Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The ENST00000233146.7(MSH2):c.1777C>T(p.Gln593Ter) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★★). Synonymous variant affecting the same amino acid position (i.e. Q593Q) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.
MSH2 (HGNC:7325): (mutS homolog 2) This locus is frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). When cloned, it was discovered to be a human homolog of the E. coli mismatch repair gene mutS, consistent with the characteristic alterations in microsatellite sequences (RER+ phenotype) found in HNPCC. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]
Verdict is Pathogenic. Variant got 18 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 2-47475042-C-T is Pathogenic according to our data. Variant chr2-47475042-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 90783.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47475042-C-T is described in Lovd as [Pathogenic].
For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 90783). This premature translational stop signal has been observed in individual(s) with Lynch syndrome (PMID: 15235038, 27601186). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Gln593*) in the MSH2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MSH2 are known to be pathogenic (PMID: 15849733, 24362816). -
The p.Q593* pathogenic mutation (also known as c.1777C>T), located in coding exon 12 of the MSH2 gene, results from a C to T substitution at nucleotide position 1777. This changes the amino acid from a glutamine to a stop codon within coding exon 12. This mutation has been reported in multiple individuals with hereditary non-polyposis colorectal cancer (HNPCC)/Lynch syndrome, including patients meeting Amsterdam criteria and/or whose tumors demonstrated loss of MSH2 by immunohistochemistry (IHC) (Naseem H et al. Clin Genet, 2006 Nov;70:388-95; Lagerstedt-Robinson K et al. Oncol Rep, 2016 Nov;36:2823-2835; Sunga AY et al. Cancer Genet, 2017 04;212-213:1-7; Gong R et al. Cancer Manag Res, 2019 Apr;11:3721-3739; Tian W et al. Int J Cancer, 2019 09;145:1290-1298; Wischhusen JW et al. Cancer Epidemiol Biomarkers Prev, 2020 01;29:193-199). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -