PMID: 15744523

Clain J, Lehmann-Che J, Girodon E, Lipecka J, Edelman A, Goossens M, Fanen P
A neutral variant involved in a complex CFTR allele contributes to a severe cystic fibrosis phenotype.
Hum Genet. 2005 May;116(6):454-60. Epub 2005 Mar 3., [PubMed]
Sentences
No. Mutations Sentence Comment
0 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:0:629
status: NEW
view ABCC7 p.Ser912Leu details
ORIGINAL INVESTIGATION Je´ roˆ me Clain Æ Jacqueline Lehmann-Che Emmanuelle Girodon Æ Joanna Lipecka Aleksander Edelman Æ Michel Goossens Pascale Fanen A neutral variant involved in a complex CFTR allele contributes to a severe cystic fibrosis phenotype Received: 1 September 2004 / Accepted: 12 December 2004 / Published online: 3 March 2005 Ó Springer-Verlag 2005 Abstract In order to further elucidate the contribution of complex alleles to the wide phenotypic variability of cystic fibrosis (CF), we investigated the structure-function relationships of a severe CF-associated complex allele [p.S912L;p.G1244V]. Login to comment
2 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:2:21
status: NEW
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ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:2:7
status: NEW
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Both p.G1244V and [p.S912L;p.G1244V] mutants had normal protein processing but markedly decreased ClÀ channel activity compared with wild-type. Login to comment
3 ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:3:102
status: NEW
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Notably, the double mutant displayed a dramatic decrease in ClÀ channel activity compared with p.G1244V (P<0.001). Login to comment
4 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:4:2
status: NEW
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p.S912L had normal protein processing and no detectable impact on CFTR function. Login to comment
5 ABCC7 p.Arg709*
X
ABCC7 p.Arg709* 15744523:5:90
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:5:25
status: NEW
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In other respects, the p.S912L variation was identified in compound heterozygosity with p.R709X in a healthy fertile man. Login to comment
6 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:6:54
status: NEW
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Together, these data strongly support the view that p.S912L in isolation should be considered as a neutral variant but one that might significantly impair CFTR function when inherited in cis with another CFTR mutation. Login to comment
12 ABCC7 p.Arg334Trp
X
ABCC7 p.Arg334Trp 15744523:12:131
status: NEW
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ABCC7 p.Arg347His
X
ABCC7 p.Arg347His 15744523:12:219
status: NEW
view ABCC7 p.Arg347His details
ABCC7 p.Arg347His
X
ABCC7 p.Arg347His 15744523:12:380
status: NEW
view ABCC7 p.Arg347His details
ABCC7 p.Asp1270Asn
X
ABCC7 p.Asp1270Asn 15744523:12:370
status: NEW
view ABCC7 p.Asp1270Asn details
ABCC7 p.Arg74Trp
X
ABCC7 p.Arg74Trp 15744523:12:200
status: NEW
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ABCC7 p.Arg1158*
X
ABCC7 p.Arg1158* 15744523:12:360
status: NEW
view ABCC7 p.Arg1158* details
ABCC7 p.Arg553Gln
X
ABCC7 p.Arg553Gln 15744523:12:110
status: NEW
view ABCC7 p.Arg553Gln details
The combination of two missense mutations on the same chromo some has been described clinically to lessen ([p.R553Q;p.F508del], [p.R334W;p.R1158X]; Dork et al. 1991; Duarte et al. 1996) or worsen ([p.R74W;p.D1270N], [p.R347H;p.D979A]; Casals et al. 1995; Hojo et al. 1998) the phenotype of CF patients with regard to the commonest mutation alone (p.F508del, p.R1158X, p.D1270N, p.R347H). Login to comment
14 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:14:7
status: NEW
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The [p.S912L;p.G1244V] double-mutant allele is associated with severe CF (Savov et al. 1995). Login to comment
16 ABCC7 p.Arg709*
X
ABCC7 p.Arg709* 15744523:16:80
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:16:90
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:16:131
status: NEW
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In vitro experiments and identification of a healthy fertile man bearing the [p.R709X]+[p.S912L] genotype both indicate that the p.S912L mutation should be considered to be a polymorphism. Login to comment
17 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:17:35
status: NEW
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ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:17:47
status: NEW
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ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:17:724
status: NEW
view ABCC7 p.Gly1244Val details
Surprisingly, the combination of p.S912L and p.G1244V decreases J. Clain Æ J. Lehmann-Che Æ E. Girodon M. Goossens Æ P. Fanen (&) Service de Biochimie et Ge´ ne´ tique, Hoˆ pital Henri Mondor, Institut National de la Sante´ et de la Recherche Me´ dicale U.468, AP-HP, 94010 Cre´ teil, France E-mail: pascale.fanen@im3.inserm.fr Tel.: +33-1-49812854 Fax: +33-1-48993345 J. Lipecka Æ A. Edelman Faculte´ de Me´ decine Necker, Institut National de la Sante´ et de la Reche0rche Me´ dicale U.467, 156 Rue de Vaugirard, 75015 Paris, France Hum Genet (2005) 116: 454-460 DOI 10.1007/s00439-004-1246-z cAMP-dependent ClÀ channel activity compared with p.G1244V, highlighting the deleterious effect exerted by polymorphisms on the phenotype when combined in cis with a mutation. Login to comment
