 3849 + 10 kb C ࢐ T, 3272-26 A ࢐ G, IVS8-5T, D565G and G576A) lead to variable levels of correctly spliced transcripts among different patients and among different organs of the same patient. 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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95 CFTR variant %Cases %Uctrls OR p-value %Cases w/N34S OR w/N34S p-value w/N34S CF/BD or BD/BD 2.5 0.1 31.9 ,0.0001 5.5 7.46 0.12 All CF 8.7 3.3 2.76 ,0.0001 16.4 5.65 ,0.0001 F508del CF 6.9 3.1 2.32 ,0.0001 14.5 5.13 ,0.0001 IVS8T5** CF 9.9 8.2 1.24 0.079 10.9 1.37 0.47 2789+5G.A CF 0.3 0.0 0.028 0.0 3849+10kbC.T CF 0.3 0.0 0.028 0.0 N1303K CF 0.3 0.0 0.027 0.0 621+1G.T CF 0.1 0.0 0.13 1.8 ,0.0001 2184delA CF 0.1 0.0 0.13 0.0 3120+1G.A CF 0.1 0.0 0.13 0.0 G551D CF 0.2 0.1 2.50 0.20 0.0 0.00 0.83 W1282X CF 0.2 0.1 2.50 0.20 0.0 0.00 0.83 G542X CF 0.2 0.0 0.059 0.0 R1162X CF 0.1 0.0 0.13 0.0 2183AA.G CF 0.0 0.1 0.17 0.0 0.00 0.83 All BD 14.2 9.8 1.50 0.002 25.5 4.63 ,0.0001 R75Q BD 6.3 6.2 1.02 0.30 16.4 2.97 0.003 S1235R BD 2.4 1.4 1.69 0.052 1.8 1.30 0.80 R117H CF/BD 2.3 0.7 3.49 0.0007 5.5 8.74 0.0002 L967S BD 1.1 0.2 6.87 0.002 1.8 11.17 0.014 L997F BD 0.8 1.0 0.82 0.26 1.8 1.84 0.55 D1152H BD 0.4 0.0 0.014 0.0 D1270N BD 0.3 0.2 1.25 0.29 0.0 0.00 0.71 R170H BD 0.3 0.0 0.028 0.0 R74Q BD 0.3 0.1 3.02 0.17 1.8 21.15 0.002 Other M470V 76.1 74.2 1.11 0.14 70.9 0.85 0.59 T854T 57.3 57.8 0.98 0.29 45.5 0.61 0.071 Q1463Q 39.6 39.5 1.01 0.30 40.0 1.02 0.94 1001+11C.T* 13.4 10.9 1.27 0.016 14.5 1.40 0.42 125G.C 10.3 9.7 1.07 0.26 12.7 1.36 0.45 P1290P 7.6 7.9 0.95 0.28 7.3 0.91 0.86 1716G.A 4.5 4.1 1.10 0.26 1.8 0.43 0.39 R668C 1.0 1.4 0.72 0.19 0.0 0.00 0.38 G576A 0.7 1.2 0.58 0.11 0.0 0.00 0.41 computationally modeled the molecular structure, and studied the dynamics, of wild type (WT) and mutated CFTR channels. 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] Exercise intolerance, malnutrition, abnormal sweat... J Pediatr Health Care. 2015 Mar-Apr;29(2):201-4. doi: 10.1016/j.pedhc.2014.05.010. Epub 2014 Jul 22. Com G, Uc A
Exercise intolerance, malnutrition, abnormal sweat chloride levels, and two CFTR mutations: is it cystic fibrosis?
J Pediatr Health Care. 2015 Mar-Apr;29(2):201-4. doi: 10.1016/j.pedhc.2014.05.010. Epub 2014 Jul 22., [PMID:25060775]

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31 A full CFTR mutation panel revealed heterozygous mutations of p.G576A and p.R668C. Login to comment
45 Meanwhile, his CFTR gene mutation information was researched on two CF mutation databases (www.genet.sickkids.on.ca and www.cftr2.org), and it was found that neither p.G576A nor p.R668C mutations were associated with clinically significant disease. Login to comment

