rs397508469
Variant summary
Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1PM2PP3_Strong
The NM_000492.4(CFTR):c.2981T>G(p.Phe994Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000773 in 1,551,412 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Consequence
NM_000492.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 8 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
CFTR | NM_000492.4 | c.2981T>G | p.Phe994Cys | missense_variant | Exon 18 of 27 | ENST00000003084.11 | NP_000483.3 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152158Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.00000398 AC: 1AN: 251096Hom.: 0 AF XY: 0.00000737 AC XY: 1AN XY: 135728
GnomAD4 exome AF: 0.00000715 AC: 10AN: 1399254Hom.: 0 Cov.: 24 AF XY: 0.00000857 AC XY: 6AN XY: 700142
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152158Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74328
ClinVar
Submissions by phenotype
Cystic fibrosis Uncertain:3Other:1
This sequence change replaces phenylalanine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 994 of the CFTR protein (p.Phe994Cys). This variant is present in population databases (rs397508469, gnomAD 0.0009%). This missense change has been observed in individual(s) with cystic fibrosis (PMID: 28603918). ClinVar contains an entry for this variant (Variation ID: 53612). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
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The p.F994C variant (also known as c.2981T>G), located in coding exon 18 of the CFTR gene, results from a T to G substitution at nucleotide position 2981. The phenylalanine at codon 994 is replaced by cysteine, an amino acid with highly dissimilar properties. This variant was reported in conjunction with (TG)12-5T in an individual in the CFTR-France database who was diagnosed with congenital bilateral absence of vas deferens (CBAVD) however phase information was limited (Claustres M et al. Hum. Mutat., 2017 10;38:1297-1315). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -
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not specified Uncertain:2
The CFTR c.2981T>G; p.Phe994Cys variant (rs397508469) is reported in an individual with congenital bilateral absence of the vas deferens (CBAVD) who also carries 5T on the same allele and F508del on the other allele (see database link). This variant is reported as uncertain in ClinVar (Variation ID: 53612). This variant is only observed on one allele in the Genome Aggregation Database, indicating it is not a common polymorphism. The phenylalanine at codon 994 is highly conserved, and computational analyses (SIFT, PolyPhen-2) predict that this variant is deleterious. However, given the lack of clinical and functional data, the significance of this variant is uncertain at this time. REFERENCES Link to SickKids database: http://www.genet.sickkids.on.ca/cftr/MutationDetailPage.external?sp=797 -
Variant summary: CFTR c.2981T>G (p.Phe994Cys) results in a non-conservative amino acid change located in the transmembrane domain (IPR011527) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4.1e-06 in 245896 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. The variant of interest has been reported in the literature and in multiple databases in a male patient affected with Congenital Bilateral Absence of the Vas Deferens (CBAVD) who carried a severe disease variant (likely deltaF508) on the other allele (Dorfman 2010, Claustres 2017); however this patient also carried a mild pathogenic variant (TG12T5) in cis, which could explain his phenotype. These reports therefore do not provide unequivocal conclusions about association of the variant with Cystic Fibrosis. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 28603918, 20059485, 25735457). ClinVar contains an entry for this variant (Variation ID: 53612). Based on the evidence outlined above, the variant was classified as uncertain significance. -
CFTR-related disorder Uncertain:1
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not provided Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at