ABCC7 p.Val520Ile
| ClinVar: |
c.1558G>A
,
p.Val520Ile
?
, Conflicting interpretations of pathogenicity, not provided
c.1558G>T , p.Val520Phe D , Pathogenic |
| CF databases: |
c.1558G>T
,
p.Val520Phe
D
, CF-causing ; CFTR1: Using the chemical cleavage technique and direct sequencing, a G to T transversion has been demonstrated, changing a valine residue to phenylalanine. Although not a strongly conserved residue, we believe that the substitution of an aromatic for an alpiphatic amino-acid may be of consequence. V520F has been found on 2 out of 26 CF chromosomes with unknown mutations. In both cases on the B haplotype.
c.1558G>A , p.Val520Ile (CFTR1) ? , This mutation , in exon 10 of the CFTR gene, was detected by direct DNA sequencing and is a single base substitution from a guanine to an adenine at base 1690 of exon 10 of the CFTR gene. This results in the replacement of a Valine residue by an isoleucine in codon 520. The patient is a 7 year old boy from India and has an as yet unknown mutation on his other CF chromosome. We have seen this mutation once in 20 non-[delta]F508 CF chromosomes analysed by direct sequencing. |
| Predicted by SNAP2: | A: D (71%), C: D (80%), D: D (95%), E: D (95%), F: D (53%), G: D (95%), H: D (95%), I: D (66%), K: D (95%), L: D (95%), M: D (95%), N: D (95%), P: D (95%), Q: D (95%), R: D (95%), S: D (95%), T: D (91%), W: D (95%), Y: D (95%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: N, K: D, L: N, M: N, N: D, P: D, Q: D, R: D, S: D, T: N, W: D, Y: D, |
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[hide] Variant cystic fibrosis phenotypes in the absence ... N Engl J Med. 2002 Aug 8;347(6):401-7. Groman JD, Meyer ME, Wilmott RW, Zeitlin PL, Cutting GR
Variant cystic fibrosis phenotypes in the absence of CFTR mutations.
N Engl J Med. 2002 Aug 8;347(6):401-7., 2002-08-08 [PMID:12167682]
Abstract [show]
BACKGROUND: Cystic fibrosis is a life-limiting autosomal recessive disorder with a highly variable clinical presentation. The classic form involves characteristic findings in the respiratory tract, gastrointestinal tract, male reproductive tract, and sweat glands and is caused by loss-of-function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR ) gene. Nonclassic forms of cystic fibrosis have been associated with mutations that reduce but do not eliminate the function of the CFTR protein. We assessed whether alteration in CFTR function is responsible for the entire spectrum of variant cystic fibrosis phenotypes. METHODS: Extensive genetic analysis of the CFTR gene was performed in 74 patients with nonclassic cystic fibrosis who had been referred by 34 medical centers. We evaluated two families that each included a proband without identified mutations and a sibling with nonclassic cystic fibrosis to determine whether there was linkage to the CFTR locus and to measure the extent of CFTR function in the sweat gland and nasal epithelium. RESULTS: Of the 74 patients studied, 29 had two mutations in the CFTR gene, 15 had one mutation, and 30 had no mutations. A final genotype of two mutations was more common among patients who had been referred after screening for common cystic fibrosis-causing mutations identified one mutation than among those who had been referred after screening had identified no such mutations (26 of 34 patients vs. 3 of 40 patients, P<0.001). Comparison of clinical features and sweat chloride concentrations revealed no significant differences among patients with two, one, or no CFTR mutations. Haplotype analysis in the two families revealed no linkage to CFTR. Although each of the affected siblings had elevated sweat chloride concentrations, measurements of cyclic AMP-mediated ion and fluid transport in the sweat gland and nasal epithelium demonstrated the presence of functional CFTR. CONCLUSIONS: Factors other than mutations in the CFTR gene can produce phenotypes clinically indistinguishable from nonclassic cystic fibrosis caused by CFTR dysfunction.