[hide] Improving newborn screening for cystic fibrosis us... Genet Med. 2015 Feb 12. doi: 10.1038/gim.2014.209. Baker MW, Atkins AE, Cordovado SK, Hendrix M, Earley MC, Farrell PM
Improving newborn screening for cystic fibrosis using next-generation sequencing technology: a technical feasibility study.
Genet Med. 2015 Feb 12. doi: 10.1038/gim.2014.209., [PMID:25674778]

Abstract [show]
Purpose:Many regions have implemented newborn screening (NBS) for cystic fibrosis (CF) using a limited panel of cystic fibrosis transmembrane regulator (CFTR) mutations after immunoreactive trypsinogen (IRT) analysis. We sought to assess the feasibility of further improving the screening using next-generation sequencing (NGS) technology.Methods:An NGS assay was used to detect 162 CFTR mutations/variants characterized by the CFTR2 project. We used 67 dried blood spots (DBSs) containing 48 distinct CFTR mutations to validate the assay. NGS assay was retrospectively performed on 165 CF screen-positive samples with one CFTR mutation.Results:The NGS assay was successfully performed using DNA isolated from DBSs, and it correctly detected all CFTR mutations in the validation. Among 165 screen-positive infants with one CFTR mutation, no additional disease-causing mutation was identified in 151 samples consistent with normal sweat tests. Five infants had a CF-causing mutation that was not included in this panel, and nine with two CF-causing mutations were identified.Conclusion:The NGS assay was 100% concordant with traditional methods. Retrospective analysis results indicate an IRT/NGS screening algorithm would enable high sensitivity, better specificity and positive predictive value (PPV). This study lays the foundation for prospective studies and for introducing NGS in NBS laboratories.Genet Med advance online publication 12 February 2015Genetics in Medicine (2015); doi:10.1038/gim.2014.209.

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32 [1075C>A;1079C>A] (Q359K/T360K) - - - Mutations that do not cause CF when combined with another CF-causing mutation c.1727G>C (G576A) c.3485G>T (R1162L) c.224G>A (R75Q) - - c.3080T>C (I1027T) c.91C>T (R31C) c.3705T>G (S1235R) - - c.2991G>C (L997F) c.2002C>T (R668C) c.2260G>A (V754M) - - Mutations/variants that were validated in this study are in bold. CF, cystic fibrosis. Table 1ߒContinued (http://www.hgvs.org/mutnomen/) and legacy mutation nomenclature (http://www.cftr2.org/browse.php). Login to comment

[hide] Comparative ex vivo, in vitro and in silico analys... J Cyst Fibros. 2015 Feb 27. pii: S1569-1993(15)00039-9. doi: 10.1016/j.jcf.2015.02.002. Ramalho AS, Clarke LA, Sousa M, Felicio V, Barreto C, Lopes C, Amaral MD
Comparative ex vivo, in vitro and in silico analyses of a CFTR splicing mutation: Importance of functional studies to establish disease liability of mutations.
J Cyst Fibros. 2015 Feb 27. pii: S1569-1993(15)00039-9. doi: 10.1016/j.jcf.2015.02.002., [PMID:25735457]

Abstract [show]
The Cystic Fibrosis p.Ile1234Val missense mutation actually creates a new dual splicing site possibly used either as a new acceptor or donor. Here, we aimed to test the accuracy of in silico predictions by comparing them with in vitro and ex vivo functional analyses of this mutation for an accurate CF diagnosis/prognosis. To this end, we applied a new in vitro strategy using a CFTR mini-gene which includes the complete CFTR coding sequence plus intron 22 (short version) which allows the assessment of alternatively spliced mRNA levels as well as the properties of the resulting abnormal CFTR protein regarding processing, intracellular localization and function. Our data demonstrate that p.Ile1234Val leads to usage of the alternative splicing donor (but not acceptor) resulting in alternative CFTR transcripts lacking 18nts of exon 22 which produce a truncated CFTR protein with residual Cl- channel function. These results recapitulate data from native tissues of a CF patient. In conclusion, the existing in silico prediction models have limited application and ex vivo functional assessment of mutation effects should be made. Alternatively the in vitro strategy adopted here can be applied to assess the disease liability of mutations for an accurate CF diagnosis/prognosis.

