rs561198849
Variant summary
Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM1PP3
The NM_000179.3(MSH6):c.2291C>A(p.Thr764Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000105 in 1,614,040 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a benign 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. T764S) has been classified as Likely benign.
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
Genome browser will be placed here
ACMG classification
Our verdict: Uncertain_significance. The variant received 3 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| MSH6 | NM_000179.3 | c.2291C>A | p.Thr764Asn | missense_variant | Exon 4 of 10 | ENST00000234420.11 | NP_000170.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| MSH6 | ENST00000234420.11 | c.2291C>A | p.Thr764Asn | missense_variant | Exon 4 of 10 | 1 | NM_000179.3 | ENSP00000234420.5 |
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152164Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000159 AC: 4AN: 251148 AF XY: 0.0000295 show subpopulations
GnomAD4 exome AF: 0.0000103 AC: 15AN: 1461876Hom.: 0 Cov.: 34 AF XY: 0.0000138 AC XY: 10AN XY: 727238 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152164Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74324 show subpopulations
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Uncertain:3
- -
This missense variant replaces threonine with asparagine at codon 764 of the MSH6 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual with colorectal cancer, however, this individual also carried a pathogenic variant in the MLH1 gene that could explain the observed phenotype (PMID: 15713769). This variant has also been reported in an individual affected with hereditary breast cancer (PMID: 32547938). This variant has been identified in 5/282546 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.T764N variant (also known as c.2291C>A), located in coding exon 4 of the MSH6 gene, results from a C to A substitution at nucleotide position 2291. The threonine at codon 764 is replaced by asparagine, an amino acid with similar properties. This variant has been identified in a proband(s) who met Amsterdam I/II criteria for Lynch syndrome and tumor demonstrated high microsatellite instability; however, this variant was seen in conjunction with a pathogenic MLH1 variant (Casey G et al. JAMA 2005 Feb;293(7):799-809). This variant was also reported in one of 711 Russian individuals diagnosed with breast cancer but was absent from 492 healthy controls. The patient with this variant also reportedly carried a BRCA2 pathogenic mutation (Nikitin AG et al. Front Oncol, 2020 May;10:666). 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 variant remains unclear. -
Lynch syndrome 5 Uncertain:2
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. -
This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -
not provided Uncertain:2
Not observed at a significant frequency in large population cohorts (Lek 2016); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in individuals with a personal or family history including breast cancer (Nikitin 2020); Observed in an individual in published literature (Casey 2005) who had a different genetic etiology for colorectal cancer; This variant is associated with the following publications: (PMID: 15713769, 23621914, 32547938) -
- -
not specified Uncertain:1
Variant summary: MSH6 c.2291C>A (p.Thr764Asn) results in a non-conservative amino acid change located in the DNA mismatch repair protein MutS, core domain (IPR007696) 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 1.6e-05 in 251148 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.2291C>A has been reported in the literature in individuals affected with colorectal, breast, or pancreatic cancer without stong evidence for causality (Casey_2005, Nikitin_2020, Emelyanova_2024). These reports do not provide unequivocal conclusions about association of the variant with Hereditary Nonpolyposis Colorectal Cancer. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 15713769, 32547938, 38893230). ClinVar contains an entry for this variant (Variation ID: 184444). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Lynch syndrome Uncertain:1
This missense variant replaces threonine with asparagine at codon 764 of the MSH6 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual with colorectal cancer, however, this individual also carried a pathogenic variant in the MLH1 gene that could explain the observed phenotype (PMID: 15713769). This variant has also been reported in an individual affected with hereditary breast cancer (PMID: 32547938). This variant has been identified in 5/282546 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. -
Endometrial carcinoma Uncertain:1
- -
Hereditary nonpolyposis colorectal neoplasms Benign:1
- -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at