54 ABCC7 p.Arg709*
X
ABCC7 p.Arg709* 15744523:54:165
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:54:255
status: NEW
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The diagnosis of CF was confirmed in the fetus by the presence of two allelic mutations, 711+1G fi T, a splice mutation of intron 5 inherited from the mother, and p.R709X, a nonsense mutation of exon 13 inherited from the father; the father carried the p.S912L variant (not transmitted to the fetus) on the other chromosome. Login to comment
56 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:56:96
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:56:119
status: NEW
view ABCC7 p.Ser912Leu details
ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:56:105
status: NEW
view ABCC7 p.Gly1244Val details
Results Processing of CFTR mutants To analyse the processing and ClÀ channel activity of p.S912L, p.G1244V and [p.S912L;p.G1244V] mutant proteins, wild-type and mutant CFTR alleles were expressed in HeLa cells. Login to comment
63 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:63:134
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:63:157
status: NEW
view ABCC7 p.Ser912Leu details
ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:63:143
status: NEW
view ABCC7 p.Gly1244Val details
The kinetics of core-glycosylated and mature forms of mutant CFTRs were nearly identical to those of the wild-type, indicating that p.S912L, p.G1244V and [p.S912L;p.G1244V] mutations did not affect maturation of the CFTR protein. Login to comment
75 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:75:2
status: NEW
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p.S912L- transfected cells displayed a similar proportion of responsive cells to wild-type cells (92% of responsive cells vs 83%; P>0.2; Fig.3), suggesting that ClÀ channel function was not affected by this mutation. Login to comment
76 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:76:9
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:76:36
status: NEW
view ABCC7 p.Ser912Leu details
ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:76:22
status: NEW
view ABCC7 p.Gly1244Val details
ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:76:45
status: NEW
view ABCC7 p.Gly1244Val details
Unlike p.S912L, the p.G1244V and [p.S912L; p.G1244V] CFTR transfected cells showed a marked decrease in cAMP-stimulated ClÀ conductance compared with wild-type (43% and 2.4% of responsive cells, respectively vs. Login to comment
79 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:79:28
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:79:93
status: NEW
view ABCC7 p.Ser912Leu details
ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:79:216
status: NEW
view ABCC7 p.Gly1244Val details
Surprisingly, whereas the p.S912L mutation had no detectable impact on CFTR function, the [p.S912L;p.G1244V] complex allele showed an almost 20-fold reduction in cAMP-dependent conductive pathway compared with the p.G1244V deleterious mutant (2.4% of responsive cells vs. Login to comment
81 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:81:59
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:81:99
status: NEW
view ABCC7 p.Ser912Leu details
ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:81:71
status: NEW
view ABCC7 p.Gly1244Val details
Discussion Clinical data suggest that the combination of p.S912L and p.G1244V mutations in cis ([p.S912L;p.G1244V] complex allele) produces a severe CF phenotype similar to that of p.F508del homozygotes. Login to comment
83 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:83:249
status: NEW
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Thus, the poor ClÀ channel activity measured in vitro (2.4% of the wild-type) and the severity of the associated disease observed in vivo (pancreatic insufficiency, severe lung disease and elevated sweat electrolytes) both indicate that the [p.S912L;p.G1244V] complex allele should be considered to be a severe allele. Login to comment
85 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:85:344
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:85:362
status: NEW
view ABCC7 p.Ser912Leu details
ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:85:565
status: NEW
view ABCC7 p.Ser912Leu details
ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:85:352
status: NEW
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In this study, we have Fig. 2 a-d Pulse-chase experiments showing the turnover of the immature and mature forms of wild-type and the mutant CFTR proteins (representative of two independent experiments) Table 1 Summary of MEQ fluorescence assay results from mock-transfected, wild-type and mutant cells Statistic DFstim-DFbasal Mock Wild-type p.S912L p.G1244V [p.S912L;p.G1244V] n 28 64 36 53 42 Mean 0.002 0.023 0.036 0.005 0.001 SEM 0.001 0.017 0.028 0.005 0.001 Range 0-0.005 0-0.340 0-0.140 0-0.034 0-0.006 provided functional and clinical evidence that the p.S912L mutation is not a disease-causing mutation on the basis of the following data. Login to comment
86 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:86:47
status: NEW
