NM_000179.3:c.1730G>A
Variant summary
Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM1PP3
The NM_000179.3(MSH6):c.1730G>A(p.Arg577His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000756 in 1,614,154 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. R577G) has been classified as Uncertain significance.
Frequency
Consequence
NM_000179.3 missense
Scores
Clinical Significance
Conservation
Publications
- intellectual developmental disorder with dysmorphic facies and behavioral abnormalitiesInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
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ACMG classification
Our verdict: Uncertain_significance. The variant received 3 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000920 AC: 14AN: 152150Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000400 AC: 10AN: 250236 AF XY: 0.0000442 show subpopulations
GnomAD4 exome AF: 0.0000739 AC: 108AN: 1461886Hom.: 0 Cov.: 34 AF XY: 0.0000591 AC XY: 43AN XY: 727244 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000919 AC: 14AN: 152268Hom.: 0 Cov.: 32 AF XY: 0.0000672 AC XY: 5AN XY: 74446 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:5
In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in individuals with pancreatic, endometrial, breast, and other cancers (PMID: 27449771, 27443514, 26689913, 32885271, 33606809, 35264596, 35534704); This variant is associated with the following publications: (PMID: 26510091, 34011629, 31253177, 24728327, 23621914, 26546047, 27449771, 27443514, 26689913, 25363768, 31104363, 26436109, 31785789, Giacomazzi2022[preprint], 35982159, 35982160, 32885271, 33606809, 25085752, 23729658, 35264596, 21120944, 17531815, 39858023, 35534704, 28867142) -
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The MSH6 c.1730G>A (p.Arg577His) variant has been reported in the published literature in individuals affected with breast cancer (PMID: 32885271 (2021), 33471991 (2021), see also LOVD (https://databases.lovd.nl/shared/variants/MSH6), 33606809 (2021), and 35264596 (2022)), thyroid cancer (PMID: 35534704 (2022)), endometrial cancer (PMID: 27443514 (2016)), pancreatic cancer (PMID: 27449771 (2016)), tubulovillous adenomas (PMID: 26436109 (2015)), and autism (PMID: 25363768 (2014), 31785789 (2019), 34011629 (2021)). This variant is also found in reportedly healthy individuals (PMID: 33471991 (2021), see also LOVD (https://databases.lovd.nl/shared/variants/MSH6)). The frequency of this variant in the general population, 0.000087 (3/34586 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. 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 benign or damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -
Lynch syndrome 5 Uncertain:2Benign:1
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]. -
The MSH6 c.1730G>A (p.Arg577His) missense change has a maximum subpopulation frequency of 0.0087% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/). The in silico tool REVEL predicts a deleterious effect on protein function, but this prediction has not been confirmed by functional studies. This variant has been reported in individuals affected with endometrial, pancreatic, ovarian, and breast cancer (PMID: 26689913, 27443514, 27449771, 32885271, 33606809), and it has also been observed in an unaffected individual (PMID: 24728327). 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 submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
Hereditary cancer-predisposing syndrome Uncertain:2
This missense variant replaces arginine with histidine at codon 577 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). To our knowledge, functional studies have not been performed for this variant. This variant has been reported in individuals affected with endometrial, pancreatic and breast cancer (PMID: 26689913, 27443514, 27449771, 32885271, 33606809, 35264596) and an unaffected individual (PMID: 24728327). This variant has been identified in 10/250236 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. -
The p.R577H variant (also known as c.1730G>A), located in coding exon 4 of the MSH6 gene, results from a G to A substitution at nucleotide position 1730. The arginine at codon 577 is replaced by histidine, an amino acid with highly similar properties. This alteration has been reported in cohorts of breast and endometrial cancer patients (Lu C et al. Nat Commun. 2015 Dec 22;6:10086; Ring KL et al. Mod Pathol. 2016 Nov;29(11):1381-1389; Sandoval RL et al. PLoS One, 2021 Feb;16:e0247363; erner-Ellis J et al. J Cancer Res Clin Oncol, 2021 Mar;147:871-879; Guindalini RSC et al. Sci Rep, 2022 Mar;12:4190). However, this variant was also identified in a cohort of 681 ancestrally diverse, healthy subjects under the age of 50 (Bodian DL et al. PLoS ONE. 2014 Apr;9:e94554). This alteration (designated as rs376220212) also co-occurred with an MSH2 missense alteration in one of 25 asymptomatic adults undergoing whole exome sequencing; this individual was found to have two tubulovillous adenomas at age 50 (Pillar N et al. Mol. Genet. Genomic Med. 2015 Sep;3:433-9). The p.R577H variant was classified as deleterious by authors who identified it in a CDKN2A mutation positive patient with pancreatic cancer and in 0 of 1001 controls. This determination, however, was made based on the meta likelihood ratio prediction tool incorporating in silico algorithms and allele frequency only (Yang XR et al. Hum. Genet. 2016 Nov;135:1241-1249). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -
