ABCMdb

ABCC7 p.Ala1067Thr

Admin's notes:	Class II-III (maturation defect, gating defect) Veit et al.
ClinVar:	c.3200C>T , p.Ala1067Val ? , not provided c.3199G>C , p.Ala1067Pro ? , not provided c.3200C>G , p.Ala1067Gly ? , not provided c.3200C>A , p.Ala1067Asp ? , not provided c.3199G>A , p.Ala1067Thr ? , Conflicting interpretations of pathogenicity, not provided
CF databases:	c.3200C>A , p.Ala1067Asp (CFTR1) D , This substitution involves a residue conserved among species, located in an intracellular loop, and affects the charge of the CFTR protein. It was found at the homozygous state in a patient originating from India, and having a classical severe form of CF. A1067D creates a MaeIII restriction site. c.3199G>C , p.Ala1067Pro (CFTR1) D , The mutation was detected by DHPLC analysis and characterized by direct seqencing c.3199G>A , p.Ala1067Thr (CFTR1) ? , This child is 2 years old, carries the [delta]F508 mutation on the other chromosome, and is at this time a mild form of the disease. c.3200C>G , p.Ala1067Gly (CFTR1) ? , This change has been detected by DGGE analysis and direct sequencing in one Spanish allele c.3200C>T , p.Ala1067Val (CFTR1) ? , Ala to Val at 1067
Predicted by SNAP2:	C: D (91%), D: D (95%), E: D (95%), F: D (95%), G: D (95%), H: D (95%), I: D (95%), K: D (95%), L: D (95%), M: D (95%), N: D (95%), P: D (95%), Q: D (95%), R: D (95%), S: D (91%), T: N (87%), V: D (71%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: N, T: D, V: D, W: D, Y: D,

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

Publications
[hide] Aberrant CFTR-dependent HCO3- transport in mutatio... Nature. 2001 Mar 1;410(6824):94-7. Choi JY, Muallem D, Kiselyov K, Lee MG, Thomas PJ, Muallem S
Aberrant CFTR-dependent HCO3- transport in mutations associated with cystic fibrosis.
Nature. 2001 Mar 1;410(6824):94-7., 2001-03-01 [PMID:11242048]

Abstract [show]
Cystic fibrosis (CF) is a disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). Initially, Cl- conductance in the sweat duct was discovered to be impaired in CF, a finding that has been extended to all CFTR-expressing cells. Subsequent cloning of the gene showed that CFTR functions as a cyclic-AMP-regulated Cl- channel; and some CF-causing mutations inhibit CFTR Cl- channel activity. The identification of additional CF-causing mutants with normal Cl- channel activity indicates, however, that other CFTR-dependent processes contribute to the disease. Indeed, CFTR regulates other transporters, including Cl(-)-coupled HCO3- transport. Alkaline fluids are secreted by normal tissues, whereas acidic fluids are secreted by mutant CFTR-expressing tissues, indicating the importance of this activity. HCO3- and pH affect mucin viscosity and bacterial binding. We have examined Cl(-)-coupled HCO3- transport by CFTR mutants that retain substantial or normal Cl- channel activity. Here we show that mutants reported to be associated with CF with pancreatic insufficiency do not support HCO3- transport, and those associated with pancreatic sufficiency show reduced HCO3- transport. Our findings demonstrate the importance of HCO3- transport in the function of secretory epithelia and in CF.

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36 Similar rates were measured for the I148T, G178R, A1067T, G1244E, S1255P and G1349D mutants (see Fig. 3 for location of these mutations in CFTR), all of which are associated with CF with pancreatic insuf®- ciency. Login to comment
186 letters to nature 96 NATURE |VOL 410 |1 MARCH 2001 |www.nature.com HCO3 -/Cl- transportratio 0 0.25 0.50 0.75 1.00 WT I148T G178R R297Q G551D H620Q G970R A1067T G1244E S1255P G1349D E193K G551S A800G H949Y R1070Q Pancreatic insufficient Pancreatic sufficientD648V N CI148T G178R E193K R297Q R117H A1067T R1070Q G1244E S1255P G1349D NBD2 RD H949Y G970R CL4CL3CL2CL1 NBD1 G551D G551S H620Q D648V A800G Figure 3 The HCO3:Cl-transport ratio of CFTR mutants associated with CF. Login to comment

[hide] Misfolding of the cystic fibrosis transmembrane co... Biochemistry. 2008 Feb 12;47(6):1465-73. Epub 2008 Jan 15. Cheung JC, Deber CM
Misfolding of the cystic fibrosis transmembrane conductance regulator and disease.
Biochemistry. 2008 Feb 12;47(6):1465-73. Epub 2008 Jan 15., 2008-02-12 [PMID:18193900]

Abstract [show]
Understanding the structural basis for defects in protein function that underlie protein-based genetic diseases is the fundamental requirement for development of therapies. This situation is epitomized by the cystic fibrosis transmembrane conductance regulator (CFTR)-the gene product known to be defective in CF patients-that appears particularly susceptible to misfolding when its biogenesis is hampered by mutations at critical loci. While the primary CF-related defect in CFTR has been localized to deletion of nucleotide binding fold (NBD1) residue Phe508, an increasing number of mutations (now ca. 1,500) are being associated with CF disease of varying severity. Hundreds of these mutations occur in the CFTR transmembrane domain, the site of the protein's chloride channel. This report summarizes our current knowledge on how mutation-dependent misfolding of the CFTR protein is recognized on the cellular level; how specific types of mutations can contribute to the misfolding process; and describes experimental approaches to detecting and elucidating the structural consequences of CF-phenotypic mutations.

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90 In some additional examples, a number of mutations found in the fourth intracellular loop (H1054D, G1061R, L1065P, R1066C/H/L, Q1071P, L1077P, H1085R, W1098R, M1101K/ R) also affect the biosynthetic processing of CFTR (although function was not tested) (73); some intracellular loop 4 mutants (F1052V, K1060T, A1067T, G1069R, R1070Q/W) can process CFTR to the complex-glycosylated ("Band C") form but have altered channel activity compared to wild type. Login to comment

[hide] Validation of double gradient denaturing gradient ... Clin Chem. 1999 Jan;45(1):35-40. Cremonesi L, Carrera P, Fumagalli A, Lucchiari S, Cardillo E, Ferrari M, Righetti SC, Zunino F, Righetti PG, Gelfi C
Validation of double gradient denaturing gradient gel electrophoresis through multigenic retrospective analysis.
Clin Chem. 1999 Jan;45(1):35-40., [PMID:9895335]

Abstract [show]
Among established techniques for the identification of either known or new mutations, denaturing gradient gel electrophoresis (DGGE) is one of the most effective. However, conventional DGGE is affected by major drawbacks that limit its routine application: the different denaturant gradient ranges and migration times required for different DNA fragments. We developed a modified version of DGGE for high-throughput mutational analysis, double gradient DGGE (DG-DGGE), by superimposing a porous gradient over the denaturant gradient, which maintains the zone-sharpening effect even during lengthy analyses. Because of this innovation, DG-DGGE achieves the double goals of retaining full effectiveness in the detection of mutations while allowing identical run time conditions for all fragments analyzed. Here we use retrospective analysis of a large number of well-characterized mutations and polymorphisms, spanning all predicted melting domains and the whole genomic sequence of three different genes--the cystic fibrosis transmembrane conductance regulator (CFTR), the beta-globin, and the p53 genes--to demonstrate that DG-DGGE may be applied to the rapid scanning of any sequence variation.

