NM_000251.3:c.446G>A
Variant summary
Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM2PM5PP3_StrongPP5
The NM_000251.3(MSH2):c.446G>A(p.Gly149Asp) variant causes a missense change. The variant allele was found at a frequency of 0.00000657 in 152,176 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G149S) has been classified as Likely benign.
Frequency
Consequence
NM_000251.3 missense
Scores
Clinical Significance
Conservation
Publications
- Lynch syndromeInheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, ClinGen, Orphanet
- Lynch syndrome 1Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Ambry Genetics
- Muir-Torre syndromeInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, G2P
- mismatch repair cancer syndrome 1Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
- mismatch repair cancer syndrome 2Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
- ovarian cancerInheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
- malignant pancreatic neoplasmInheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
- prostate cancerInheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
- rhabdomyosarcomaInheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
- breast cancerInheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics
- hereditary breast carcinomaInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Likely_pathogenic. The variant received 9 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152176Hom.: 0 Cov.: 31 show subpopulations
GnomAD4 exome Cov.: 32
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152176Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0AN XY: 74332 show subpopulations ⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
ClinVar
Submissions by phenotype
Lynch syndrome 1 Pathogenic:1Uncertain:1
This variant is considered likely pathogenic. Functional studies indicate this variant impacts protein function [PMID: 33357406]. This variant is expected to disrupt protein structure [Myriad internal data]. -
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Hereditary cancer-predisposing syndrome Pathogenic:1
The p.G149D variant (also known as c.446G>A), located in coding exon 3 of the MSH2 gene, results from a G to A substitution at nucleotide position 446. The glycine at codon 149 is replaced by aspartic acid, an amino acid with similar properties. This variant was identified in a proband with colorectal cancer diagnosed at age 37 (Chao EC et al. Hum. Mutat. 2008 Jun;29:852-60). This variant has been identified in a proband whose Lynch syndrome-associated tumor demonstrated high microsatellite instability and partial loss of MSH2/MSH6 expression by immunohistochemistry (Ambry internal data). In a massively parallel cell-based functional assay testing susceptibility to a DNA damaging agent, 6-thioguanine (6-TG), this variant was reported to be functionally deleterious (Jia X et al. Am J Hum Genet, 2021 Jan;108:163-175). This amino acid position is highly conserved through mammals but not in all 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. -
Carcinoma of colon Uncertain:1
The MSH2 p.Gly149Asp variant was not identified in the literature nor was it identified in the UMD-LSDB database. The variant was also identified in dbSNP (ID: rs587779162) as "With Uncertain significance allele", and in ClinVar (classified as uncertain significance by InSight). The variant was not identified in the following control databases: the Exome Aggregation Consortium (August 8th 2016), or the Genome Aggregation Database (Feb 27, 2017). The p.Gly149 residue is conserved in mammals but not in more distantly related organisms, and four out of five computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the aspartic acid variant may impact the protein; however, this information is not predictive enough to assume pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -
Hereditary nonpolyposis colorectal neoplasms Uncertain:1
This sequence change replaces glycine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 149 of the MSH2 protein (p.Gly149Asp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with colorectal cancer (PMID: 18383312). ClinVar contains an entry for this variant (Variation ID: 91099). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 33357406) indicates that this missense variant is expected to disrupt MSH2 function with a positive predictive value of 95%. 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