2-47416344-A-G
Variant summary
Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PP3_ModerateBP6_Strong
The NM_000251.3(MSH2):c.991A>G(p.Asn331Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000023 in 1,611,828 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_000251.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152236Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.00000795 AC: 2AN: 251462Hom.: 0 AF XY: 0.0000147 AC XY: 2AN XY: 135906
GnomAD4 exome AF: 0.0000226 AC: 33AN: 1459592Hom.: 0 Cov.: 29 AF XY: 0.0000207 AC XY: 15AN XY: 726328
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152236Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74370
ClinVar
Submissions by phenotype
Lynch syndrome 1 Uncertain:1Benign:2
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Variant reclassification due to new tumour Likelihood Ratios: Multifactorial likelihood analysis posterior probabilty is in class 3. (0.091) -
This variant is considered likely benign. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 27363726]. -
not provided Uncertain:2
Observed in individuals with colorectal or breast cancer (PMID: 16736289, 25186627); Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies demonstrate decreased mismatch repair activity, but no effect on splicing, binding partner interaction, and nuclear localization (PMID: 18561205, 30504929); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 24362816, 22290698, 16736289, 18561205, 25871441, 25186627, 29179779, 30212499, 30504929, 18822302, 21120944) -
The MSH2 c.991A>G (p.Asn331Asp) variant has been reported in the published literature in a family where this variant did not co-segregate with Lynch syndrome associated cancers (PMID: 16736289 (2006)). It was also reported in an individual affected with breast cancer (PMID: 25186627 (2015)). Functional studies of this variant show it had little to no effect on mismatch repair activity, localization, and MSH6 binding (PMID: 30504929 (2018), 33357406 (2021)), as well as on splicing (PMID: 18561205 (2008)). The frequency of this variant in the general population, 0.000008 (2/251462 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Based on the available information, we are unable to determine the clinical significance of this variant. -
Hereditary cancer-predisposing syndrome Benign:2
This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
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not specified Uncertain:1
Variant summary: MSH2 c.991A>G (p.Asn331Asp) results in a conservative amino acid change located in the DNA mismatch repair protein MutS, core domain (IPR007696) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251462 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. 5/5 computational tools predict no significant impact on normal splicing and ESE finder predicts that this variant may eliminate a SRp55 site and create a SRp40 site. These predictions have been tested functionally through a minigene assay which confirmed that the variant does not affect splicing, despite splicing computational tools suggesting ESE sites are predicted to be affected (Tournier_2008). However, a cell-free in vitro MMR activity assay showed that this variant had 62.4% MMR activity (Drost_2019). c.991A>G has been reported in the literature in individuals affected with Lynch Syndrome and breast cancer (Tung_2015, Tournier_2008, Spaepen_2006). One of the studies carried out additional analysis: tumor tissue from a patient was tested for microsatellite instability (0 of 10 loci were unstable), MSH2 protein expression (immunostaining showed both MSH2 and MLH1 as positive), and segregation with disease in the family (the variant did not segregate with disease in the 3 family members tested). Together, these analyses suggest the variant does not contribute to tumorigenesis (Spaepen_2006). Six ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance (n=2) and likely benign (n=4) including an expert panel (InSiGHT), following a recent re-classification, citing the variant as uncertain significance (originally classified as likely benign in 2013) citing new tumour Likelihood Ratios: Multifactorial likelihood analysis posterior probabilty is in class 3. (0.091). Based on the evidence outlined above, the variant was classified as VUS-possibly benign. -
Muir-Torré syndrome;C2936783:Lynch syndrome 1;C5436806:Mismatch repair cancer syndrome 2 Uncertain:1
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Lynch syndrome Benign:1
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Hereditary nonpolyposis colorectal neoplasms Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at