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31 Mutations and polymorphisms analyzed in the CFTR gene. Position Denaturant gradient Mutation Exon 1 40-90% 125G/Ca,b M1V (A3G at 133) 175insT 182delT Exon 3 10-60% W57G (T3G at 301) 356G/Aa G85E (G3A at 386) Exon 4 20-70% R117H (G3A at 482) 541delC 621ϩ1G3T I148T (T3C at 575) Exon 5 20-70% E193K (G3A at 709) Intron 5 20-70% 711ϩ3A3G Exon 7 20-70% 1078delT R334W (C3T at 1132) T338I (C3T at 1145) R347P (G3C at 1172)b R347H (G3A at 1172) R352Q (G3A at 1187) Exon 10 20-70% M470V (1540A/G)a ⌬F508 (del 3 bp at 1652) Intron 10 10-60% 1717-1G3A Exon 11 10-60% G542X (G3T at 1756) 1784delG R553X (C3T at 1789) Exon 12 10-60% D579G (A3G at 1868) E585X (G3T at 1885) Intron 12 10-60% 1898ϩ3A3G Exon 13 30-80% 2183AA3G E730X (G3T at 2320) L732X (T3G at 2327) 2347delG Exon 14a 10-60% T854T (2694T/G)a V868V (2736G/A)a Intron 14b 30-80% 2789ϩ5G3A Exon 15 20-70% M952I (G3C at 2988)b Exon 17a 20-70% L997F (G3C at 3123)b Exon 17b 20-70% F1052V (T3G at 3286) R1066C (C3T at 3328) R1066H (G3A at 3329) A1067T (G3A at 3331) Exon 18 20-70% D1152H (G3C at 3586)b Exon 19 30-80% R1158X (C3T at 3604) Exon 20 20-70% S1251N (G3A at 3384) W1282X (G3A at 3978) Exon 21 20-70% N1303K (C3G at 4041)b Exon 22 30-80% G1349D (G3A at 4178) 4382delA Exon 24 30-80% Y1424Y (4404C/T)a a Polymorphism. 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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63 Continued Exon Primer Sequences GC length Amplicon length (bp) Introns Number of heterozygous- positive controls Number of homozygous- positive controls Recommended control 16 LSCFE16Fmod 5Ј-CCGCTGAATGCGTCTACTGTGATCCA-3Ј 3 299 bp 77 6 G970R LSCFE16Rmod 5Ј-CCGTAGACAGGACTTCAA CCCTCAATCAA-3Ј 3 87 3120ϩ1GϾA 17a LSCFE17AFmod 5Ј-CCGCCGGACACACTTTG TCCACTT-3Ј 6 286 bp 49 13 3121-1GϾA LSCFE17ARmod 5Ј-CCGCCGTCAAATAGCTCTTATAGCTTTTTT ACAAGATG-3Ј 6 25 I1027T 17b LSCF17BAFmod 5Ј-CCGCCGCCCCGCCGTCAGGTACA AGATATTATG-3Ј 14 56 11 3272-26AϾG LSCF17BARmod 5Ј-CCGCCGCCGCAGTGTTGACAGGT ACAAGAAC-3Ј 7 247 bp A1067T LSCF17BBFmod 5Ј-CCGCCCTTACTTTGAAACTCTGTT CCACAAAGC-3Ј 4 247 bp T1095T LSCF17BBRmod 5Ј-CCGCCGTTGATAACCTATAGAATG CAG-3Ј 6 62 E1104X 18 LSCFE18Fmod 5Ј-CCGCCGAGTCGTTCACAGAAGA GAGAAATAAC-3Ј 6 236 bp 34 2 D1152H LSCFE18Rmod 5Ј-CCGCCGCCGCGGTACTTTGTT ACTTGTCTGAATTTTTTT-3ЈCATAA 12 25 3547delA 19 LSCF19i5mod 5Ј-CCGCCGCCGCGCATCAAACTA ATTGTGAAATTGTCTGCC-3Ј 10 408 bp 73 10 S1235R LSCF19i3mod 5Ј-CCGCCGCCGCACACATTGCT TCAGGCTACTGGGA-3Ј 11 49 R1162L 20 LSCF20i5mod 5Ј-CCGCCGCCGCCGCTACTGAATTATGT TTATGGCATGG-3Ј 13 323 bp 44 13 W1282X LSCF20i3mod 5Ј-CCGCCGCCGCTCTTGAGTACAAGTA TCAAATAGCAG-3Ј 10 50 4005ϩ33GϾA 21 LSCFe21F 5Ј-CCGCCGCCGCGCAAGTTATTCATA CTTTCTTCTTCTTT-3Ј 12 217 bp 15 5 1 N1303K LSCFe21R 5Ј-CCGCCGCCGCTATATCAGCCA TTTGTG-3Ј 8 47 Q1313X 22 LSCFe22FmodC LSCFe22 RmodD 5Ј-CCGCCGAGAATGTCAAC TGCTTGAGTGT-3Ј 6 311 bp 41 2 R1358S 5Ј-CCGCCGGCAGGCATAATGA TTCTGTTCCCAC-3Ј 10 51 I1366T 23 LSCFE23Fmod 5Ј-CCGCCGCCGCAAGGTAAAT ACAGATCAT-3Ј 9 259 bp 44 3 4374ϩ1GϾT 4374ϩ13AϾG LSCFE23Rmod: 5Ј-CCGGCAGGAACTATCACAT GTGAGATTG-3Ј 3 53 24 LSCFE24FmodB 5Ј-CCGCCGCTTTGAGCCTGT GCCAGTTTCTGT-3Ј 6 378 bp 58 5 1 Q1463Q LSE24RmodB 5Ј-CCGCCGACGAGCTCCAATTC CATGAGGTGA-3Ј 6 62 Y1424Y the same technique: the majority of our samples were extracted by a classical saline technique or an automated extraction and their quality was adequate. Login to comment

[hide] Novel Cystic Fibrosis mutation L1093P: functional ... Hum Mutat. 2000 Feb;15(2):208. Yee K, Robinson C, Hurlock G, Moss RB, Wine JJ
Novel Cystic Fibrosis mutation L1093P: functional analysis and possible Native American origin.
Hum Mutat. 2000 Feb;15(2):208., [PMID:10649505]

Abstract [show]
A novel mutation was detected using single-strand conformation polymorphism and heteroduplex analysis in a cystic fibrosis subject of mixed ancestry. Mutation 3410T-->C in exon 17b caused the novel missense mutation L1093P; the other chromosome has mutation N1303K. The 31-year-old subject is pancreatic insufficient, had an FEV(1) score that was 33% of normal prior to a heart/lung transplant, and sweat chloride values of 116 and 95 mM when tested at ages 1 and 11. Functional analysis using forskolin-stimulated efflux of (125)I in HEK cells transfected with an ABCC7 construct harboring the L1093P mutation confirmed that cAMP-mediated anion efflux was abnormal, but some function was preserved. Analysis of parental DNA established that N1303K was of English origin, while L1093P was of Greek, Irish or Native American (Cherokee) origin. Given the intensive screening for CF mutations in European populations, we hypothesize that L1093P is of Native American origin. Hum Mutat 15:208, 2000.