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31 Indeed, it was demonstrated that several CFTR missense mutations also alter splicing, e.g., p.Asp565Gly and p.Gly576Ala [20], p.Asp648Val and p.Thr665Ser [21] as well as p.Gly893Gly (c.2811 G N T) [22]. Login to comment

[hide] Should diffuse bronchiectasis still be considered ... J Cyst Fibros. 2015 Sep;14(5):646-53. doi: 10.1016/j.jcf.2015.02.012. Epub 2015 Mar 18. Bergougnoux A, Viart V, Miro J, Bommart S, Molinari N, des Georges M, Claustres M, Chiron R, Taulan-Cadars M
Should diffuse bronchiectasis still be considered a CFTR-related disorder?
J Cyst Fibros. 2015 Sep;14(5):646-53. doi: 10.1016/j.jcf.2015.02.012. Epub 2015 Mar 18., [PMID:25797027]

Abstract [show]
BACKGROUND: Although several comprehensive studies have evaluated the role of the CFTR gene in idiopathic diffuse bronchiectasis (DB), it remains controversial. METHODS: We analyzed the whole coding region of the CFTR gene, its flanking regions and the promoter in 47 DB patients and 47 controls. Available information about demographic, spirometric, radiological and microbiological data for the DB patients was collected. Unclassified CFTR variants were in vitro functionally assessed. RESULTS: CFTR variants were identified in 24 DB patients and in 27 controls. DB variants were reclassified based on the results of in silico predictive analyses, in vitro functional assays and data from epidemiological and literature databases. Except for the sweat test value, no clear genotype-phenotype correlation was observed. CONCLUSIONS: DB should not be considered a classical autosomal recessive CFTR-RD. Moreover, although further investigations are necessary, we proposed a new class of "Non-Neutral Variants" whose impact on lung disease requires more studies.

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77 (=) IVS8-(T)n no rs NA NA NA NA UV UV (ND) c.1519_1521delATC p.Ile507del I507del/ƊI507 rs121908745 0.021 0 NA 0.0024 (n2) 0.0038 (n3) CF CF (ND) c.1521_1523delCTT p.Phe508del F508del/ƊF508 rs113993960 0.01 0 0.01 (calculated) 0.67 (n1) CF CF c.1584G N A p.Glu528Glu 1716G N A rs1800095 0.021 0.0638 0.005-0.042 (15 studies) 0 (n1) P NNV c.1727G N C p.Gly576Ala G576A rs1800098 0.0638 0.0213 0.003-0.33 (4 studies) 0 (n1) UV M c.2002C N T p.Arg668Cys R668C rs1800100 0.0638 0.0319 0.004-0.02 (14 studies) 0 (n1) UV M c.2620-26A N G p. Login to comment
93 The UVs p.Gly576Ala and p.Arg668Cys were found in six patients with DB and two controls. Login to comment
95 [Gly576Ala;p.Arg668Cys] [8,17]; however no familial segregation was available for the present study. Login to comment
110 The results of this analysis and comparison, when possible, with the MAF range for the general population (dbSNP database) or the CF population (our laboratory cohort or previously published control cohorts [10,11]) indicated that the variants p.Arg75Gln, p.Gly576Ala and p.Arg668Cys were twice more present in the DB cohort than in the general population. Login to comment
136 Splicing was altered in the minigenes containing the exonic variants p.Gly576Ala, p.Arg668Cys and, to a lesser extent, p.Thr966Thr. Login to comment
137 For p.Gly576Ala, complete exon 13 skipping was observed, as previously described [19], although the bioinformatics analysis predicted no dramatic change. Login to comment
142 Moreover, for the variants p.Gly576Ala and p.Arg668Cys, the quantity of normal CFTR transcript was reduced by 57 and 37%, respectively, compared to the WT gene (Fig. 2C). Login to comment
148 Transfection of full length CFTR containing the mutation p.Arg75Gln, p.Gly576Ala/p.Arg668Cys (alone and together), p.Val754Met or p.Thr966Thr induced a 30-50% decrease in CFTR mRNA level, compared to WT CFTR (Fig. 2C). Login to comment
153 Quantification of the blots indicated that the level of mature CFTR protein was decreased by 17%-26% in cells expressing the p.Arg75Gln, p.Arg117His, p.Gly576Ala, p.Arg668Cys (alone and together), p.Leu997Phe or p.Thr966Thr variant, and by 48% and 39% in cells expressing p.Glu528Glu and p.Val754Met, respectively (Fig. 2D, lower panel). Login to comment
159 [Gly576Ala;p.Arg668Cys] complex allele and the p.Leu997Phe missense mutation [22]. Login to comment
185 Minigene splicing assays in Beas-2B cells to compare the effect of the p.Gly576Ala, p.Arg668Cys and p.Thr966Thr and wild type (WT) CFTR minigenes on the splicing patterns of exons 13, 14 and 16, respectively. Login to comment