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71 MUTATION IDENTIFIED BY SCREENING FOR COMMON MUTATIONS MUTATION IDENTIFIED BY DNA SEQUENCING NO. OF PATIENTS ∆F508 5T* 3 ∆F508 D1152H 2 ∆F508 2789+2insA 2 ∆F508 R117C 2 ∆F508 D110H 1 ∆F508 2789+5G→A 1 ∆F508 P205S 1 ∆F508 L967S 1 ∆F508 I1027T 1 ∆F508 L206W 1 ∆F508 T1053I and 5T 1 ∆F508 V920M and 5T 1 ∆F508 R1070W 1 ∆F508 D579G 1 ∆F508 P67L 1 ∆F508 2811G→T†‡ 1 G85E F191V† 1 R117H G103X and 5T 1 I148T I556V 1 G542X R1162L 1 W1282X D1152H 1 None L138ins and 3272-26 A→G 1 None G463D† and 5T 1 None F693L and 5T 1 ∆F508 None 6 G551D None 1 W1282X None 1 None 5T 4 None 2307insA 1 None L997F 1 None V520I 1 None None 30 in Subject II-2 in Family 1.
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ABCC7 p.Val520Ile 12167682:71:764
status: NEW[hide] Improved detection of cystic fibrosis mutations in... Hum Reprod. 2004 Mar;19(3):540-6. Epub 2004 Jan 29. Danziger KL, Black LD, Keiles SB, Kammesheidt A, Turek PJ
Improved detection of cystic fibrosis mutations in infertility patients with DNA sequence analysis.
Hum Reprod. 2004 Mar;19(3):540-6. Epub 2004 Jan 29., [PMID:14998948]
Abstract [show]
BACKGROUND: Accurate determination of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is critical for genetic counselling and treatment of obstructive azoospermia. Of concern is that detection rates with routine CFTR mutation panels vary widely depending on patient ancestry; and such panels have limited value for azoospermic patients, who are more likely to carry rare mutations. An alternative approach offers comprehensive, CFTR mutation analysis by a DNA sequence method. We investigated whether this method could improve CFTR detection rates in men with obstructive azoospermia in a prospective study of men with obstructive azoospermia and their partners who were referred for genetic counselling and testing at one of two institutions. METHODS: Sixteen patients with congenital absence of the vas deferens (CAVD, n = 14) or idiopathic obstructive azoospermia (n = 2) were studied. DNA from all patients was analysed for mutations by the DNA sequence method. In addition to this method, six men underwent CFTR analysis by a common 25 or 31 mutation panel coupled with poly T analysis. In 10 subjects, common mutation panel findings were inferred from DNA sequence method results. RESULTS: Overall, 12/16 (75%) azoospermic patients had one or more CFTR mutations and/or 5T alleles, including 12 mutations in 10 patients (two compound heterozygotes) and seven 5T alleles in six patients (one homozygote). The sequence method detected all mutations and three variants of unknown significance. By comparison, the common mutation panels detected only 3/12 mutations (25%) and 0/3 variants. CONCLUSION: The DNA sequence method detects more CFTR mutations than common mutation panels. Given the serious, clinical consequences of transmitting such mutations, this study underscores the importance of accurate, CFTR mutation detection in men with obstructive azoospermia and their partners.
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84 Diagnosis/clinical information Ancestry 5T allele Common mutation panel Sequence method Interpretation Mutation panel/ DNA sequence concordance 1 CBAVD N.E. Cauc. Negative Negative Het. P750L Mutation No 2 CBAVD Asian Het. Negative Negative No mutation detected Yes 3 CBAVD Asian Negative Negative Het. V201M Mutation No 4 CBAVD Asian-Indian Het. Negative Het. 1717±4A®G Variant of unknown signi®cance No 5 CBAVD Asian Negative * V520I/3601±3C®A Mutation/variant of unknown signi®cance Nod 6 CBAVDa N.E./S.E.
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ABCC7 p.Val520Ile 14998948:84:445
status: NEW121 Mutations and variants of unknown signi®cance detected in 16 patients with CAVD Detection method 31 common mutation panel and poly T analysis Sequence method and poly T analysis Mutations 5T 7 7 DF508 2 2 R117H 1 1 P750L ± 1 V201M ± 1 Q1352H ± 1 I556V ± 1 2752±26A®G ± 1 W1098C ± 1 I807M ± 1 V456A ± 1 V520I ± 1 Variants of unknown signi®cance 1717±4A®G ± 1 3601±3C®A ± 1 3499+25C®G ± 1 Total 10 22 the vas deferens is particularly susceptible to the decreased levels of CFTR protein product.
