2-47800391-A-G
Variant summary
Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_ModerateBP6
The NM_000179.3(MSH6):āc.2408A>Gā(p.Asp803Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000508 in 1,614,124 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000179.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -3 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000526 AC: 8AN: 152152Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000838 AC: 21AN: 250694Hom.: 0 AF XY: 0.000111 AC XY: 15AN XY: 135486
GnomAD4 exome AF: 0.0000506 AC: 74AN: 1461854Hom.: 0 Cov.: 34 AF XY: 0.0000646 AC XY: 47AN XY: 727232
GnomAD4 genome AF: 0.0000525 AC: 8AN: 152270Hom.: 0 Cov.: 32 AF XY: 0.0000403 AC XY: 3AN XY: 74452
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Uncertain:4
The p.D803G variant (also known as c.2408A>G), located in coding exon 4 of the MSH6 gene, results from an A to G substitution at nucleotide position 2408. The aspartic acid at codon 803 is replaced by glycine, an amino acid with similar properties. This variant was first reported in a familial CRC kindred and has been shown to reduce the ATP-binding potential of MSH6 (Kolodner RD et al. Cancer Res. 1999 Oct;59:5068-74; Cyr JL and Heinen CD. J. Biol. Chem. 2008 Nov;283:31641-8). This alteration was also identified in an individual diagnosed with colorectal cancer (DeRycke MS et al. Mol Genet Genomic Med, 2017 Sep;5:553-569). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this alteration remains unclear. -
This missense variant replaces aspartic acid with glycine at codon 803 of the MSH6 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). A functional study has reported that this variant protein has reduced nucleotide exchange and ATPase activities (PMID: 18790734). This variant has been reported in individuals affected with colorectal, breast, pancreatic cancer or glioblastoma multiforme (PMID: 10537275, 25186627, 25479140, 26689913, 31391288, 31428572, 33471991), as well as in several healthy controls in a breast cancer case-control study (PMID: 33471991). This variant has been identified in 22/282092 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
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BS1, BP4 c.2408A>G located in exon 4 of the MSH6 gene, is predicted to result in the substitution of aspartic acid by glycine at codon 803; p.(Asp803Gly). This variant is found in 82/1614124 alleles at a frequency of 0,0051% in the gnomAD v4 database, with a filter allele frequency of 0.026% (South Asian dataset) (BS1). Computational tools for this variant suggests no significant impact on splicing (SpliceAI) or protein function (MAPP+PolyPhen-2 prior probability for pathogenicity: 0.007 (BP4). In contrast, a functional study has reported that this variant protein has reduced nucleotide exchange and ATPase activities (PMID: 18790734). The variant has been reported in ClinVar (12x uncertain significance, 2x likely benign, 2x benign), LOVD (2x uncertain significance, 3x not classified) and in the InSiGHT database as Class 3: uncertain (Insufficient evidence). Based on currently available information, and taking into account the apparent discrepancies, the variant c.2408A>G is classified as an uncertain significance variant according to ClinGen-Insight_ACMG_Specifications_MSH6_v1.0.0. -
Lynch syndrome 5 Uncertain:3Benign:1
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The MSH6 c.2408A>G (p.Asp803Gly) missense change has a maximum founder subpopulation frequency of 0.08% and a maximum non-founder subpopulation frequency of 0.03% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/). The in silico tool REVEL is inconclusive about a pathogenic or benign effect of this variant on protein function. This variant has been reported in an individual with colorectal cancer (PMID: 31428572). In summary, the evidence currently available is insufficient to determine the clinical significance of this variant. It has therefore been classified as of uncertain significance. -
This variant is considered 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]. 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. -
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not provided Uncertain:2
In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in individuals with colorectal and other cancers (PMID: 10537275, 25479140, 26689913, 25186627, 28944238, 31428572); This variant is associated with the following publications: (PMID: 22788692, 22290698, 25637381, 10537275, 23621914, 19766128, 27363283, 26689913, 11900875, 25479140, 25186627, 26206375, 28944238, 31391288, 34445333, 33471991, 24393486, 31428572, 17531815, 21120944, 36922933, 18790734) -
The MSH6 c.2408A>G (p.Asp803Gly) variant has been reported in the published literature in individuals with colorectal cancer (PMIDs: 10537275 (1999) and 31428572 (2019)), breast cancer (PMID: 25186627 (2015)), pancreatic cancer (PMID: 25479140 (2015)), and glioblastoma multiforme (PMID: 26689913 (2015)). This variant was also found in individuals with breast cancer well as in reportedly healthy individuals in a large scale breast cancer association study (PMID: 33471991 (2021), see also LOVD (http://databases.lovd.nl/shared/genes/MSH6)). A functional study indicated that the variant may uncouple nucleotide processing and DNA binding (PMID: 18790734 (2008)). The frequency of this variant in the general population, 0.00077 (8/10354 chromosomes in Ashkenazi Jewish subpopulation (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is higher than would generally be expected for pathogenic variants in this gene. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded conflicting predictions that this variant is deleterious or benign. Based on the available information, we are unable to determine the clinical significance of this variant. -