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78 Other mutations in this region e.g. A1067T (Cotton et al. 1996; Seibert et al. 1996) and Q1071P (Seibert et al. 1996) are associated with pancreatic insufficiency, yet retain partial function when tested with efflux assays. 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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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
129 Six sequence changes listed as mutations (CFGAC or personal communication) were detected on a chromosome carrying the 5T allele (G550R, A800G, T1053I, A1067T, S1235R, and 1717- 3T>G). Login to comment
152 Twenty-four non F508del mutations were found associated with the 9T allele: 394delTT, L90S, D110H, R117G, 621+1G>T, V232D, A455E, G542X, R851L, T908N, 2789+5G>A, 2896insAG, H939R, 3007delG, I980K, I1027T, R1066H, A1067T, D1154G, 3737delA, R74W+D1270N, N1303I, N1303K, D1377H. Login to comment

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

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

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6 Fourty-two of the 64 patients (65.6%) had mutations on both copies of the CFTR gene, including one patient with two mutations in the same copy (DF508 + A1067T). Login to comment
31 A double mutant allele was identified in one CBAVD patient (N°38 in table 1) with the DF508 associated to the mutation A1067T on the same chromosome inherited from his father, in trans with the 5T allele inherited from his mother. Login to comment

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

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

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98 A mutation in the adjacent residue A1067T caused a decrease in the P0 with a corresponding decrease in the burst duration. Login to comment

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

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

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84 In Fig. 2 the processing of ⌬F508 and the milder CF-associated mutant, P574H (10), are provided for reference. Login to comment
85 Whole Cell Function of ICL4 Mutants-To evaluate the effect of ICL4 mutations on Cl- channel activity, we selected the mutants R1066C, R1066H, R1066L, A1067T, and F1052V for study. Login to comment
95 We found that cells expressing all of the ICL4 mutants (F1052V, R1066C, R1066H, R1066L, and A1067T) generated cAMP-stimulated Cl- selective currents that showed time-and voltage-independent behavior identical to that of wild-type CFTR (data not shown). Login to comment
103 Mutations did not alter single-channel conductance: wild-type, 8.9 Ϯ 0.3 pS; F1052V, 9.6 Ϯ 0.2 pS; R1066C, 8.9 Ϯ 0.4 pS; R1066H, 8.5 Ϯ 0.7; R1066C, 8.6 Ϯ 0.3; and A1067T, 9.2 Ϯ 0.2 pS. Login to comment
105 Table I shows that F1052V, R1066L, and A1067T did not alter the relative permeability or conductivity sequence for Cl- , Br- , or I- . Login to comment
115 In contrast to the cysteine mutation, mutation of Arg-1066 to histidine did not significantly alter any of the kinetics and mutation to leucine produced a small decrease in burst duration and increase in fast closed time. Login to comment
116 Mutation of the adjacent residue Ala-1067 to threonine produced a different pattern; Po was decreased primarily because of a decrease in burst duration. Login to comment
134 R1066L and A1067T because they showed altered gating (Figs. 4 and 5); we did not study R1066C because it was difficult to study in excised, inside-out membrane patches, possibly because of its very low Po and poor processing. Login to comment
136 R1066L had a response identical to that of wild-type CFTR. Login to comment
137 The maximum Po of A1067T was decreased, but the shape of the concentration Po curve mirrored that of wild-type. Login to comment
139 This pattern of response for A1067T is similar to what we have found with the NBD mutants G551D, G1244E, and G1349D (8). Login to comment
140 The decrease in maximum Po without a change in the shape of the dose-response curve suggests that in A1067T ATP binding may be unaltered but that a step distal to binding may be affected. Login to comment
152 n Px/PCL Gx/GCL Br- Cl- IBr- ClI- Wild-type 3 1.29 Ϯ 0.07 1.00 0.56 Ϯ 0.13 1.18 Ϯ 0.56 1.00 0.35 Ϯ 0.06 F1052V 2 1.41 1.00 0.50 0.98 1.00 0.53 R1066L 4 1.36 Ϯ 0.07 1.00 0.88 Ϯ 0.11 1.15 Ϯ 0.22 1.00 0.40 Ϯ 0.11 A1067T 4 1.29 Ϯ 0.15 1.00 0.66 Ϯ 0.04 1.00 Ϯ 0.10 1.00 0.43 Ϯ 0.06 FIG. 4. Login to comment
156 Data are mean Ϯ S.E. of (6/5) measurements for Po and burst duration, respectively: wild-type (19/18), F1052V (6/5) R1066C (3/3), R1066H (6/7), R1066L (12/5), and A1067T (9/3). Login to comment
189 The fact that ICL4 and NBD2 mutants reduced the response to PPi and the finding that G1349D and A1067T altered the effect of increasing concentrations of ATP in a similar way further suggest some interaction between ICL4 and the NBDs, particularly NBD2. Login to comment
200 Data are mean Ϯ S.E. of (n) measurements for: wild-type (9), F1052V (3), R1066L (4), A1067T (4), G551S (6), K464A (4), G1349D (5), K1250 M at 5 mM PPi (5), wild-type at 5 mM PPi (16). Login to comment
202 Effect of increasing concentrations of ATP on Po for wild-type CFTR (squares), R1066L (circles), and A1067T (triangles). Login to comment
222 For example, H1085R is misprocessed like ⌬F508, yet it is reported to occur in a patient with a pancreatic sufficient phenotype. Login to comment
223 Conversely, our data with the mutants R1066L, R1066H, and A1067T are similar to that obtained with the "mild" mutants A455E and P574H (10) in that they retained partial processing and function. Login to comment
94 We found that cells expressing all of the ICL4 mutants (F1052V, R1066C, R1066H, R1066L, and A1067T) generated cAMP-stimulated Cl2 selective currents that showed time-and voltage-independent behavior identical to that of wild-type CFTR (data not shown). Login to comment
102 Mutations did not alter single-channel conductance: wild-type, 8.9 6 0.3 pS; F1052V, 9.6 6 0.2 pS; R1066C, 8.9 6 0.4 pS; R1066H, 8.5 6 0.7; R1066C, 8.6 6 0.3; and A1067T, 9.2 6 0.2 pS. Login to comment
104 Table I shows that F1052V, R1066L, and A1067T did not alter the relative permeability or conductivity sequence for Cl2 , Br2 , or I2 . Login to comment
133 CF-associated Mutations in ICL4 of CFTR R1066L and A1067T because they showed altered gating (Figs. 4 and 5); we did not study R1066C because it was difficult to study in excised, inside-out membrane patches, possibly because of its very low Po and poor processing. Login to comment
138 This pattern of response for A1067T is similar to what we have found with the NBD mutants G551D, G1244E, and G1349D (8). Login to comment
151 n Px/PCL Gx/GCL Br2 Cl2 I2 Br2 Cl2 I2 Wild-type 3 1.29 6 0.07 1.00 0.56 6 0.13 1.18 6 0.56 1.00 0.35 6 0.06 F1052V 2 1.41 1.00 0.50 0.98 1.00 0.53 R1066L 4 1.36 6 0.07 1.00 0.88 6 0.11 1.15 6 0.22 1.00 0.40 6 0.11 A1067T 4 1.29 6 0.15 1.00 0.66 6 0.04 1.00 6 0.10 1.00 0.43 6 0.06 FIG. 4. Login to comment
155 Data are mean 6 S.E. of (6/5) measurements for Po and burst duration, respectively: wild-type (19/18), F1052V (6/5) R1066C (3/3), R1066H (6/7), R1066L (12/5), and A1067T (9/3). Login to comment
188 The fact that ICL4 and NBD2 mutants reduced the response to PPi and the finding that G1349D and A1067T altered the effect of increasing concentrations of ATP in a similar way further suggest some interaction between ICL4 and the NBDs, particularly NBD2. Login to comment
199 Data are mean 6 S.E. of (n) measurements for: wild-type (9), F1052V (3), R1066L (4), A1067T (4), G551S (6), K464A (4), G1349D (5), K1250 M at 5 mM PPi (5), wild-type at 5 mM PPi (16). Login to comment
201 Effect of increasing concentrations of ATP on Po for wild-type CFTR (squares), R1066L (circles), and A1067T (triangles). Login to comment

[hide] Disease-associated mutations in the fourth cytopla... J Biol Chem. 1996 Jun 21;271(25):15139-45. Seibert FS, Linsdell P, Loo TW, Hanrahan JW, Clarke DM, Riordan JR
Disease-associated mutations in the fourth cytoplasmic loop of cystic fibrosis transmembrane conductance regulator compromise biosynthetic processing and chloride channel activity.
J Biol Chem. 1996 Jun 21;271(25):15139-45., [PMID:8662892]