Endometrial carcinoma Uncertain:2
ACMG classification criteria: PM2 supporting -
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not specified Uncertain:1Other:1
Variant summary: MSH6 c.1730G>A (p.Arg577His) results in a non-conservative amino acid change in 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 4e-05 in 250236 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in MSH6 causing Lynch Syndrome (4e-05 vs 0.00014), allowing no conclusion about variant significance. c.1730G>A has been reported in the literature in individuals affected with tubulovillous adenomas, endometrial carcinoma or pancreatic cancer (Pillar_2015, Ring_2016, Yang_2016). These reports do not provide unequivocal conclusions about association of the variant with Lynch Syndrome. Co-occurrences with other pathogenic variant(s) have been reported (MSH6 c.2677_2678delCT, p.Leu893AlafsX6), providing supporting evidence for a benign role. Six 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 uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
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Lynch-like syndrome Pathogenic:1
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Carcinoma of colon Uncertain:1
The MSH6 p.Arg577His variant was identified in a study of 114 cancer susceptibility genes, in individuals with 12 different cancer types, in 1 of 8068 proband chromosomes (frequency: 0.0001) from individuals or families with lung adenocarcinoma (Lu 2015) and was present in 1 of 1362 control chromosomes (frequency: 0.0007) from healthy individuals (Bodian 2014). The variant was also identified in dbSBP (ID: rs376220212) as “With Uncertain significance allele,” ClinVar (as uncertain significance), Clinvitae (as uncertain significance), Cosmic, UMD-LSDB (co-occurring with a pathogenic MSH6 variant p.Leu893AlafsX6), as well as in our laboratory co-occurring with a pathogenic APC variant (p.Tyr1027IlefsX10), increasing the likelihood that the p.Arg577His variant does not have clinical significance. The variant was not identified in MutDB, Insight Colon Cancer Gene Variant Database, Zhejiang Colon Cancer Database, Mismatch Repair Genes Variant Database, and Insight Hereditary Tumors Database. The variant was identified in control databases in 10 of 245960 chromosomes at a frequency of 0.000041 in the following populations: African in 1 of 15286 chromosomes (freq. 0.000065), Latino in 3 of 33578 chromosomes (freq. 0.000089), and European (Non-Finnish) in 6 of 111440 chromosomes (freq. 0.00005) populations, increasing the likelihood that this may be a low frequency benign variant in certain populations of origin (Genome Aggregation Consortium Feb 27, 2017). The p.Arg577His residue is conserved across mammals and other organisms, and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the 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, HumanSpliceFinder) do not predict a difference in splicing. The variant is located with the DNA mismatch repair protein MutS, connector domain DNA mismatch repair protein MSH6 functional domain(s) increasing the likelihood that it may have clinical significance. 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. -
Lynch syndrome Uncertain:1
This missense variant replaces arginine with histidine at codon 577 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). To our knowledge, functional studies have not been performed for this variant. This variant has been reported in individuals affected with endometrial, pancreatic and breast cancer (PMID: 26689913, 27443514, 27449771, 32885271, 33606809, 35264596) and an unaffected individual (PMID: 24728327). This variant has been identified in 10/250236 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. -
Hereditary nonpolyposis colon cancer Benign:1
This variant is considered likely benign or benign based on one or more of the following: it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease, and/or has normal protein function, and/or has lack of segregation with disease, and/or has been detected in co-occurrence with known pathogenic variant, and/or has lack of disease association in case-control studies, and/or is located in a region inconsistent with a known cause of pathogenicity. -
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