chr17-7675208-C-T
Variant summary
Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1PM2PP3_StrongPP5
The NM_000546.6(TP53):c.404G>A(p.Cys135Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,832 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000546.6 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 9 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 33
GnomAD4 exome AF: 0.00000137 AC: 2AN: 1461832Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0AN XY: 727204
GnomAD4 genome Cov.: 33
ClinVar
Submissions by phenotype
not provided Pathogenic:2
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Hereditary cancer-predisposing syndrome Pathogenic:2
This missense variant replaces cysteine with tyrosine at codon 135 of the TP53 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Experimental studies have shown that this variant yields protein that is non-functional in yeast transactivation assays (PMID: 12826609, 15017592, 16861262, 20407015), human cell proliferation assays (PMID: 29979965), and human cell growth suppression assays (PMID: 16247456, 30224644). This variant has been reported in a Chinese individual affected with gastric cancer (PMID: 21080251) and in a Chinese individual with sporadic triple-negative breast cancer carrying a second variant in MSH6 (PMID: 30630526). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Likely Pathogenic. -
The p.C135Y pathogenic mutation (also known as c.404G>A), located in coding exon 4 of the TP53 gene, results from a G to A substitution at nucleotide position 404. The cysteine at codon 135 is replaced by tyrosine, an amino acid with highly dissimilar properties. This variant has been reported in one Chinese patient diagnosed with sporadic triple negative breast cancer; this individual also carried a likely pathogenic variant in the MSH6 gene (Yi D et al. Hum. Genomics. 2019 01;13:4). This variant has been observed numerous times as a somatic mutation in the cancerhotspots.org database (Chang MT et al. Cancer Discov. 2018 02;8:174-183). This variant was detected in at least one individual at an allele fraction that is suggestive of clonal hematopoiesis, a predictor of TP53 pathogenicity (Ambry internal data; Fortuno C et al. Genet Med. 2022 03;24:673-680). This variant is in the DNA binding domain of the TP53 protein and is reported to have non-functional transactivation in yeast based assays (Kato S et al. Proc Natl Acad Sci USA. 2003 Jul 8;100(14):8424-9; Dearth LR et al. Carcinogenesis. 2007 Feb; 28(2):289-98; Jordan JJ et al. Mol. Cancer Res. 2010 May;8(5):701-16). Studies conducted in human cell lines indicate this alteration is deficient at growth suppression and has a dominant negative effect (Kotler E et al. Mol. Cell 2018 Jul;71:178-190.e8; Giacomelli AO et al. Nat. Genet. 2018 Oct;50:1381-1387). Internal structural analysis suggests this variant, which is a buried residue in the secondary shell of the DNA binding surface, is structurally destabilizing (Cho Y et al. Science. 1994 Jul 15;265(5170):346-55; Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the supporting evidence, this variant is interpreted as a disease-causing mutation. -
Li-Fraumeni syndrome 1 Pathogenic:1
This variant is considered likely pathogenic. Functional studies indicate this variant impacts protein function [PMID: 7651740, 16247456, 29979965]. This variant is expected to disrupt protein structure [Myriad internal data]. -
Li-Fraumeni syndrome Uncertain:1
This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 135 of the TP53 protein (p.Cys135Tyr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with breast cancer at an allele fraction of 0.16 (PMID: 30630526). ClinVar contains an entry for this variant (Variation ID: 141762). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 12826609, 29979965, 30224644) indicates that this missense variant is expected to disrupt TP53 function with a positive predictive value of 97.5%. Experimental studies have shown that this missense change affects TP53 function (PMID: 12826609, 29979965, 30224644). 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. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at