[hide] Benign outcome among positive cystic fibrosis newb... J Cyst Fibros. 2015 Nov;14(6):714-9. doi: 10.1016/j.jcf.2015.03.006. Epub 2015 Mar 29. Salinas DB, Sosnay PR, Azen C, Young S, Raraigh KS, Keens TG, Kharrazi M
Benign outcome among positive cystic fibrosis newborn screen children with non-CF-causing variants.
J Cyst Fibros. 2015 Nov;14(6):714-9. doi: 10.1016/j.jcf.2015.03.006. Epub 2015 Mar 29., [PMID:25824995]

Abstract [show]
BACKGROUND: The Clinical and Functional Translation of CFTR project (CFTR2) classified some cystic fibrosis transmembrane conductance regulator (CFTR) gene variants as non-cystic fibrosis (CF)-causing. To evaluate this, the clinical status of children carrying these mutations was examined. METHODS: We analyzed CF disease-defining variables over 2-6 years in two groups of California CF screen- positive neonates born from 2007 to 2011: (1) children with two CF-causing variants and (2) children with one CF-causing and one non-CF-causing variant, as defined by CFTR2. RESULTS: Children carrying non-CF-causing variants had significantly higher birth weight, lower immunoreactive trypsinogen and sweat chloride values, higher first year growth curves, and a lower rate of persistent Pseudomonas aeruginosa colonization compared to children with two CF-causing variants. CONCLUSIONS: The outcomes in children 2-6 years of age with the L997F, G576A, R1162L, V754M, R668C, R31C, and S1235R variants are consistent with the CFTR2 non-CF-causing classification.

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4 Conclusions: The outcomes in children 2-6 years of age with the L997F, G576A, R1162L, V754M, R668C, R31C, and S1235R variants are consistent with the CFTR2 non-CF-causing classification. Login to comment
55 There were no sweat chloride results meeting CF diagnostic criteria of ࣙ60 mmol/L in the N-CF group, and only one subject with three variants (G542X, G576A, R668C) had values in the "possible CF" category (ࣙ40 mmol/L) beyond 6 months. Login to comment
96 a All subjects who had G576A from this study also had R668C in cis. Login to comment
97 Two other subjects had R668C without G576A. Login to comment
98 G576A and R668C were analyzed as single alleles in CFTR2. Login to comment

[hide] A Genotypic-Oriented View of CFTR Genetics Highlig... Mol Med. 2015 Apr 21;21:257-75. doi: 10.2119/molmed.2014.00229. Lucarelli M, Bruno SM, Pierandrei S, Ferraguti G, Stamato A, Narzi F, Amato A, Cimino G, Bertasi S, Quattrucci S, Strom R
A Genotypic-Oriented View of CFTR Genetics Highlights Specific Mutational Patterns Underlying Clinical Macrocategories of Cystic Fibrosis.
Mol Med. 2015 Apr 21;21:257-75. doi: 10.2119/molmed.2014.00229., [PMID:25910067]

