rs876660882
Variant summary
Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PM5
The NM_000179.3(MSH6):c.3607C>A(p.His1203Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000013 in 1,613,212 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. H1203P) has been classified as Likely pathogenic.
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 4 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000658 AC: 1AN: 151886Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.00000398 AC: 1AN: 251442 AF XY: 0.00000736 show subpopulations
GnomAD4 exome AF: 0.0000137 AC: 20AN: 1461326Hom.: 0 Cov.: 33 AF XY: 0.0000165 AC XY: 12AN XY: 727036 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000658 AC: 1AN: 151886Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0AN XY: 74148 show subpopulations ⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
Age Distribution
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Uncertain:3
This missense variant replaces histidine with asparagine at codon 1203 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 reported for this variant. This variant has been reported in an individual affected with breast cancer (PMID: 25186627). This variant has been identified in 2/282784 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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The p.H1203N variant (also known as c.3607C>A), located in coding exon 7 of the MSH6 gene, results from a C to A substitution at nucleotide position 3607. The histidine at codon 1203 is replaced by asparagine, an amino acid with similar properties. This alteration was detected on a 25-gene panel test in a woman who was diagnosed with breast cancer before age 50 (Tung N et al. Cancer. 2015 Jan;121:25-33). This alteration was also detected in the germline of a patient diagnosed with an MLH1/PMS2-deficient colon cancer at age 50; the tumor was identified to have double somatic MLH1 mutations (Pearlman R et al. J Med Genet. 2019 07;56:462-470). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Endometrial carcinoma;C1833477:Lynch syndrome 5;C5436807:Mismatch repair cancer syndrome 3 Uncertain:2
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not provided Uncertain:2
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 17531815, 21120944) -
In the published literature, this variant has been reported in individuals with breast cancer (PMID: 25186627 (2015)), and colorectal cancer (PMID: 30877237 (2019)). The frequency of this variant in the general population, 0.0000071 (2/282784 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 Uncertain:1
This missense variant replaces histidine with asparagine at codon 1203 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 reported for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 2/282784 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
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Lynch syndrome 5 Benign: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]. -
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