ABCMdb

ABCC7 p.Glu60Lys

ClinVar:	c.178G>T , p.Glu60* D , Pathogenic
CF databases:	c.178G>T , p.Glu60* D , CF-causing c.178G>A , p.Glu60Lys (CFTR1) ? , This mutation was found by DGGE and direct DNA sequencing in a CF child who carries the DI507 in paternal CF chromosome. The patient is 5 years old, PS and sweat test 80mEq/l. Her healthy sister carries the DI507 mutation.(Original Note - Casals et al., 2August2000) The mutation was also reported by Claustres et al., 16November2000 This putative mutation was also detected by DGGE and identified by DNA fluorescent sequencing in an young CF patient from Southern France. She carries the mutation 2790-1G->C on the other chromosome.
Predicted by SNAP2:	A: D (63%), C: D (63%), D: D (66%), F: D (71%), G: D (75%), H: D (71%), I: D (75%), K: D (80%), L: D (75%), M: D (71%), N: D (71%), P: D (85%), Q: D (66%), R: D (80%), S: D (71%), T: D (71%), V: D (71%), W: D (75%), Y: D (63%),
Predicted by PROVEAN:	A: D, C: D, D: N, F: D, G: D, H: D, I: D, K: N, L: D, M: D, N: D, P: D, Q: N, R: D, S: D, T: D, V: D, W: D, Y: D,

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[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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116 Moreover, some nascent/immature CFTR protein present in the ER and A B 501 E92K Y89C G85E/V P5L S50P E60K R75Q NBD1 NBD2 R FIGURE 1. Login to comment
156 Confocal images from representative xy sections taken from1of 3 independent experiments show the subcellular distribution of wild-type CFTR (WT), p.F508del mutant (F508del), and variants p.S50P (S50P), p.E60K (E60K), p.G85E (G85E), p.G85V (G85V), p.E92K (E92K), p.P5L (P5L), p.R75Q (R75Q), and p.Y89C (Y89C). Login to comment
180 B: Recordings fromvariants p.S50P (S50P), p.E60K (E60K), p.G85E (G85E), p.G85V (G85V), and p.E92K (E92K) (superimposed recordings). Login to comment
3 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). Login to comment
4 Immunoblot analysis revealed that p.S50P, p.E60K, p.G85E/V, and p.E92K produced only core-glycosylated proteins. Login to comment
102 RESULTS Description and Cross-Species Analysis of Natural N-Terminus CFTR Variants We chose eight naturally occurring sequence variants, four located across the N-terminal CFTR tail (p.P5L, p.S50P, p.E60K, and p.R75Q), and four within the first segment of MSD1 (p.G85E, p.G85V, p.Y89C, and p.E92 K) (Fig. 1A; Table 1). Login to comment
110 In contrast, variants p.S50P, p.E60K, p.G85E, p.G85V, and p.E92K, produced only higher mobility band B proteins suggesting that, like the p.F508del mutant, the resulting misfolded channels are retained and degraded in the cytoplasm (Fig. 2A). Login to comment
118 B: Alignment of the N-terminus (amino acids 1 to 100) of the CFTR protein derived from di¡erent species.The sequences derived from human (Homo sapiens, Gen- BankNM_000492), mouse (Mus musculus,GenBankNM_021050), Norway rat (Rattusnovergicus,GenBankNM_031506), European rabbit (Oryctolagus cuniculus, GenBank NM_001082716), cow (Bos taurus, GenBank NM_174018), sheep (Ovis aries, GenBank NM_001009781), African clawed frog (Xenopus laevis, GenBank X65256), and spiny dog'sh (Squalus acanthias, GenBank M83785) were aligned using the ClustalW multiple sequence alignment program.The amino acid residue a¡ected by each of the variants analyzed (p.P5L, p.S50P, p.E60K, p.R75Q, p.G85E, p.G85V, p.Y89C, and p.E92K) is indicated in bold. Login to comment
122 Similarly, variants p.S50P, p.E60K, p.G85V, p.G85E, and p.E92K displayed a yellow colocalization pattern clearly compatible with retention of the anomalous CFTR proteins within the intracellular compartments and no detection of PM staining (Fig. 3). Login to comment
130 Likewise, none of the five variants (p.S50P, p.E60K, p.G85E, p.G85V, and p.E92K) in which severe misprocessing was previously demonstrated (Figs. 2 and 3), was able to generate cAMP-activated currents (Fig. 4B). Login to comment
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
215 Accordingly, using three different approaches (immunoblotting, immunocytochemistry, and electrophysiology) we found that 5 (p.S50P, p.E60K, p.G85E, p.G85V, and p.E92K) out of the 8 variants failed to mature, showing an analogous behavior than the most common F508del mutation. Login to comment
236 Thus, all these important interactions might be perturbed by the N-tail CFTR folding mutations p.S50P and p.E60K. Login to comment
238 Conversely, p.E60K results in an amino acid of opposite charge. Login to comment
245 Indeed, similarly to the above-referred cytosolic N-terminal CFTR variants p.S50P and p.E60K, folding and/or trafficking/processing defects seem to be the major factors contributing to the abnormal p.P5L CFTR phenotype, which showed a greatly reduced expression at the PM by immunodetection. Login to comment