Abstract [show]
A cluster of 18 point mutations in exon 17b of the cystic fibrosis transmembrane conductance regulator (CFTR) gene has been detected in patients with cystic fibrosis. These mutations cause single amino acid substitutions in the most C-terminal cytoplasmic loop (CL4, residues 1035-1102) of the CFTR chloride channel. Heterologous expression of the mutants showed that 12 produced only core-glycosylated CFTR, which was retained in the endoplasmic reticulum; the other six mutants matured and reached the cell surface. In some cases substitution of one member of pairs of adjacent residues resulted in misprocessing, whereas the other did not. Thus, the secondary structure of CL4 may contribute crucially to the proper folding of the entire CFTR molecule. Cyclic AMP-stimulated iodide efflux was not detected from cells expressing the misprocessed variants but was from the other six, indicating that their mutations cause relatively subtle channel defects. Consistent with this, these latter mutations generally are present in patients who are pancreatic-sufficient, while the processing mutants are mostly from patients who are pancreatic-insufficient. Single-channel patch-clamp analysis demonstrated that the processed mutants had the same ohmic conductance as wild-type CFTR, but a lower open probability, generally due to an increase in channel mean closed time and a reduction in mean open time. This suggests that mutations in CL4 do not affect pore properties of CFTR, but disrupt the mechanism of channel gating.

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64 The mature forms of the other six mutants (F1052V, K1060T, A1067T, G1069R, R1070W, R1070Q) were produced in relatively normal amounts (band C), although for A1067T and R1070W CFTR the ratio of the complex-glycosylated to core-glycosylated bands was significantly lower than for wild-type CFTR. Login to comment
82 A1067T, R1070W, and R1070Q CFTR had significantly lower efflux levels and significantly lower protein expression than wild-type CFTR in COS-1 cells. Login to comment
127 Symbols are as follows: A: छ, WT; E, F1052V; Ç, K1060T; µ, A1067T; Ⅺ, vector only control. Login to comment
142 A, examples of wild-type, F1052V, K1060T, A1067T, G1069R, R1070Q, and R1070W CFTR single channel currents recorded from inside-out membrane patches at a membrane potential of -30 mV. Login to comment
71 The mature forms of the other six mutants (F1052V, K1060T, A1067T, G1069R, R1070W, R1070Q) were produced in relatively normal amounts (band C), although for A1067T and R1070W CFTR the ratio of the complex-glycosylated to core-glycosylated bands was significantly lower than for wild-type CFTR. Login to comment
89 A1067T, R1070W, and R1070Q CFTR had significantly lower efflux levels and significantly lower protein expression than wild-type CFTR in COS-1 cells. Login to comment
133 Symbols are as follows: A: L, WT; E, F1052V; &#c7;, K1060T; &#b5;, A1067T; M, vector only control. Login to comment
148 A, examples of wild-type, F1052V, K1060T, A1067T, G1069R, R1070Q, and R1070W CFTR single channel currents recorded from inside-out membrane patches at a membrane potential of 230 mV. Login to comment

[hide] Neonatal screening for cystic fibrosis: result of ... Hum Genet. 1995 Nov;96(5):542-8. Ferec C, Verlingue C, Parent P, Morin JF, Codet JP, Rault G, Dagorne M, Lemoigne A, Journel H, Roussey M, et al.
Neonatal screening for cystic fibrosis: result of a pilot study using both immunoreactive trypsinogen and cystic fibrosis gene mutation analyses.
Hum Genet. 1995 Nov;96(5):542-8., [PMID:8530001]

Abstract [show]
We have evaluated a two-tier neonatal cystic fibrosis (CF) screening of immunoreactive trypsinogen (IRT) followed by CFTR gene mutation analysis using a systematic scanning of exons 7, 10, and 11, and, if necessary, by direct DNA sequencing. Over an 18-month period we screened 32,300 neonates born in the western part of Britanny. The first tier, involving IRT screening at 3 days of age, utilizes a low elevation of the trypsinogen level (600 ng/ml), which is highly sensitive. The second tier, which corresponds to the exhaustive screening for mutations in three exons of the gene, is highly specific for this population (Britanny). The false positive rate is very low, and no false negatives have been reported to date. This strategy has allowed the identification of five novel alleles (V322A, V317A, 1806 del A, R553G, G544S).

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82 {17bi DI507 [ Y569X W846X 2789+5G->A ,' $492F i ] i I G551D 2622+1 G->A Y1092X 1717-1 G->A E827X A1067T G542X 2183 AA->G R1066H R560K 2184 ins A 3320,ins 5 R553G R1070W 1806 del A & 4005+1G->A W1282X ] i "- Exons Fig.2 Distribution of the different mutations (except AF508) of the CFTR gene in Brittany Table 1 Mutations and genotypes in newborns Genotypes of newborns Number Sweat test AF508/AF508 7 + > 90 AF508/1806 del A 1 + > 90 R553G/G551D 1 Borderline (60) AF508/G551D 1 + > 90 AF508/R1070W 1 40 AF508/G542X 1 + > 90 AF508/G149R 1 45 Total 13 Mutations found in heterozygote newborns AF508 31 R560K 1 1078 del T 1 G544S l G542X 1 V317A 1 R347H 1 V322A 1 Total 38 gene. Login to comment

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

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

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

[hide] A cluster of cystic fibrosis mutations in exon 17b... J Med Genet. 1994 Sep;31(9):731-4. Mercier B, Lissens W, Novelli G, Kalaydjieva L, de Arce M, Kapranov N, Canki Klain N, Estivill X, Palacio A, Cashman S, et al.
A cluster of cystic fibrosis mutations in exon 17b of the CFTR gene: a site for rare mutations.
J Med Genet. 1994 Sep;31(9):731-4., [PMID:7529319]

Abstract [show]
Intensive screening has improved our understanding of the profile of mutations in the CFTR gene in which more than 400 mutations have been detected to date. In collaboration with several European laboratories we are involved in such analysis. We have identified 14 new mutations in exon 17b of CFTR, having analysed 780 CF chromosomes, and have compared the frequency of mutations in this exon with that of other regions of the CFTR gene. The results obtained indicate an accumulation of mutations, not only in regions encoding the two nucleotide binding folds, but also in those encoding transmembrane domains of the CFTR gene, in particular exon 17b.

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19 Most of these are missense mutations and as no functional test has been 732 Table 1 Mutations identified in exon 17b of the CFTR gene Mutation Nucleotide Modificationl Ethnic Rcferencesposition ongini (No) 3271-1 G--A 3272-1 G-A Belgian (1) 11F1052V 3286 T-G Belgian (1) 11HI054D 3292 CG French (1) 13G1061R 3313 G-C French (1) 113320 Dup 3320 Duplication of Breton (1) 6 CTATG R1066C 3328 CT French (1) 14 R1066L R1066H A1067T G1069R R1070Q 3359 del CT L1077P H1085R W1089X Y1092X M1IOIR 3329 3329 3331 3337 3341 G-T G-+A G-A G,A G--A 3359 3362 3386 3398 3408 3434 del CT T--C A-.G G-+A C +A T--G Spanish (5) French (1) Breton (1) Breton (1) Bulgarian (1) Bulgarian (3) Rumanian (1) Albanian (1) French (1) Italian (1) French (1) Spanish (1) French (4) Turkish (1I) * Bozon et al, personal communication. Login to comment

[hide] Sensitivity of single-strand conformation polymorp... Hum Mol Genet. 1994 May;3(5):801-7. Ravnik-Glavac M, Glavac D, Dean M
Sensitivity of single-strand conformation polymorphism and heteroduplex method for mutation detection in the cystic fibrosis gene.
Hum Mol Genet. 1994 May;3(5):801-7., [PMID:7521710]

Abstract [show]
The gene responsible for cystic fibrosis (CF) contains 27 coding exons and more than 300 independent mutations have been identified. An efficient and optimized strategy is required to identify additional mutations and/or to screen patient samples for the presence of known mutations. We have tested several different conditions for performing single-stranded conformation polymorphism (SSCP) analysis in order to determine the efficiency of the method and to identify the optimum conditions for mutation detection. Each exon and corresponding exon boundaries were amplified. A panel of 134 known CF mutations were used to test the efficiency of detection of mutations. The SSCP conditions were varied by altering the percentage and cross-linking of the acrylamide, employing MDE (an acrylamide substitute), and by adding sucrose and glycerol. The presence of heteroduplexes could be detected on most gels and in some cases contributed to the ability to distinguish certain mutations. Each analysis condition detected 75-98% of the mutations, and all of the mutations could be detected by at least one condition. Therefore, an optimized SSCP analysis can be used to efficiently screen for mutations in a large gene.

