rs193922506
Variant summary
Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP2
The NM_000492.4(CFTR):c.2597G>A(p.Cys866Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.0000763 in 1,612,548 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C866R) has been classified as Uncertain significance.
Frequency
Consequence
NM_000492.4 missense
Scores
Clinical Significance
Conservation
Publications
- cystic fibrosisInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Orphanet
- congenital bilateral absence of vas deferensInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- hereditary chronic pancreatitisInheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
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ACMG classification
Our verdict: Uncertain_significance. The variant received 1 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| CFTR | NM_000492.4 | c.2597G>A | p.Cys866Tyr | missense_variant | Exon 15 of 27 | ENST00000003084.11 | NP_000483.3 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| CFTR | ENST00000003084.11 | c.2597G>A | p.Cys866Tyr | missense_variant | Exon 15 of 27 | 1 | NM_000492.4 | ENSP00000003084.6 |
Frequencies
GnomAD3 genomes AF: 0.0000658 AC: 10AN: 151964Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000478 AC: 12AN: 251302 AF XY: 0.0000515 show subpopulations
GnomAD4 exome AF: 0.0000774 AC: 113AN: 1460468Hom.: 0 Cov.: 31 AF XY: 0.0000688 AC XY: 50AN XY: 726586 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000658 AC: 10AN: 152080Hom.: 0 Cov.: 32 AF XY: 0.000121 AC XY: 9AN XY: 74334 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Cystic fibrosis Uncertain:5
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The p.C866Y variant (also known as c.2597G>A), located in coding exon 15 of the CFTR gene, results from a G to A substitution at nucleotide position 2597. The cysteine at codon 866 is replaced by tyrosine, an amino acid with highly dissimilar properties. This alteration has been described in a patient with echogenic bowel, but no other symptoms were reported (Ferec et al. Cystic Fibrosis Mutation Database [database online] Toronto, ON, Canada: SickKids; 1991; Tsui LC. Hum. Mutat., 1992;1:197-203). In addition, this alteration has been detected in individuals with nonspecific heart and lung phenotypes via whole exome sequencing and in individuals with cystic fibrosis; however, no specific clinical details were provided (Tabor HK et al. Am. J. Hum. Genet., 2014 Aug;95:183-93; Salvatore F et al. Am. J. Med. Genet., 2002 Jul;111:88-95; Ravnik-Glavac M et al. Hum. Mol. Genet., 1994 May;3:801-7; Claustres M et al. Hum. Mutat., 2000;16:143-56; Amorim CEG et al. PLoS Genet., 2017 Sep;13:e1006915). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
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This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 866 of the CFTR protein (p.Cys866Tyr). This variant is present in population databases (rs193922506, gnomAD 0.02%). This missense change has been observed in individual(s) with CFTR-related conditions (PMID: 1284534, 10923036, 11379874). ClinVar contains an entry for this variant (Variation ID: 35843). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt CFTR protein function with a positive predictive value of 80%. 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. -
not specified Uncertain:1
Variant summary: CFTR c.2597G>A (p.Cys866Tyr) results in a non-conservative amino acid change located in the ABC transporter type 1, transmembrane domain (IPR011527) of the encoded protein sequence. Four of four in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4.8e-05 in 251302 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in CFTR causing Cystic Fibrosis (4.8e-05 vs 0.013), allowing no conclusion about variant significance. c.2597G>A has been reported in the literature in 1 homozygous individual with Cystic Fibrosis without detailed clinical presentations (Baaran_2021) and in at least one individual affected with Cystic Fibrosis without a reported second variant (Tsui_1992, Le Marechal_2001). These reports do not provide unequivocal conclusions about association of the variant with Cystic Fibrosis. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect resulted in approximately (Gt channel conductance) 13% of normal chloride channel conductance relative to wild type (e.g., Bihler_2024). The following publications have been ascertained in the context of this evaluation (PMID: 12124743, 7521710, 10923036, 1284534, 8844213, 11379874, 19139070, 25087612, 25735457, 34996830, 35110256). ClinVar contains an entry for this variant (Variation ID: 35843). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -
not provided Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at