not specified Uncertain:1Benign:1
Variant identified in a genome or exome case(s) and assessed due to predicted null impact of the variant or pathogenic assertions in the literature or databases. Disclaimer: This variant has not undergone full assessment. The following are preliminary notes: Classified as VUS by expert panel in 2013; no new evidence supporting pathogenicity since then -
Variant summary: MSH6 c.2408A>G (p.Asp803Gly) results in a non-conservative amino acid change located in the DNA mismatch repair protein MutS, core 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 5.1e-05 in 1614502 control chromosomes, predominantly at a frequency of 0.00035 within the South Asian subpopulation in the gnomAD database. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 2 fold of the estimated maximal expected allele frequency for a pathogenic variant in MSH6 causing Hereditary Nonpolyposis Colorectal Cancer phenotype (0.00014), strongly suggesting that the variant is a benign polymorphism found primarily in populations of South Asian origin. c.2408A>G has been reported in the literature in cohorts of individuals affected with various cancers such as the Ontario Pancreas cancer study cohort, the TGCA cohort, breast and colorectal cancer (example, Grant_2015, Kolodner_1999, Tung_2015, Lu_2015, Zhunssova_2019). These report(s) do not provide unequivocal conclusions about association of the variant with Hereditary Nonpolyposis Colorectal Cancer/Lynch syndrome. A recent study testing MMR pathogenic variant association with MSI/IHC status, and estimated likelihood ratios to compute a tumor characteristic likelihood ratio (TCLR) included this variant. Predictive performance of TCLR in combination with in silico predictors, and a multifactorial variant prediction (MVP) model that included allele frequency, co-occurrence, co-segregation, and clinical and family history information resulted in its classification as likely benign (Li_2020). At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect affect the ability to be cross linked to ATP, suggesting the mutant appears to uncouple the mismatch binding and ATP hydrolysis activities of the MSH2-MSH6 heterodimer (Cyr_2008). However, the in-vivo implications of this finding are unclear. The following publications have been ascertained in the context of this evaluation (PMID: 10537275, 18790734, 22290698, 23621914, 11900875, 25479140, 25186627, 26689913, 19766128, 31428572, 31391288). Eleven submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 and classified as VUS (n=9) and benign/likely benign (n=2). Based on the evidence outlined above, the variant was classified as likely benign. -
Colorectal cancer Uncertain:1
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Lynch syndrome Uncertain:1
This missense variant replaces aspartic acid with glycine at codon 803 of the MSH6 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). A functional study has reported that this variant protein has reduced nucleotide exchange and ATPase activities (PMID: 18790734). This variant has been reported in individuals affected with colorectal, breast, pancreatic cancer or glioblastoma multiforme (PMID: 10537275, 25186627, 25479140, 26689913, 31391288, 31428572, 33471991), as well as in several healthy controls in a breast cancer case-control study (PMID: 33471991). This variant has been identified in 22/282092 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Malignant tumor of breast Uncertain:1
The MSH6 p.Asp803Gly variant was identified in 4 of 13218 proband chromosomes (frequency: 0.0003) from individuals or families with pancreatic cancer, colorectal or breast cancer, and glioblastoma (Grant 2015, Kolodner 1999, Lu 2015, Tung 2015). The variant was also identified in dbSNP (ID: rs63751450) as "With Uncertain significance allele", ClinVar (classified as uncertain significance by InSight, Ambry Genetics, GeneDx, Invitae, Counsyl, Color Genomics, and four clinical laboratories), Mismatch Repair Genes Variant Database, and in Insight Hereditary Tumors Database (2x as uncertain). The variant was not identified in COGR, Cosmic, MutDB, UMD-LSDB, or Zhejiang University databases. The variant was identified in control databases in 23 of 276376 chromosomes at a frequency of 0.00008 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: Other in 1 of 6458 chromosomes (freq: 0.0002), European in 4 of 125932 chromosomes (freq: 0.00003), Ashkenazi Jewish in 9 of 10136 chromosomes (freq: 0.0009), and South Asian in 9 of 30782 chromosomes (freq: 0.0003), but not in the African, Latino, East Asian, or Finnish populations. The p.Asp803 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 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. -
Endometrial carcinoma Uncertain:1
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Endometrial carcinoma;C1833477:Lynch syndrome 5;C5436807:Mismatch repair cancer syndrome 3 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