2-47803601-G-A
Variant summary
Our verdict is Benign. Variant got -14 ACMG points: 0P and 14B. BP4_StrongBP6BP7BS1BS2
The NM_000179.3(MSH6):c.3354G>A(p.Glu1118Glu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000233 in 1,614,190 control chromosomes in the GnomAD database, including 6 homozygotes. 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 synonymous
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -14 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000138 AC: 21AN: 152188Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000398 AC: 100AN: 251408Hom.: 1 AF XY: 0.000589 AC XY: 80AN XY: 135864
GnomAD4 exome AF: 0.000243 AC: 355AN: 1461884Hom.: 6 Cov.: 33 AF XY: 0.000363 AC XY: 264AN XY: 727244
GnomAD4 genome AF: 0.000138 AC: 21AN: 152306Hom.: 0 Cov.: 32 AF XY: 0.000242 AC XY: 18AN XY: 74472
ClinVar
Submissions by phenotype
not specified Benign:4
Variant summary: MSH6 c.3354G>A alters a non-conserved nucleotide resulting in a synonymous change. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00043 in 246174 control chromosomes, predominantly at a frequency of 0.0034 within the South Asian subpopulation in the gnomAD database, including 3 homozygotes. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 23.93 fold of the estimated maximal expected allele frequency for a pathogenic variant in MSH6 causing Lynch Syndrome phenotype (0.00014), strongly suggesting that the variant is a benign polymorphism found primarily in populations of South Asian origin. To our knowledge, no occurrence of c.3354G>A in individuals affected with Lynch Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -
The MSH6 p.Glu1118= variant was not identified in the literature nor was it identified in the following databases: GeneInsight-COGR, Cosmic, MutDB, UMD-LSDB, Insight Colon Cancer Gene Variant Database, Zhejiang Colon Cancer Database, Mismatch Repair Genes Variant Database, or Insight Hereditary Tumors Database. The variant was identified in dbSNP (ID: rs35642130) “With Likely benign allele”, ClinVar (classified benign by Invitae, GeneDx and likely benign by Ambry Genetics), Clinvitae (3x), and in control databases in 106 (3 homozygous) of 246174 chromosomes at a frequency of 0.0004 increasing the likelihood this could be a low frequency benign variant (Genome Aggregation Database Feb 27, 2017). Breakdown of the observations by population include European Non-Finnish in 1 of 111648 chromosomes (freq: 0.000009), and South Asian in 105 (3 homozygous) of 30782 chromosomes (freq: 0.003), while not observed in the African, Other, Latino, Ashkenazi Jewish, East Asian, or European Finnish populations. The p.Glu1118= variant is not expected to have clinical significance because it does not result in a change of amino acid and is not located in a known consensus splice site, with 2 of 5 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predicting a greater than 10% difference in splicing; this is not very predictive of pathogenicity. In summary, based on the above information this variant meets our laboratory's criteria to be classified as benign. -
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This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Hereditary cancer-predisposing syndrome Benign:3
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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 5 Uncertain:1Benign:1
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
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Lynch syndrome Benign:1
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not provided 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