Abstract [show]
Cystic fibrosis (CF) is a monogenic disease caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The genotype-phenotype relationship in this disease is still unclear, and diagnostic, prognostic and therapeutic challenges persist. We enrolled 610 patients with different forms of CF and studied them from a clinical, biochemical, microbiological and genetic point of view. Overall, there were 125 different mutated alleles (11 with novel mutations and 10 with complex mutations) and 225 genotypes. A strong correlation between mutational patterns at the genotypic level and phenotypic macrocategories emerged. This specificity appears to largely depend on rare and individual mutations, as well as on the varying prevalence of common alleles in different clinical macrocategories. However, 19 genotypes appeared to underlie different clinical forms of the disease. The dissection of the pathway from the CFTR mutated genotype to the clinical phenotype allowed to identify at least two components of the variability usually found in the genotype-phenotype relationship. One component seems to depend on the genetic variation of CFTR, the other component on the cumulative effect of variations in other genes and cellular pathways independent from CFTR. The experimental dissection of the overall biological CFTR pathway appears to be a powerful approach for a better comprehension of the genotype-phenotype relationship. However, a change from an allele-oriented to a genotypic-oriented view of CFTR genetics is mandatory, as well as a better assessment of sources of variability within the CFTR pathway.

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53 The controversial complex allele [1249-8A>G; G576A;R668C] (c. Login to comment
308 The complex allele [G576A;R668C] (p. Login to comment
309 [Gly576Ala;Arg668Cys]) (without the first mutation in cis) was found in two CFTR-RD patients with F508del (p.Phe508del) and S1235R (p.Ser1235Arg) on the other allele, with sweat tests, respectively, of 19 &#b1; 2 and 17 &#b1; 1 mEq/L (average 18 &#b1; 1 mEq/L). Login to comment
373 [1117-8A>G;1727G>C;2002C>T] uncertain: found only with an unknown allele in trans 1249-8A>G nd; G576A non CF-causing; R668C non CF-causing 1259insA c.1127_1128insA CF-PI CF-causing p.Gln378AlafsX4 E379X c.1135G>T CF-PI nd p.Glu379* M394R c.1181T>G CF-PI nd p.Met394Arg (TG)11T5 c. Login to comment
383 L571S c.1712T>C CF-PI nd p.Leu571Ser [G576A;R668C] c. Login to comment
384 [1727G>C;2002C>T] CFTR-RD G576A non CF-causing; R668C non-CF causing p. Login to comment
385 [Gly576Ala;Arg668Cys] D579G c.1736A>G CF-PS varying clinical consequence p.Asp579Gly E585X c.1753G>T CF-PI CF-causing p.Glu585* H609L c.1826A>T CFTR-RD nd p.His609Leu A613T c.1837G>A CF-PS nd p.Ala613Thr D614G c.1841A>G CF-PS unknown significance p.Asp614Gly 2143delT c.2012delT CF-PS CF-causing p.Leu671* 2183AA>G c.2051_2052delAAinsG CF-PI,CF-PS CF-causing p.Lys684SerfsX38 2184insA c.2052_2053insA CF-PI CF-causing p.Gln685ThrfsX4 R709X c.2125C>T CF-PI CF-causing p.Arg709* L732X c.2195T>G CF-PI CF-causing p.Leu732* R764X c.2290C>T CF-PI CF-causing p.Arg764* Q779X c.2335C>T uncertain: CF-PI and/or CF-PS nd p.Gln779* E831X c.2491G>T CF-PS CF-causing p.Glu831* Y849X c.2547C>A CF-PI CF-causing p.Tyr849* ex14b-17bdel c.2620-674_3367+198del9858 CF-PI nd 2789+5G>A c.2657+5G>A CF-PI,CF-PS CF-causing 2790-2A>G c.2658-2A>G CF-PS nd S912L c.2735C>T uncertain: found only with an unknown allele in trans nd p.Ser912Leu S945L c.2834C>T CF-PS CF-causing p.Ser945Leu S977F c.2930C>T CFTR-RD varying clinical consequence p.Ser977Phe L997F c.2991G>C CF-PS,CFTR-RD,CBAVD non CF-causing p.Leu997Phe ex17a-18del c.2988+1173_3468+2111del8600 CF-PI nd P1013L c.3038C>T CFTR-RD nd p.Pro1013Leu Y1032C c.3095A>G CFTR-RD nd p.Tyr1032Cys 3272-26A>G c.3140-26A>G CF-PS CF-causing L1065P c.3194T>C CF-PI,CF-PS CF-causing p.Leu1065Pro L1065R c.3194T>G uncertain: CF-PI and/or CF-PS nd p.Leu1065Arg R1066C c.3196C>T CF-PI CF-causing p.Arg1066Cys R1066H c.3197G>A CF-PI CF-causing p.Arg1066His G1069R c.3205G>A uncertain: found only with an unknown allele in trans varying clinical consequence p.Gly1069Arg Continued on next page of 0.021). Login to comment