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ABCC7 p.Val520Ile 14998948:121:357
status: NEW[hide] A frequent large rearrangement in the CFTR gene in... Genet Test. 2006 Fall;10(3):208-14. Nectoux J, Audrezet MP, Viel M, Leroy C, Raguenes O, Ferec C, Lesure JF, Davy N, Renouil M, Cartault F, Bienvenu T
A frequent large rearrangement in the CFTR gene in cystic fibrosis patients from Reunion Island.
Genet Test. 2006 Fall;10(3):208-14., [PMID:17020473]
Abstract [show]
Reunion Island is a French province, 800 km east of Madagascar and 200 km west of Mauritius. On Reunion Island, the birth prevalence of cystic fibrosis (CF) is particularly high in the population of European origin, approximately 1:1000. In a previous study, we demonstrated that the screening of the 27 exons of the CF transmembrane conductance regulator (CFTR) gene by denaturing high-pressure liquid chromatography (DHPLC) in 114 CF families allowed the detection of about 93% of the molecular defects present on Reunion Island. Unidentified CF mutations may lie in introns or in regulatory regions that are not routinely investigated, or may correspond to gene rearrangements such as large, heterozygous deletions that escape detection using current PCR-based techniques. Using a combination of different methods (such as multiplex ligation-dependent probe amplification), 6 of the 13 unidentified CF alleles (46%) were found to harbor a deletion of 5288 bp, spanning from exon 17a to 18. Identification and examination of the breakpoint sequences showed that this deletion is different from the 3120+1kbdel8.6Kb previously found in the Palestinian Arabs. The chromosomes bearing IVS16+3316_IVS18+644del5288 did not have a common extragenic haplotype. Clinical evaluation of homozygotes (2 unrelated patients) and compound heterozygotes indicated that this deletion represents a severe mutation associated with positive sweat chloride test, pancreatic insufficiency, and early age at diagnosis.
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52 GENOTYPE OF CF PATIENTS FROM REUNION ISLAND WHO WERE FOUND TO CARRY AT LEAST ONE CFTR MUTATION-NEGATIVE ALLELE Present Patient Sex age (years) Cl-test Genotype Phenotype MUC971 F 6 87-91 p.V520I : unidentified PS-CF (bronchitis, mild disease) MUC696 M 10 37-70 c.3849 ϩ 45G l A : unidentified PS-CF (bronchitis) R105C F 82 56-106 p.A309G : unidentified PS-CF (H. influenzae colonization, bronchitis) MUC900 M 7 71-147 p.F508del : unidentified PI-CF R131C F 16 39-70 p.F508del : unidentified PS-CF (B. cepacia colonization, bronchitis) R89C F 20 23-107 p.F508del : unidentified PS-CF R71C F 17 58-90 p.G542X : unidentified PI-CF (S. aureus and P. aeruginosa colonization) R48C F 19 81 Unidentified : unidentified PI-CF (meconium ileus) R44C F 11 70 Unidentified : unidentified PI-CF (died at the age of 11 years) MUC74 M 6 125 Unidentified : unidentified PI-CF (bronchitis, mild disease) PS, pancreatic sufficiency; PI, pancreatic insufficiency; H, Haemophilus; B, Burkholderia; P, Pseudomonas; S, Staphylococcus.
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ABCC7 p.Val520Ile 17020473:52:189
status: NEW[hide] Impact of heterozygote CFTR mutations in COPD pati... Respir Res. 2014 Feb 11;15:18. doi: 10.1186/1465-9921-15-18. Raju SV, Tate JH, Peacock SK, Fang P, Oster RA, Dransfield MT, Rowe SM
Impact of heterozygote CFTR mutations in COPD patients with chronic bronchitis.