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121 1078delT (35), L327R (Ravnik-Glavac a al., unpublished), R334W (36), D36K (31), R347L (26), R347P (14), A349V (26), R352Q (30), 1221delCT (34); Exon 8: W401X (31), 1342-1G-C (25); Exon 9: G458V (37), 1525 -1G-A (38); Exon 10: S492F (34), Q493X (39), 1609delCA (40,17), deltaI507 (39,41), deltaF5O8 (3), 1717-1G-A (39,42); Exon 11: G542X (39), S549N, G551D, R553X (43), R553Q (44), A559T (43), R560K (Fine et al., pers. comm.), R560T (39); Exon 12: Y563N (39), 1833delT (Schwartz et al., pers. comm.), P574H (39), 1898 + 1G-C (31), 1898+3A-G (Ferrari et al., pers. comm.); Exon 13: G628R(G-C) (31), Q685X (Firec et al., pers. comm.), K716X (26), L719X (Dork etal., pers. comm.), 2522insC (15), 2556insAT (45), E827X (34); Exon 14a: E831X (Ffrec et al., pers. comm.), R851X (29), 2721delll (31), C866Y (Audrezet et al., pers. comm.); Exon 14b: 2789+5G-A (Highsmith et al., pers. comm.); Exon 15: 2907denT (21), 2991del32 (Dark and TQmmler, pers. comm.), G970R (31); Exon 16: S977P, 3100insA (D6rk et al., pers. comm.); Exon 17a: I1005R (Dork and TQmmler, pers. comm.), 3272-1G-A (46); Exon 17b: H1054D (F6rec et al., pers. comm.), G1061R (Fdrec et al., pers. comm.), 332Oins5, R1066H, A1067T (34), R1066L (Fe"rec etal., pers. comm.), R1070Q (46), E1104X (Zielenski el al., pers. comm.), 3359delCT (46), L1077P (Bozon « a/., pers. comm.), H1085R (46), Y1092X (Bozon etal., pers. comm.), W1098R, M1101K (Zielenski et al., pers. comm.); Exon 18: D1152H (Highsmith et al., pers. comm.); Exon 19:R1162X (36), 3659delC (39), 3662delA (25), 3667del4 (Chillon et al., pers. comm.), 3737ddA (35), 3821ddT (15), I1234V (35), S1235R (31), Q1238X (26), 3849G-A (25), 385O-3T-G (38); Exon20:3860ins31 (Chillon etal., pers. comm.), S1255X (47), 3898insC (26), 3905insT (Malik et al., pers. comm.), D127ON (48), W1282X (49), Q1291R (Dork et al., pers. comm.), Exon 21: N1303H (35), N13O3K (50), W1316X (43); Exon 22: 11328L/4116delA (Dork and TQmmler, pers. comm.), E1371X (25); Exon 23: 4374+ 1G-T (38); Exon 24: 4382delA (Claustres et al., pers. comm.). Login to comment

[hide] Analysis of the whole CFTR coding regions and spli... Hum Genet. 1994 Apr;93(4):467-70. Culard JF, Desgeorges M, Costa P, Laussel M, Razakatzara G, Navratil H, Demaille J, Claustres M
Analysis of the whole CFTR coding regions and splice junctions in azoospermic men with congenital bilateral aplasia of epididymis or vas deferens.
Hum Genet. 1994 Apr;93(4):467-70., [PMID:7513294]

Abstract [show]
Several recent studies have demonstrated the presence of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in healthy males with infertility caused by congenital absence of the vas deferens (CBAVD), previously recognized as an idiopathic genetic condition distinct from CF. In order to document further the genetic commonality of these two disorders, we undertook a double screening of the entire coding and flanking sequences of the CFTR gene, by using single-strand conformational polymorphism analysis and denaturing gradient gel electrophoresis in 12 unrelated infertile men with abnormalities of the vas deferens and/or epididymis. This strategy allowed us to identify 11 DNA sequence alterations considered as CF-causing mutations and several variations. Despite this double analysis, only two patients out of eight with CBAVD could be demonstrated as compound heterozygotes for CF mutations.

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27 The missense mutation A 1067T in exon 17b (Ferec et al. 1992) was identified in a CBAVD patient with AF508, but, interestingly, the familial study revealed that A1067T was located on the paternally inherited CF chromosome already bearing AF508. Login to comment
33 CFTR mutations identified in 12 patients lacking an epididymis or vas deferens Patient Age Mutations Exon XV2c/KM19 (years) haplotypesa CBAVD 1 43 Unknown B Unknown A CBAVD 6 33 p AF508/A1067T 10/17b B m Unknown A CBAVD 8 32 p Unknown A m AF508 10 B CBAVD 9 27 p R347H 7 C m AF508 10 B CBAVD 11 31 m Unknown D p 2184delA+A---~G at 2183 13 B CBAVD 12 30 Unknown B Unknown B CBAVD 13 32 p AF508 10 B m Unknown A CBAVD 14 AF508 10 B R347H 7 C CUAVD 4 35 m G542X 11 B p Unknown D CBAE 2 28 Unknown C Unknown D CBAE 7 34 p Unknown B m S1235R 19 A CBAE 10 30 Unknown B Unknown C CBAVD, Congenital bilateral aplasia of the vas deferens; CUAVD, congenital unilateral aplasia of the vas deferens; CBAE, congenital bilateral aplasia of the epididymis; p, paternal chromosome; m, maternal chromosome The four haplotypes defined by the CFTR-linked polymorphic restriction sites XV-2c and KM-19 are as follows: A, 1-1; B, -2; C, 2-1; D, 2-2 (the absence of the restriction site for each polymorphism is defined as allele "1", and the presence of the site as allele "2") Table . Login to comment

[hide] Analysis of the CFTR gene confirms the high geneti... Hum Genet. 1994 Apr;93(4):447-51. Chillon M, Casals T, Gimenez J, Ramos MD, Palacio A, Morral N, Estivill X, Nunes V
Analysis of the CFTR gene confirms the high genetic heterogeneity of the Spanish population: 43 mutations account for only 78% of CF chromosomes.
Hum Genet. 1994 Apr;93(4):447-51., [PMID:7513293]

Abstract [show]
We have analysed 972 unrelated Spanish cystic fibrosis patients for 70 known mutations. Analysis was performed on exons 1, 2, 3, 4, 5, 6a, 6b, 7, 10, 11, 12, 13, 14a, 14b, 15, 16, 17b, 18, 19, 20 and 21 of the cystic fibrosis transmembrane regulator gene using single strand conformation polymorphism analysis and denaturing gradient gel electrophoresis. The major mutation delta F508 accounts for 50.6% of CF chromosomes, whereas another 42 mutations account for 27.6% of CF chromosomes, with 21.8% of Spanish CF chromosomes remaining uncharacterized. At present, we have identified 36 mutations that have frequency of less than 1% and that are spread over 15 different exons. This indicates that, in the Spanish population, with the exception of delta F508 (50.6%) and G542X (8%), the mutations are not concentrated in a few exons of the gene nor are there any predominating mutations. This high degree of genetic heterogeneity is mainly a result of the different ethnic groups that have populated Spain and of the maintenance of separated population sets (Basques, Arab-Andalusian, Mediterranean, Canarian and Gallician). The high proportion of CF chromosomes still unidentified (21.8%) together with association analysis with intragenic markers suggest that at least 100 different mutations causing CF are present in our population.