[hide] Inconclusive diagnosis of cystic fibrosis after ne... Pediatrics. 2015 Jun;135(6):e1377-85. doi: 10.1542/peds.2014-2081. Epub 2015 May 11. Ooi CY, Castellani C, Keenan K, Avolio J, Volpi S, Boland M, Kovesi T, Bjornson C, Chilvers MA, Morgan L, van Wylick R, Kent S, Price A, Solomon M, Tam K, Taylor L, Malitt KA, Ratjen F, Durie PR, Gonska T
Inconclusive diagnosis of cystic fibrosis after newborn screening.
Pediatrics. 2015 Jun;135(6):e1377-85. doi: 10.1542/peds.2014-2081. Epub 2015 May 11., [PMID:25963003]

Abstract [show]
OBJECTIVES: To prospectively study infants with an inconclusive diagnosis of cystic fibrosis (CF) identified by newborn screening (NBS; "CF screen positive, inconclusive diagnosis" [CFSPID]) for disease manifestations. METHODS: Infants with CFSPID and CF based on NBS from 8 CF centers were prospectively evaluated and monitored. Genotype, phenotype, repeat sweat test, serum trypsinogen, and microbiology data were compared between subjects with CF and CFSPID and between subjects with CFSPID who did (CFSPID-->CF) and did not (CFSPID-->CFSPID) fulfill the criteria for CF during the first 3 years of life. RESULTS: Eighty-two subjects with CFSPID and 80 subjects with CF were enrolled. The ratio of CFSPID to CF ranged from 1:1.4 to 1:2.9 in different centers. CFTR mutation rates did not differ between groups; 96% of subjects with CFSPID and 93% of subjects with CF had 2 mutations. Subjects with CFSPID had significantly lower NBS immunoreactive trypsinogen (median [interquartile range]:77 [61-106] vs 144 [105-199] mug/L; P < .0001) than did subjects with CF. Pseudomonas aeruginosa and Stenotrophomonas maltophilia were isolated in 12% and 5%, respectively, of subjects with CFSPID. CF was diagnosed in 9 of 82 (11%) subjects with CFSPID (genotype and abnormal sweat chloride = 3; genotype alone = 4; abnormal sweat chloride only = 2). Sweat chloride was abnormal in CFSPID-->CF patients at a mean (SD) age of 21.3 (13.8) months. CFSPID-->CF patients had significantly higher serial sweat chloride (P < .0001) and serum trypsinogen (P = .009) levels than did CFSPID-->CFSPID patients. CONCLUSIONS: A proportion of infants with CFSPID will be diagnosed with CF within the first 3 years. These findings underscore the need for clinical monitoring, repeat sweat testing at age 2 to 3 years, and extensive genotyping.

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103 In combination with a disease-causing mutation, R117H-7T has been associated with diagnostic uncertainties in CF, TABLE 2 Genotypes of Subjects With CFSPID According to Initial Sweat Chloride Measurements Sweat Chloride ,30 mmol/L Sweat Chloride 30-59 mmol/L Allele 1 Allele 2 n Allele 1 Allele 2 n F508dela R117H (7T)b 9 F508dela R117Cd 2c F508dela 5Tb 2 F508dela L206Wd 2c F508dela D1152Hb 2 F508dela P67Ld 1c F508dela R117Hb 1 F508dela 5Tb 8 F508dela D1270Nb 1 F508dela R117H (7T)b 3 F508dela L997F 3 F508dela R117Hb 3 F508dela 1716G.A 1 F508dela S1455X 1c F508dela 621+3G.A 1 F508dela R170H 1 F508dela I1328T 1 F508dela I148T 1 F508dela L967S 1 F508dela L997F 1 F508dela M1137T 1 F508dela Q1476X 1 F508dela Y301C 1 F508dela S1235R 1 1717-1G.Aa D1152Hb 1 F508dela T1299I 1 2183AA.Ga 5Tb 1 2183AA.Ga R117Cd 1 2183AA.Ga S431G 1 2789+5G.Aa R117H (7T)b 1 3849+10kbC.Ta 3041-15T.G 1 3849+10kbC.Ta 3041-15T.G 1 621+1G.Ta R117H (7T)b 1 621+1G.Ta G1069Rb 1 711+1G.Ta D1152Hb 1 G542Xa L206Wd 1c G542Xa R117H (7T)b 1 G542Xa C1410T 1 G542Xa D1152Hb 1 G551Da 5Tb 1 G551Da D1152Hb 1 N1303Ka 5Tb 1 N1303Ka D1152Hb 1 R1162Xa R117H (7T)b 1c N1303Ka E527G 1 R553Xa 5Tb 1 R117H (5T)a 5Tb 1 R553Xa L997F 1 R117H (7T)b R117H (7T)b 1 R560Ta G576A 1 R117H (7T)b 3041_71G.C 1 W1282Xa 5Tb 2 R117Hb Q1476X 1 F508dela - 2 R117H (5T)a - 1 -, no mutation identified on the second allele. 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]