Respir Res. 2014 Feb 11;15:18. doi: 10.1186/1465-9921-15-18., [PMID:24517344]
Abstract [show]
BACKGROUND: Cigarette smoking causes Chronic Obstructive Pulmonary Disease (COPD), the 3rd leading cause of death in the U.S. CFTR ion transport dysfunction has been implicated in COPD pathogenesis, and is associated with chronic bronchitis. However, susceptibility to smoke induced lung injury is variable and the underlying genetic contributors remain unclear. We hypothesized that presence of CFTR mutation heterozygosity may alter susceptibility to cigarette smoke induced CFTR dysfunction. Consequently, COPD patients with chronic bronchitis may have a higher rate of CFTR mutations compared to the general population. METHODS: Primary human bronchial epithelial cells derived from F508del CFTR heterozygotes and mice with (CFTR+/-) and without (CFTR+/+) CFTR heterozygosity were exposed to whole cigarette smoke (WCS); CFTR-dependent ion transport was assessed by Ussing chamber electrophysiology and nasal potential difference measurements, respectively. Caucasians with COPD and chronic bronchitis, age 40 to 80 with FEV1/FVC < 0.70 and FEV1 < 60% predicted, were selected for genetic analysis from participants in the NIH COPD Clinical Research Network's Azithromycin for Prevention of Exacerbations of COPD in comparison to 32,900 Caucasian women who underwent prenatal genetic testing. Genetic analysis involved an allele-specific genotyping of 89 CFTR mutations. RESULTS: Exposure to WCS caused a pronounced reduction in CFTR activity in both CFTR (+/+) cells and F508del CFTR (+/-) cells; however, neither the degree of decrement (44.7% wild-type vs. 53.5% F508del heterozygous, P = NS) nor the residual CFTR activity were altered by CFTR heterozygosity. Similarly, WCS caused a marked reduction in CFTR activity measured by NPD in both wild type and CFTR heterozygous mice, but the severity of decrement (91.1% wild type vs. 47.7% CF heterozygous, P = NS) and the residual activity were not significantly affected by CFTR genetic status. Five of 127 (3.9%) COPD patients with chronic bronchitis were heterozygous for CFTR mutations which was not significantly different from controls (4.5%) (P = NS). CONCLUSIONS: The magnitude of WCS induced reductions in CFTR activity was not affected by the presence of CFTR mutation heterozygosity. CFTR mutations do not increase the risk of COPD with chronic bronchitis. CFTR dysfunction due to smoking is primarily an acquired phenomenon and is not affected by the presence of congenital CFTR mutations.
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81 As expected based on genotype-phenotype correlations in the disease [33], HBE cells derived from a F508del CFTR heterozygote had slightly lower CFTR activity at baseline than wild type monolayers as measured by Table 1 List of CFTR mutations analyzed F508del R117H 1717-1G > A R117C G85E R334W 1898 + 1G > A Y122X A455E R347P 2184delA G178R I507del R553X 2789 + 5G > A G314E G542X R560T 3120 + 1G > A G330X G551D W1282X 3659delC R347H N1303K 621 + 1G > T K710X 406-1G > A R1162X 711 + 1G > T E60X G480C R1066C W1089X V520F A559T S1196X Q1238X S1251N S1255X 663delT 935delA 1161delC 1288insTA 2184insA 2307insA 2711delT 2869insG R709X R764X R1158X 574delA Q493X 1898 + 5G > T 3905insT I506T 3849 + 10kbC > T 712-1G > T Q98R Q552X S549N 1078delT H199Y 444delA S549R (T > G) 2143delT P205S 2043delG 1811 + 1.6kbA > G 3272-26A > G L206W 3791delC Y1092X (C > G) 3199del6 F508C 2108delA Y1092X (C > A) D1152H V520I 3667del4 394delTT 3876delA M1101K 1677delTA W1098X (TGA) 1812-1G > A 4016insT 1609delCA 3171delC response to forskolin stimulation (49.3 &#b1; 11.5 bc;A/cm2 in CFTR (+/+) vs. 40.5 &#b1; 5.3 bc;A/cm2 in CFTR (+/-), although this was not statistically significant (Figure 1A,B).
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ABCC7 p.Val520Ile 24517344:81:903
status: NEW