rs63751328
Variant summary
Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong
The NM_000179.3(MSH6):c.3577G>A(p.Glu1193Lys) variant causes a missense 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. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E1193A) has been classified as Uncertain significance.
Frequency
Consequence
NM_000179.3 missense
Scores
Clinical Significance
Conservation
Publications
- intellectual developmental disorder with dysmorphic facies and behavioral abnormalitiesInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
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ACMG classification
Our verdict: Pathogenic. The variant received 18 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 33
GnomAD4 exome Cov.: 33
GnomAD4 genome Cov.: 33
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Pathogenic:2
This missense variant replaces glutamic acid with lysine at codon 1193 of the MSH6 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). Functional studies have shown that this variant protein results in impaired DNA mismatch repair activity and reduced association with the MSH2 protein (PMID: 15354210). Another functional study has shown that the equivalent variant protein (p.Glu1191Lys) in mice also results in impaired DNA mismatch repair activity (PMID: 28531214). This variant has been reported in two individuals affected with endometrial cancer (PMID: 15354210, 16885385, 28531214), with microsatellite instability and/or loss of MSH6 protein expression reported in tumor samples. This variant has been reported in individuals affected with clinical features of Lynch syndrome (ClinVar SCV001492013.3). 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.E1193K variant (also known as c.3577G>A), located in coding exon 7 of the MSH6 gene, results from a G to A substitution at nucleotide position 3577. The glutamic acid at codon 1193 is replaced by lysine, an amino acid with similar properties. This alteration has been identified in two unrelated individuals diagnosed with endometrial cancer at ages 59 and 60, respectively, whose tumors showed high microsatellite instability (MSI-H) with loss of MSH6 staining on immunohistochemistry (IHC) (Kariola R et al. Br. J. Cancer, 2004 Oct;91:1287-92; Belvederesi L et al. Fam. Cancer. 2012 Dec;11:675-80). An in vivo mismatch repair (MMR) assay demonstrated that the E1193K variant displayed complete MMR deficiency at 0%. Additionally, a co-immunoprecipitation assay showed that the E1193K protein co-precipitated much less MSH2 compared to wildtype MSH6, suggesting interference in the heterodimerization between the MSH2 and MSH6 proteins (Kariola R et al. Br. J. Cancer. 2004 Oct;91:1287-92; Hampel H et al. Cancer Res. 2006 Aug;66:7810-7). In another study, the mouse equivalent of this variant was detected in a functional genetic screen and was shown to abrogate MMR activity (Houlleberghs H et al. PLoS Genet., 2017 May;13:e1006765). Based on an internal structural assessment, this alteration destabilizes the ATPase domain (Warren JJ et al. Mol. Cell, 2007 May;26:579-92). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -
Lynch syndrome 5 Pathogenic:1
This variant is considered pathogenic. Functional studies indicate this variant impacts protein function [PMID: 28531214, 15354210]. This variant is expected to disrupt protein structure [Myriad internal data]. This variant is strongly associated with more severe personal and family histories of cancer, typical for individuals with pathogenic variants in this gene [PMID: 27363726]. -
Hereditary nonpolyposis colon cancer Pathogenic:1
Variant summary: MSH6 c.3577G>A (p.Glu1193Lys) results in a conservative amino acid change located in the DNA mismatch repair protein MutS, C-terminal (IPR000432) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 249974 control chromosomes. c.3577G>A has been reported in the literature in individuals affected with endometrial cancer showing microsatellite instability and loss of MSH6 expression (Kariola_2004, Hampel_2006). These data indicate that the variant is likely associated with disease. At least two publications reports experimental evidence evaluating an impact on protein function, showing a loss of MMR activity and disruption of heterodimerisation with MSH2 (Kariola_2004, Houlleberghs_2017). Four submitters have provided clinical-significance assessments for this variant to ClinVar after 2014 , and all classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Lynch syndrome Pathogenic:1
This missense variant replaces glutamic acid with lysine at codon 1193 of the MSH6 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). Functional studies have shown that this variant protein results in impaired DNA mismatch repair activity and reduced association with the MSH2 protein (PMID: 15354210). Another functional study has shown that the equivalent variant protein (p.Glu1191Lys) in mice also results in impaired DNA mismatch repair activity (PMID: 28531214). This variant has been reported in two individuals affected with endometrial cancer (PMID: 15354210, 16885385, 28531214), with microsatellite instability and/or loss of MSH6 protein expression reported in tumor samples. This variant has been reported in individuals affected with clinical features of Lynch syndrome (ClinVar SCV001492013.3). 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. -
not provided Pathogenic:1
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Hereditary nonpolyposis colorectal neoplasms Pathogenic:1
This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 1193 of the MSH6 protein (p.Glu1193Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with clinical features of Lynch syndrome (PMID: 15354210, 16885385; external communication, internal data). ClinVar contains an entry for this variant (Variation ID: 89422). Invitae Evidence Modeling incorporating data from in vitro experimental studies (internal data) indicates that this missense variant is expected to disrupt MSH6 function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects MSH6 function (PMID: 15354210, 28531214). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Endometrial carcinoma Pathogenic:1
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Computational scores
Source:
Splicing
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