[hide] Deletion of CFTR translation start site reveals fu... Cell Physiol Biochem. 2009;24(5-6):335-46. Epub 2009 Nov 4. Ramalho AS, Lewandowska MA, Farinha CM, Mendes F, Goncalves J, Barreto C, Harris A, Amaral MD
Deletion of CFTR translation start site reveals functional isoforms of the protein in CF patients.
Cell Physiol Biochem. 2009;24(5-6):335-46. Epub 2009 Nov 4., [PMID:19910674]

Abstract [show]
BACKGROUND/AIMS: Mutations in the CFTR gene cause Cystic Fibrosis (CF) the most common life-threatening autosomal recessive disease affecting Caucasians. We identified a CFTR mutation (c.120del23) abolishing the normal translation initiation codon, which occurs in two Portuguese CF patients. This study aims at functionally characterizing the effect of this novel mutation. METHODS: RNA and protein techniques were applied to both native tissues from CF patients and recombinant cells expressing CFTR constructs to determine whether c.120del23 allows CFTR protein production through usage of alternative internal codons, and to characterize the putative truncated CFTR form(s). RESULTS: Our data show that two shorter forms of CFTR protein are produced when the initiation translation codon is deleted indicating usage of internal initiation codons. The N-truncated CFTR generated by this mutation has decreased stability, very low processing efficiency, and drastically reduced function. Analysis of mutants of four methionine codons downstream to M1 (M82, M150, M152, M156) revealed that each of the codons M150/M152/M156 (exon 4) can mediate CFTR alternative translation. CONCLUSIONS: The CFTR N-terminus has an important role in avoiding CFTR turnover and in rendering effective its plasma membrane traffic. These data correlate well with the severe clinical phenotype of CF patients bearing the c.120del23 mutation.

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172 Altogether, these results for c.120del23-CFTR suggest an important role of the N-terminus in CFTR folding, stability and processing, which was also evidenced by other studies demonstrating that point mutations in this region - S50P; E60K; G85E/V; E92K - prevent CFTR maturation [35, 36]. 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

[hide] Estimating the age of CFTR mutations predominantly... J Cyst Fibros. 2008 Mar;7(2):168-73. Epub 2007 Sep 6. Fichou Y, Genin E, Le Marechal C, Audrezet MP, Scotet V, Ferec C
Estimating the age of CFTR mutations predominantly found in Brittany (Western France).
J Cyst Fibros. 2008 Mar;7(2):168-73. Epub 2007 Sep 6., [PMID:17825628]

Abstract [show]
BACKGROUND: Disparities in the spectrum of mutations within the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene are commonly observed in populations from different ethnical and/or geographical origins. The occurrence of CF in Brittany (western France) is one of the highest in populations from Caucasian origin (<1/2000 in specific areas). The W846X(2), 1078delT and G551D mutations, as well as the I1027T polymorphism in cis with the DeltaF508 mutation (currently referred to as p.F508del) are particularly frequent in this area. We investigated the age of the respective variants in the region of interest. METHODS: Several polymorphic markers surrounding the CFTR gene were genotyped. Allele frequencies as well as mutation rates and other parameters were used to calculate the respective age of the most recent common ancestors in the region of interest by a previously employed, simple likelihood-based method. RESULTS: Following haplotype reconstruction and simulation, the ages were estimated to be approximately 600, 1000, 1200 and 600 years, respectively (with a 95% confidence interval). CONCLUSIONS: These datings thus provide historical insights in the context of understanding population migrations. They also underline the usefulness of this method for estimating the age of rare mutations with a limited number of carriers.

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51 Primers amplifying the regions of interest were designed with PrimerQuestSM from Table 1 Genotypes of CF patients W846X2 1078delT G551D Mutation in trans Number Mutation in trans Number Mutation in trans Number ΔF508 6 ΔF508 21 ΔF508 18 R117C 1 1078delTa 2 E60K 1 ΔI507 1 4005+1GNA 2 W79X 1 Y563N 1 L610S 1 C225X 1 1078delTb 1 W846X2 b 1 F311L 1 621+1GNT 1 R1066H 1 R347H 1 2789+5GNA 1 1221delCT 1 G542X 1 3849+4ANG 1 1717-1GNA 1 G551D 1 3659delC 1 R553G 1 S942F 1 Y1092X 1 621+1GNT 1 2789+5GNA 1 4006-1GNA 1 Unidentified 1 Total 13 Total 31 Total 32 a One particular case: in this individual, the two chromosomes 7 are identical by descent. Login to comment