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31 At present, we have not detected any Spanish CF chromosomes bearing any of the following mutations: 394delTA, Y122X, 556delA, 852de122, R347P, $492F, 1677delTA, V520F, Q552X, R553X, L559S, R560K, R560T, Y563N, P564H, 2043delG, 3320ins5, R1066H, A1067T, H1085R, 3732delA, 3737delA, I1234V, S1255P, 3898insC, Q1291H or 4005+ 1G---~A. Login to comment

[hide] Cystic fibrosis: the 'bicarbonate before chloride'... Curr Biol. 2001 Jun 26;11(12):R463-6. Wine JJ
Cystic fibrosis: the 'bicarbonate before chloride' hypothesis.
Curr Biol. 2001 Jun 26;11(12):R463-6., [PMID:11448786]

Abstract [show]
The specific effects of some mutations that cause cystic fibrosis suggest that reduced HCO(3)(-) transport is the key to understanding cystic fibrosis pathology. But there is a puzzling discrepancy between measures of CFTR-mediated chloride conductance in expression systems and the sweat chloride values of patients.

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52 Ion transport (% WT) 42 41 69 75 >100 >100 98 + 103 100 + + 120 Pancreatic sufficient Pancreatic insufficient Bicarbonate Chloride - intermediate Chloride - high Unknown WT D648V R117H R1070Q H949Y G551S H620Q I148T A1067T G178R G970R S1255P G1244E G551D G1349D 0 0.5 1 1.5 2 2.5 Current Biology ࢞F508 Dispatch R absence of the vas deferens [16]. Login to comment

[hide] Development of CFTR Structure. Front Pharmacol. 2012 Sep 6;3:162. doi: 10.3389/fphar.2012.00162. eCollection 2012. Patrick AE, Thomas PJ
Development of CFTR Structure.
Front Pharmacol. 2012 Sep 6;3:162. doi: 10.3389/fphar.2012.00162. eCollection 2012., [PMID:22973227]

Abstract [show]
Cystic fibrosis is a lethal genetic disease caused by lack of functional cystic fibrosis transmembrane conductance regulator (CFTR) proteins at the apical surface of secretory epithelia. CFTR is a multidomain protein, containing five domains, and its functional structure is attained in a hierarchical folding process. Most CF-causing mutations in CFTR, including the most common mutation, a deletion of phenylalanine at position 508 (DeltaF508), are unable to properly fold into this functional native three dimensional structure. Currently, no high-resolution structural information about full length CFTR exists. However, insight has been gained through examining homologous ABC transporter structures, molecular modeling, and high-resolution structures of individual, isolated CFTR domains. Taken together, these studies indicate that the prevalent DeltaF508 mutation disrupts two essential steps during the development of the native structure: folding of the first nucleotide binding domain (NBD1) and its later association with the fourth intracellular loop (ICL4) in the second transmembrane domain (TMD2). Therapeutics to rescue DeltaF508 and other mutants in CFTR can be targeted to correct defects that occur during the complex folding process. This article reviews the structural relationships between CFTR and ABC transporters and current knowledge about how CFTR attains its structure-with a focus on how this process is altered by CF-causing mutations in a manner targetable by therapeutics.