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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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87 [Gln359Lys; Thr360Lys] L558S c.1673 T4C p.Leu558Ser Y569D c.1705 T4G p.Tyr569Asp D579G c.1736 A4G p.Asp579Gly D614G c.1841 A4G p.Asp614Gly S977F c.2930C4T p.Ser977Phe F1052V c.3154 T4G p.Phe1052Val G1069R c.3205G4A p.Gly1069Arg R1070Q c.3209G4A p.Arg1070Gln D1152H c.3454G4C p.Asp1152His I1234V c.3700 A4G p.Ile1234Val 5T c.1210 - 12[5] Examples of common not CF-causing variantsc R31C c.91C4T p.Arg31Cys R74W c.220C4T p.Arg74Trp R75Q c.224G4A p.Arg75Gln I148T c.443 T4C p.Ile148Thr M470V c.1408 A4G p.Met470Val G576A c.1727G4C p.Gly576Ala R668C c.2002C4T p.Arg668Cys V754M c.2260G4A p.Val754Met L997F c.2991G4C p.Leu997Phe I1027T c.3080 T4C p.Ile1027Thr R1070W c.3208C4T p.Arg1070Trp R1162L c.3485G4T p.Arg1162Leu Table 1 (Continued) HGVS nomenclature Legacy name cDNA nucleotide name Protein name S1235R c.3705 T4G p.Ser1235Arg D1270N c.3808G4A p.Asp1270Asn 7T c.1210-12[7] Abbreviation: HGVS, Human Genome Variation Society. Login to comment
103 [220C4T;c.3208C4T;3808G4A] I148T is a neutral variant, but can be associated in cis with a severe CF variant c.3067_3072del (legacy 3199del6 or 3195del6) that, in isolation causes CF, whereas I148T in isolation does not.19,20 G576A is found in cis with R668C and R668C can be found alone or in cis with G576A. Login to comment

[hide] Identification and frequencies of cystic fibrosis ... Clin Biochem. 2015 Oct 21. pii: S0009-9120(15)00473-7. doi: 10.1016/j.clinbiochem.2015.10.007. Pepermans X, Mellado S, Chialina S, Wagener M, Gallardo L, Lande H, Bordino W, Baran D, Bours V, Leal T
Identification and frequencies of cystic fibrosis mutations in central Argentina.
Clin Biochem. 2015 Oct 21. pii: S0009-9120(15)00473-7. doi: 10.1016/j.clinbiochem.2015.10.007., [PMID:26500004]