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(1) In vitro experiments have shown that the p.S912L mutation has no detectable impact on CFTR processing and ClÀ channel function. Login to comment
89 ABCC7 p.Arg709*
X
ABCC7 p.Arg709* 15744523:89:178
status: NEW
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ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:89:57
status: NEW
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Notably, the healthy father of a CF fetus carrying the p.S912L mutation has been identified in our laboratory in the framework of prenatal diagnosis, whereas the CF-associated p.R709X mutation (Bonizzato et al. 1995) has been detected on his other allele. Login to comment
91 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:91:58
status: NEW
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Together, these data strongly support the view that the p.S912L mutation should be considered to be a neutral variant. Login to comment
94 ABCC7 p.Gly1244Glu
X
ABCC7 p.Gly1244Glu 15744523:94:49
status: NEW
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At the same location, the severe CF-associated p.G1244E mutation (Devoto et al. 1991) exhibits a defect in the open state probability of the CFTR protein (Anderson and Welsh 1992). Login to comment
95 ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:95:55
status: NEW
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Taken together, these data support the view that the p.G1244V mutation is a disease-causing mutation. Login to comment
96 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:96:34
status: NEW
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ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:96:20
status: NEW
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Surprisingly, the p.G1244V and [p.S912L;p.G1244V] alleles affect in vitro ClÀ channel function in different ways. Login to comment
97 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:97:27
status: NEW
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ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:97:39
status: NEW
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ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:97:151
status: NEW
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This might indicate that p.S912L and p.G1244V mutations occurring on the same allele cause severe structural alterations worsening the effect of the p.G1244V mutation on CFTR function. Login to comment
98 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:98:54
status: NEW
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However, we cannot exclude the possibility that the p.S912L mutation may have a slight, but undetectable, effect on CFTR function and that a threshold is reached when these two mutations are combined in cis. Login to comment
99 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:99:109
status: NEW
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ABCC7 p.Gly1244Val
X
ABCC7 p.Gly1244Val 15744523:99:131
status: NEW
view ABCC7 p.Gly1244Val details
An important consequence of our observation is that when a patient or an asymptomatic relative carries the p.S912L mutation, the p.G1244V mutation should be sought in order to exclude a CF allele; this is important for genetic counselling. Login to comment
100 ABCC7 p.Ser912Leu
X
ABCC7 p.Ser912Leu 15744523:100:117
status: NEW
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These results have important implications for CF because they suggest that ''neutral`` missense mutations, such as p.S912L, might significantly alter CFTR function when inherited in cis with another mutation. Login to comment
103 ABCC7 p.Arg117His
X
ABCC7 p.Arg117His 15744523:103:115
status: NEW
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ABCC7 p.Arg117His
X
ABCC7 p.Arg117His 15744523:103:189
status: NEW
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The length of a polythymidine tract in the 3' splice site of intron 8 modulates the clinical presentation of the p.R117H missense mutation because of a dramatic decrease in the amount of p.R117H-CFTR transcript (Kiesewetter et al. 1993). Login to comment
105 ABCC7 p.Ser549Arg
X
ABCC7 p.Ser549Arg 15744523:105:75
status: NEW
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The sequence change À102T fi A attenuates the effects of the severe p.S549R (T fi G) missense mutation by causing a significant increase in CFTR expression in vitro. Login to comment
106 ABCC7 p.Ser549Arg
X
ABCC7 p.Ser549Arg 15744523:106:111
status: NEW
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ABCC7 p.Ser549Arg
X
ABCC7 p.Ser549Arg 15744523:106:215
status: NEW
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This explains the striking differences in genotype-phenotype correlations between patients carrying mutation p.S549R alone, who presented severe disease, and patients carrying the complex allele [À102T fi A; p.S549R], who exhibit milder forms of CF (Romey et al. 2000). Login to comment
118 ABCC7 p.Leu436Phe
X
ABCC7 p.Leu436Phe 15744523:118:151
status: NEW
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The complex allele [p.R201C;p.L436F] has recently been reported (Caciotti et al. 2003); expression studies have revealed a deleterious effect of the p.L436F polymorphism on the known p.R201C mutation resulting in a late infantile subtype of type-II GM1, instead of the juvenile form classically associated with p.R201C. Login to comment