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155 For instance, in the NBD-ICL4 interface, mutants in ICL4 including L1065P, R1066C, and A1067T alter trafficking and chloride channel function (Cotten et al., 1996; Seibert et al., 1996). 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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44 None M1V A46D E56K P67L R74W G85E E92K D110E D110H R117C R117H E193K L206W R334W I336K T338I S341P R347H R347P R352Q A455E L467P S492F F508del V520F A559T R560S R560T A561E Y569D D579G R668C L927P S945L S977F L997F F1052V H1054D K1060T L1065P R1066C R1066H R1066M A1067T R1070Q R1070W F1074L L1077P H1085R M1101K D1152H S1235R D1270N N1303K 0 100 200 300 400 500 600 * * * CFTR Mutation mRNA (% Normal CFTR) Fig. 1. Login to comment
64 Mutant CFTR form CFTR processing Mature/total % Normal CFTR Normal 0.89 &#b1; 0.01 100.0 &#b1; 18.5 G85E -0.05 &#b1; 0.04 -1.0 &#b1; 0.9 R560S 0.00 &#b1; 0.00 0.0 &#b1; 0.0 R1066C 0.02 &#b1; 0.01 0.0 &#b1; 0.0 S492F 0.00 &#b1; 0.00 0.1 &#b1; 0.1 R560T 0.01 &#b1; 0.01 0.2 &#b1; 0.1 V520F 0.05 &#b1; 0.03 0.3 &#b1; 0.2 M1101K 0.05 &#b1; 0.03 0.3 &#b1; 0.1 A561E 0.08 &#b1; 0.04 0.5 &#b1; 0.2 R1066M 0.02 &#b1; 0.02 0.5 &#b1; 0.4 N1303K 0.02 &#b1; 0.02 0.5 &#b1; 0.3 A559T 0.16 &#b1; 0.09 0.6 &#b1; 0.2 M1V 0.06 &#b1; 0.06 0.7 &#b1; 0.6 Y569D 0.11 &#b1; 0.04 0.6 &#b1; 0.2 R1066H 0.08 &#b1; 0.02a 0.7 &#b1; 0.2a L1065P 0.05 &#b1; 0.05 1.0 &#b1; 0.8 L467P 0.10 &#b1; 0.07 1.2 &#b1; 0.8 L1077P 0.08 &#b1; 0.04 1.5 &#b1; 0.6 A46D 0.21 &#b1; 0.08 1.9 &#b1; 0.5a E92K 0.06 &#b1; 0.05 1.9 &#b1; 1.3 H1054D 0.09 &#b1; 0.04 1.9 &#b1; 0.8 F508del 0.09 &#b1; 0.02a 2.3 &#b1; 0.5a H1085R 0.06 &#b1; 0.01a 3.0 &#b1; 0.7a I336K 0.42 &#b1; 0.05a 6.5 &#b1; 0.7a L206W 0.35 &#b1; 0.10a 6.8 &#b1; 1.7a F1074L 0.52 &#b1; 0.03a 10.9 &#b1; 0.6a A455E 0.26 &#b1; 0.10a 11.5 &#b1; 2.5a E56K 0.29 &#b1; 0.04a 12.2 &#b1; 1.5a R347P 0.48 &#b1; 0.04a 14.6 &#b1; 1.8a R1070W 0.61 &#b1; 0.04a 16.3 &#b1; 0.6a P67L 0.36 &#b1; 0.04a 28.4 &#b1; 6.8a R1070Q 0.90 &#b1; 0.01a 29.5 &#b1; 1.4a S977F 0.97 &#b1; 0.01a 37.3 &#b1; 2.4a A1067T 0.78 &#b1; 0.03a 38.6 &#b1; 6.1a D579G 0.72 &#b1; 0.02a 39.3 &#b1; 3.1a D1270N 1.00 &#b1; 0.00a,c 40.7 &#b1; 1.2a S945L 0.65 &#b1; 0.04a 42.4 &#b1; 8.9a L927P 0.89 &#b1; 0.01a,b 43.5 &#b1; 2.5a,b R117C 0.87 &#b1; 0.02a,b 49.1 &#b1; 2.9a,b T338I 0.93 &#b1; 0.03a,b 54.2 &#b1; 3.7a,b L997F 0.90 &#b1; 0.04a,b 59.8 &#b1; 10.4a,b D110H 0.97 &#b1; 0.01a,b 60.6 &#b1; 1.5a,b S341P 0.79 &#b1; 0.02a 65.0 &#b1; 4.9a,b R668C 0.94 &#b1; 0.03a,b 68.5 &#b1; 1.9a,b R74W 0.78 &#b1; 0.01a 69.0 &#b1; 2.7a,b D110E 0.92 &#b1; 0.05a,b 87.5 &#b1; 9.5a,b R334W 0.91 &#b1; 0.05a,b 97.6 &#b1; 10.0a,b K1060T 0.87 &#b1; 0.02a,b 109.9 &#b1; 28.0a,b R347H 0.96 &#b1; 0.02a,c 120.7 &#b1; 2.8a,b S1235R 0.96 &#b1; 0.00a,c 139.0 &#b1; 9.0a,b E193K 0.84 &#b1; 0.02a,b 143.0 &#b1; 17.1a,b R117H 0.86 &#b1; 0.01a,b 164.5 &#b1; 34.2a,b R352Q 0.98 &#b1; 0.01a,b 179.9 &#b1; 8.0a,c F1052V 0.90 &#b1; 0.01a,b 189.9 &#b1; 33.1a,b D1152H 0.96 &#b1; 0.02a,c 312.0 &#b1; 45.5a,b Notes to Table 1: Quantification of steady-state CFTR maturation expressed as the mean (&#b1;SEM; n = 5-9) ratio of mature CFTR to total CFTR (immature plus mature) or level of mature mutant CFTR relative to mature normal-CFTR (% normal CFTR) in FRT cells individually expressing CFTR mutations. Login to comment
74 Because the level of CFTR mRNA was similar across the panel of cell lines tested, the range in baseline activity and ivacaftor response likely reflects the severity of the functional defect and/or the 0 50 100 150 200 S341P R347P L467P S492F A559T A561E Y569D L1065P R1066C R1066M L1077P M1101K N1303K R560S L927P R560T H1085R V520F E92K M1V F508del H1054D I336K A46D G85E R334W T338I R1066H R352Q R117C L206W R347H S977F S945L A455E F1074L E56K P67L R1070W D110H D579G D110E R1070Q L997F A1067T E193K R117H R74W K1060T R668C D1270N D1152H S1235R F1052V Baseline With ivacaftor * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Chloride transport (% Normal) Mutant CFTR form 0 100 200 300 400 S341P R347P L467P S492F A559T A561E Y569D L1065P R1066C R1066M L1077P M1101K N1303K R560S L927P R560T H1085R V520F E92K M1V F508del H1054D I336K A46D G85E R334W T338I R1066H R352Q R117C L206W R347H S977F S945L A455E F1074L P67L E56K R1070W D110H D579G D110E R1070Q L997F A1067T E193K R117H R74W K1060T R668C D1270N D1152H S1235R F1052V * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Mature CFTR (% Normal) Mutant CFTR form A B Fig. 2. Login to comment
82 Mutation Patientsa Chloride transport (bc;A/cm2 ) Chloride transport (% normal) EC50 Baseline With ivacaftor Baseline With ivacaftor Fold increase over baselineb Normal 204.5 &#b1; 33.3 301.3 &#b1; 33.8c 100.0 &#b1; 16.3 147.3 &#b1; 16.5c 1.5 266 &#b1; 42 G551D 1282 1.5 &#b1; 0.7 113.2 &#b1; 13.0c 1.0 &#b1; 0.5 55.3 &#b1; 6.3c 55.3 312 &#b1; 73 F1052V 12 177.3 &#b1; 13.7 410.2 &#b1; 11.3c 86.7 &#b1; 6.7 200.7 &#b1; 5.6c 2.3 177 &#b1; 14 S1235R ND 160.6 &#b1; 25.7 352.1 &#b1; 43.4c 78.5 &#b1; 12.6 172.2 &#b1; 21.2c 2.2 282 &#b1; 104 D1152H 185 117.3 &#b1; 23.0 282.7 &#b1; 46.9c 57.4 &#b1; 11.2 138.2 &#b1; 22.9c 2.4 178 &#b1; 67 D1270N 32 109.5 &#b1; 20.5 209.5 &#b1; 27.4c 53.6 &#b1; 10.0 102.4 &#b1; 13.4c 1.9 254 &#b1; 56 R668C 45 99.0 &#b1; 9.4 217.6 &#b1; 11.7c 48.4 &#b1; 4.6 106.4 &#b1; 5.7c 2.2 517 &#b1; 105 K1060T ND 89.0 &#b1; 9.8 236.4 &#b1; 20.3c 43.5 &#b1; 4.8 115.6 &#b1; 9.9c 2.7 131 &#b1; 73 R74W 25 86.8 &#b1; 26.9 199.1 &#b1; 16.8c 42.5 &#b1; 13.2 97.3 &#b1; 8.2c 2.3 162 &#b1; 17 R117H 739 67.2 &#b1; 13.3 274.1 &#b1; 32.2c 32.9 &#b1; 6.5 134.0 &#b1; 15.7c 4.1 151 &#b1; 14 E193K ND 62.2 &#b1; 9.8 379.1 &#b1; 1.1c 30.4 &#b1; 4.8 185.4 &#b1; 1.0c 6.1 240 &#b1; 20 A1067T ND 55.9 &#b1; 3.2 164.0 &#b1; 9.7c 27.3 &#b1; 1.6 80.2 &#b1; 4.7c 2.9 317 &#b1; 214 L997F 27 43.7 &#b1; 3.2 145.5 &#b1; 4.0c 21.4 &#b1; 1.6 71.2 &#b1; 2.0c 3.3 162 &#b1; 12 R1070Q 15 42.0 &#b1; 0.8 67.3 &#b1; 2.9c 20.6 &#b1; 0.4 32.9 &#b1; 1.4c 1.6 164 &#b1; 20 D110E ND 23.3 &#b1; 4.7 96.4 &#b1; 15.6c 11.4 &#b1; 2.3 47.1 &#b1; 7.6c 4.1 213 &#b1; 51 D579G 21 21.5 &#b1; 4.1 192.0 &#b1; 18.5c 10.5 &#b1; 2.0 93.9 &#b1; 9.0c 8.9 239 &#b1; 48 D110H 30 18.5 &#b1; 2.2 116.7 &#b1; 11.3c 9.1 &#b1; 1.1 57.1 &#b1; 5.5c 6.2 249 &#b1; 59 R1070W 13 16.6 &#b1; 2.6 102.1 &#b1; 3.1c 8.1 &#b1; 1.3 49.9 &#b1; 1.5c 6.2 158 &#b1; 48 P67L 53 16.0 &#b1; 6.7 88.7 &#b1; 15.7c 7.8 &#b1; 3.3 43.4 &#b1; 7.7c 5.6 195 &#b1; 40 E56K ND 15.8 &#b1; 3.1 63.6 &#b1; 4.4c 7.7 &#b1; 1.5 31.1 &#b1; 2.2c 4.0 123 &#b1; 33 F1074L ND 14.0 &#b1; 3.4 43.5 &#b1; 5.4c 6.9 &#b1; 1.6 21.3 &#b1; 2.6c 3.1 141 &#b1; 19 A455E 120 12.9 &#b1; 2.6 36.4 &#b1; 2.5c 6.3 &#b1; 1.2 17.8 &#b1; 1.2c 2.8 170 &#b1; 44 S945L 63 12.3 &#b1; 3.9 154.9 &#b1; 47.6c 6.0 &#b1; 1.9 75.8 &#b1; 23.3c 12.6 181 &#b1; 36 S977F 9 11.3 &#b1; 6.2 42.5 &#b1; 19.1c 5.5 &#b1; 3.0 20.8 &#b1; 9.3c 3.8 283 &#b1; 36 R347H 65 10.9 &#b1; 3.3 106.3 &#b1; 7.6c 5.3 &#b1; 1.6 52.0 &#b1; 3.7c 9.8 280 &#b1; 35 L206W 81 10.3 &#b1; 1.7 36.4 &#b1; 2.8c 5.0 &#b1; 0.8 17.8 &#b1; 1.4c 3.6 101 &#b1; 13 R117C 61 5.8 &#b1; 1.5 33.7 &#b1; 7.8c 2.9 &#b1; 0.7 16.5 &#b1; 3.8c 5.7 380 &#b1; 136 R352Q 46 5.5 &#b1; 1.0 84.5 &#b1; 7.8c 2.7 &#b1; 0.5 41.3 &#b1; 3.8c 15.2 287 &#b1; 75 R1066H 29 3.0 &#b1; 0.3 8.0 &#b1; 0.8c 1.5 &#b1; 0.1 3.9 &#b1; 0.4c 2.6 390 &#b1; 179 T338I 54 2.9 &#b1; 0.8 16.1 &#b1; 2.4c 1.4 &#b1; 0.4 7.9 &#b1; 1.2c 5.6 334 &#b1; 38 R334W 150 2.6 &#b1; 0.5 10.0 &#b1; 1.4c 1.3 &#b1; 0.2 4.9 &#b1; 0.7c 3.8 259 &#b1; 103 G85E 262 1.6 &#b1; 1.0 1.5 &#b1; 1.2 0.8 &#b1; 0.5 0.7 &#b1; 0.6 NS NS A46D ND 2.0 &#b1; 0.6 1.1 &#b1; 1.1 1.0 &#b1; 0.3 0.5 &#b1; 0.6 NS NS I336K 29 1.8 &#b1; 0.2 7.4 &#b1; 0.1c 0.9 &#b1; 0.1 3.6 &#b1; 0.1c 4 735 &#b1; 204 H1054D ND 1.7 &#b1; 0.3 8.7 &#b1; 0.3c 0.8 &#b1; 0.1 4.2 &#b1; 0.1c 5.3 187 &#b1; 20 F508del 29,018 0.8 &#b1; 0.6 12.1 &#b1; 1.7c 0.4 &#b1; 0.3 5.9 &#b1; 0.8c 14.8 129 &#b1; 38 M1V 9 0.7 &#b1; 1.4 6.5 &#b1; 1.9c 0.4 &#b1; 0.7 3.2 &#b1; 0.9c 8.0 183 &#b1; 85 E92K 14 0.6 &#b1; 0.2 4.3 &#b1; 0.8c 0.3 &#b1; 0.1 2.1 &#b1; 0.4c 7.0 198 &#b1; 46 V520F 58 0.4 &#b1; 0.2 0.5 &#b1; 0.2 0.2 &#b1; 0.1 0.2 &#b1; 0.1 NS NS H1085R ND 0.3 &#b1; 0.2 2.1 &#b1; 0.4 0.2 &#b1; 0.1 1.0 &#b1; 0.2 NS NS R560T 180 0.3 &#b1; 0.3 0.5 &#b1; 0.5 0.1 &#b1; 0.1 0.2 &#b1; 0.2 NS NS L927P 15 0.2 &#b1; 0.1 10.7 &#b1; 1.7c 0.1 &#b1; 0.1 5.2 &#b1; 0.8c 52.0 313 &#b1; 66 R560S ND 0.0 &#b1; 0.1 -0.2 &#b1; 0.2 0.0 &#b1; 0.0 -0.1 &#b1; 0.1 NS NS N1303K 1161 0.0 &#b1; 0.0 1.7 &#b1; 0.3 0.0 &#b1; 0.0 0.8 &#b1; 0.2 NS NS M1101K 79 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS L1077P 42 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R1066M ND 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R1066C 100 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS L1065P 25 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS Y569D 9 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS A561E ND 0.0 &#b1; 0.1 0.0 &#b1; 0.1 0.0 &#b1; 0.0 0.0 &#b1; 0.1 NS NS A559T 43 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS S492F 16 0.0 &#b1; 0.0 1.7 &#b1; 1.2 0.0 &#b1; 0.0 0.8 &#b1; 0.6 NS NS L467P 16 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R347P 214 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS S341P 9 0.0 &#b1; 0.0 0.2 &#b1; 0.2 0.0 &#b1; 0.0 0.1 &#b1; 0.1 NS NS a Number of individuals with the individual mutation in the CFTR-2 database (www.CFTR2.org). Login to comment
86 For example, the baseline level of chloride transport and ivacaftor response was higher for mutant CFTR forms associated with mild defects in CFTR processing (e.g., E56K, P67L, L206W, A455E, D579G, S945L, S977F, A1067T, R1070Q, R1070W, F1074L, and D1270N) than for those associated with severe defects in CFTR processing (e.g., F508del, H1054D, R1066H). Login to comment
89 For mutant CFTR forms that have multiple defects (e.g., R117H, F508del, S945L, R1070Q, A1067T, R1070W, and R347P), the relative impact of each defect is likely to affect the magnitude of the baseline chloride transport and ivacaftor response in vitro and in a clinical setting. Login to comment
92 Mutant CFTR forms that did not significantly respond to ivacaftor under the experimental conditions used in this study were generally associated with severe defects in CFTR processing A B C D E F 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 S1235R D1152H F1052V D1270N ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 R668C K1060T R74W R117H ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 E193K A1067T L997F R1070Q ivacaftor [Log M] Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 D110E D579G D110H R1070W ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 F1074L E56K P67L A455E ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 R347H S945L L206W S977F ivacaftor [Log M] 0 100 200 300 400 -8 -6 -4 0 T338I R1066H R117C R352Q ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 F508del R334W H1054D E92K ivacaftor [Log M] 0 5 10 15 20 -9 -8 -7 -6 -5 -4 0 F508del R334W H1054D E92K R1066H T338I ivacaftor [Log M] G H I Fig. 3. Login to comment

