chr2-47414291-C-T
Variant summary
Our verdict is Benign. Variant got -10 ACMG points: 0P and 10B. BP4_ModerateBP6_Very_Strong
The NM_000251.3(MSH2):c.815C>T(p.Ala272Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000267 in 1,612,784 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★★).
Frequency
Consequence
NM_000251.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -10 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000415 AC: 63AN: 151678Hom.: 1 Cov.: 29
GnomAD3 exomes AF: 0.000303 AC: 76AN: 250724Hom.: 0 AF XY: 0.000317 AC XY: 43AN XY: 135486
GnomAD4 exome AF: 0.000251 AC: 367AN: 1461106Hom.: 1 Cov.: 32 AF XY: 0.000239 AC XY: 174AN XY: 726828
GnomAD4 genome AF: 0.000415 AC: 63AN: 151678Hom.: 1 Cov.: 29 AF XY: 0.000500 AC XY: 37AN XY: 74040
ClinVar
Submissions by phenotype
not specified Uncertain:2Benign:2
Variant summary: MSH2 c.815C>T (p.Ala272Val) results in a non-conservative amino acid change located in the connector domain (IPR007860) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00031 in 252008 control chromosomes, predominantly at a frequency of 0.00041 within the Non-Finnish European subpopulation in the gnomAD database. This frequency is close to that estimated for a pathogenic variant in MSH2 causing Lynch Syndrome (0.00041 vs 0.00057), supporting a benign role for the variant of interest. c.815C>T has been reported in the literature in individuals affected with Lynch Syndrome, as well as colorectal-, pancreatic-, breast- and skin cancers (example, Lin_1999, Ollila_2006, Nilbert_2009, Samowitz_2001, Syngal_1999, Yang_2016, Dominguez-Valentin_2018, Cho_2018, Young_2018). These report(s) do not provide unequivocal conclusions about association of the variant with Hereditary Nonpolyposis Colorectal Cancer/Lynch syndrome. <ultiple co-occurrences with other pathogenic variants have been reported (MSH2 c.518T>G / p.Leu173Arg, in the UMD database; MLH1 del exon 6, Mueller_2009; BRCA2 c.9382C>T / p.Arg3128X, Domingues-Valentin_2018), providing supporting evidence for a benign role. Several publications report experimental evidence evaluating the impact of MSH2 c.815C>T on protein function. The variant was shown to mildly affect the normal splicing pattern by causing exon 5 exclusion (Tournier_2008, Lastella_2006, Dominguez-Valentin_2018), however tumors in mutation carriers showed normal MSH2 expression (Ollila_2006). In addition, the variant was shown to be MMR-proficient by the in vitro MMR assay as reported by several independent research groups (Ollila_2006, Ollila_2008, Drost_2011). Taken together these results indicate that this variant does not significantly damage MSH2 protein function. Multiple clinical diagnostic laboratories and an expert panel (InSiGHT) have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple submitters reported the variant with conflicting assessments with the expert panel and five other submitters reporting a benign/likely benign outcome. Based on the absence of evidence supporting an actionable outcome in literature spanning over two decades of evolution as outlined above, the variant was re-classified as benign. -
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Variant classified as Uncertain Significance - Favor Benign. The p.Ala272Val variant in MSH2 has been reported in at least 11 individuals with Lynch Syndrome-related cancers (Ollila 2006, Mueller 2009, InSiGHT database (http://chromium.lovd.nl/LOVD2/colon_cancer/variants.php)). One of these patients carried a second pathogenic variant in MLH1. In vitro functional studies provide some evidence that the p.Ala272Val variant may have a slight impact on the protein (Tournier 2008, Lastella 2006), however others demonstrate an effect comparable to that in the wild-type (Ollila 2006). These types of assays may not accurately represent biological function. This variant has been identified in 11/10358 Ashkenazi Jewish chromosomes (0.1%) by the Genome Aggregation Consortium (GnomAD, http://gnomad.broadinstitute.org). Computational prediction tools and conservation analysis do not provide strong support for or against an impact to the protein. In addition, it has been classified as Uncertain Significance on Sep 5, 2013 by the ClinGen-approved InSiGHT expert panel (ClinVar SCV000107764.2). In summary, the clinical significance of the p.Ala272Val variant is uncertain. -
not provided Uncertain:1Benign:3
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This variant is associated with the following publications: (PMID: 21120944, 22102614, 16995940, 27449771, 29371908, 10080150, 22949387, 18951462, 17101317, 19690142, 15872200, 20587412, 18561205, 11606497, 18566915, 25637381, 17594722, 22703879, 26951660, 25569433, 27328445, 10422993, 32741062) -
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Hereditary cancer-predisposing syndrome Benign:4
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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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Lynch syndrome 1 Uncertain:1Benign:2
This variant is considered benign. This variant has been observed in trans with a known pathogenic variant in one or more individuals lacking clinical features consistent with gene-specific recessive disease. 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]. -
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Lynch syndrome Benign:2
Multifactorial likelihood analysis posterior probability <0.001 -
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Colorectal cancer, non-polyposis Uncertain:1
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MSH2-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Breast and/or ovarian cancer Benign:1
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Hereditary nonpolyposis colorectal neoplasms Benign:1
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Malignant tumor of breast Benign:1
The MSH2 p.Ala272Val variant was identified in 1 of 1132 proband chromosomes (frequency: 0.001) from individuals or families with colorectal cancer (Hampel 2005). The variant was also identified in dbSNP (ID: rs34136999) as “With other allele”, in ClinVar (classified as benign by Invitae; likely benign by GeneDx, Ambry Genetics, color Genomics; uncertain significance by 5 clinical laboratories), Clinvitae (conflicting interpretations of pathogenicity), MutDB, UMD-LSDB (classified as neutral), Mismatch Repair Genes Variant Database, Insight Hereditary Tumors Database, databases. In UMD the variant was identified with a co-occurring pathogenic MSH2 variant (c.518T>G, p.Leu173Arg), increasing the likelihood that the p.Ala272Val variant does not have clinical significance. The variant was not identified in GeneInsight-COGR, Cosmic, Zhejiang Colon Cancer Database, databases. The variant was identified in control databases in 77 of 276232 chromosomes at a frequency of 0.0003 (Genome Aggregation Database Feb 27, 2017). Breakdown of the observations by population include African in 2 of 23984 chromosomes (freq: 0.0001), Other in 2 of 6438 chromosomes (freq: 0.0003), Latino in 14 of 34346 chromosomes (freq: 0.0004), European Non-Finnish in 49 of 126334 chromosomes (freq: 0.0004), Ashkenazi Jewish in 9 of 10140 chromosomes (freq: 0.001), and South Asian in 1 of 30510 chromosomes (freq: 0.00003), while the variant was not observed in the East Asian, European Finnish, populations. Several functional studies demonstrated this variant resulted in partial exon 5 skipping (Lastella 2006, Tournier 2008) and slightly reduced mismatch binding of the MMR reaction (Ollila 2008). The variant showed no reduction in mismatch repair capability compared with the wild-type MSH2 (Ollila 2006). In addition, the variant was identified with a pathogenic BRCA2 c.9382C>T in a patient diagnosed with ductal carcinoma at 44 years of age (Dominguez-Valentin 2018). The p.Ala272 residue is conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) provide inconsistent predictions regarding the impact to the protein; this information is not very predictive of pathogenicity. The variant occurs outside of the splicing consensus sequence and 1 of 5 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predict a greater than 10% difference in splicing; this is not very predictive of pathogenicity. In summary, based on the above information, the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more benign role for this variant. This variant is classified as likely benign. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at