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84 In one patient, the variants c.1727G N C (p.Gly576Ala) and c.2002C N T (p.Arg668Cys) were observed. Login to comment
100 [1727G N C(;)2002C N T] G576A-R668C 1 (0.6) No Yes in trans non CF-causing in trans No p.Ser589Ile c.1766G N T S589I 1 (0.6) No Yes No No NA c.1766 + 1G N A 1898 + 1G N A 1 (0.6) Yes Yes CF-causing rs186089140 p.Ser737Phe c.2210C N T S737F 1 (0.6) No Yes No rs397508376 p.Leu812Phefs*11 c.2434_2435insT 2566insT 1 (0.6) No Yes No No p.Ser821Argfs*4 c.2462_2463delGT 2594delGT 1 (0.6) No Yes CF-causing No p.Tyr852Leufs*44 c.2554dupT c.2554dupT &#a7; 1 (0.6) No No No rs80224560 NA c.2657 + 5G N A 2789 + 5G N A 1 (0.6) No Yes CF-causing rs75096551 NA c.2988 + 1G N A 3120 + 1G N A 1 (0.6) Yes Yes CF-causing rs76151804 NA c.3140-26A N G 3272-26A N G 1 (0.6) No Yes CF-causing rs143570767 NA c.3873 + 1G N A 4005 + 1G N A 1 (0.6) No Yes CF-causing rs397508631 p.Ser1297Phefs*5 c.3884_3885insT 4016insT 1 (0.6) No Yes CF-causing No p.Leu1414Phe c.4242_4242 + 1delGGinsTT 4374_4374 + 1GG N TT 1 (0.6) No Yes No No NA c.1210-12T [5] TG11-5T 1 (0.6) Yes Yes Varying clinical consequence - p.= c.= WT 14 (8.4) NA NA NA HGVS (Human Genoma Variation Society) used for protein nomenclature [15,16]. Login to comment

[hide] Newborn Screening for Cystic Fibrosis in Californi... Pediatrics. 2015 Dec;136(6):1062-72. doi: 10.1542/peds.2015-0811. Epub 2015 Nov 16. Kharrazi M, Yang J, Bishop T, Lessing S, Young S, Graham S, Pearl M, Chow H, Ho T, Currier R, Gaffney L, Feuchtbaum L
Newborn Screening for Cystic Fibrosis in California.
Pediatrics. 2015 Dec;136(6):1062-72. doi: 10.1542/peds.2015-0811. Epub 2015 Nov 16., [PMID:26574590]

Abstract [show]
OBJECTIVES: This article describes the methods used and the program performance results for the first 5 years of newborn screening for cystic fibrosis (CF) in California. METHODS: From July 16, 2007, to June 30, 2012, a total of 2 573 293 newborns were screened for CF by using a 3-step model: (1) measuring immunoreactive trypsinogen in all dried blood spot specimens; (2) testing 28 to 40 selected cystic fibrosis transmembrane conductance regulator (CFTR) mutations in specimens with immunoreactive trypsinogen values >/=62 ng/mL (top 1.6%); and (3) performing DNA sequencing on specimens found to have only 1 mutation in step 2. Infants with >/=2 mutations/variants were referred to CF care centers for diagnostic evaluation and follow-up. Infants with 1 mutation were considered carriers and their parents offered telephone genetic counseling. RESULTS: Overall, 345 CF cases, 533 CFTR-related metabolic syndrome cases, and 1617 carriers were detected; 28 cases of CF were missed. Of the 345 CF cases, 20 (5.8%) infants were initially assessed as having CFTR-related metabolic syndrome, and their CF diagnosis occurred after age 6 months (median follow-up: 4.5 years). Program sensitivity was 92%, and the positive predictive value was 34%. CF prevalence was 1 in 6899 births. A total of 303 CFTR mutations were identified, including 78 novel variants. The median age at referral to a CF care center was 34 days (18 and 37 days for step 2 and 3 screening test-positive infants, respectively). CONCLUSIONS: The 3-step model had high detection and low false-positive levels in this diverse population.

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123 IRT below cutoff 14 9 / (mutations not identified) White (n = 5) Meconium ileus (n = 2) 9 / c.1727G.C (G576A)/ c.2002C.T (R668C) Hispanic (n = 3) Family history (n = 2) 16 / c.1521_1523delCTT (F508del)/ c.1624G.T (G5423) Other/multiple (n = 6) Symptoms (n = 12) 28 / c.1521_1523delCTT (F508del)/ c.1521_1523delCTT (F508del) 28 / c.14C.T (P5L)/ c.870-7_870-5delTTT (1002-7delTTT) 29 / (mutations not identified) 31 / c.1521_1523delCTT (F508del)/ c.2175_2176insA (2307insA) 31 / (mutation not identified)/ c. Login to comment