[hide] Understanding how cystic fibrosis mutations disrup... Int J Biochem Cell Biol. 2014 Jul;52:47-57. doi: 10.1016/j.biocel.2014.04.001. Epub 2014 Apr 13. Wang Y, Wrennall JA, Cai Z, Li H, Sheppard DN
Understanding how cystic fibrosis mutations disrupt CFTR function: from single molecules to animal models.
Int J Biochem Cell Biol. 2014 Jul;52:47-57. doi: 10.1016/j.biocel.2014.04.001. Epub 2014 Apr 13., [PMID:24727426]

Abstract [show]
Defective epithelial ion transport is the hallmark of the life-limiting genetic disease cystic fibrosis (CF). This abnormality is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), the ATP-binding cassette transporter that functions as a ligand-gated anion channel. Since the identification of the CFTR gene, almost 2000 disease-causing mutations associated with a spectrum of clinical phenotypes have been reported, but the majority remain poorly characterised. Studies of a small number of mutations including the most common, F508del-CFTR, have identified six general mechanisms of CFTR dysfunction. Here, we review selectively progress to understand how CF mutations disrupt CFTR processing, stability and function. We explore CFTR structure and function to explain the molecular mechanisms of CFTR dysfunction and highlight new knowledge of disease pathophysiology emerging from large animal models of CF. Understanding CFTR dysfunction is crucial to the development of transformational therapies for CF patients.

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1987 Encouragingly, the data suggest that ivacaftor potentiates multiple gating mutants located in different parts of CFTR structure including R117H (M2), R668C (RD) and A1067T (ICL4) (Yu et al., 2012; Van Goor et al., 2014). Login to comment