2-47799989-T-C
Variant summary
Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_000179.3(MSH6):āc.2006T>Cā(p.Ile669Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000013 in 1,614,074 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I669V) 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
Genome browser will be placed here
ACMG classification
Our verdict: Likely_benign. The variant received -2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152076Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000398 AC: 10AN: 251038 AF XY: 0.0000369 show subpopulations
GnomAD4 exome AF: 0.0000116 AC: 17AN: 1461880Hom.: 0 Cov.: 34 AF XY: 0.0000124 AC XY: 9AN XY: 727240 show subpopulations
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152194Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1AN XY: 74402 show subpopulations
ClinVar
Submissions by phenotype
not provided Uncertain:3
- -
In silico analysis supports that this missense variant does not alter protein structure/function; Observed in individuals with colorectal or other cancers (Soares et al., 2017; Schneider et al., 2018; Greenberg et al., 2020; Li et al., 2020); This variant is associated with the following publications: (PMID: 23621914, 28932927, 26333163, 29575718, 31927803, 17531815, 21120944, 22290698, 31391288) -
The MSH6 c.2006T>C (p.Ile669Thr) variant has been reported in the published literature in individuals affected with colorectal cancer (PMIDs: 31927803 (2020), 29575718 (2018)), Lynch syndrome (PMID: 28932927 (2018)), breast cancer (PMID: 35534704 (2022)), and other unspecified cancers (PMID: 31391288 (2020)). In a large scale breast cancer association study, this variant has been observed in 1 breast cancer case and 1 reportedly healthy individual (PMID: 33471991 (2021), see also LOVD (http://databases.lovd.nl/shared)). The frequency of this variant in the general population, 0.00017 (6/34582 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 deleterious or benign. Based on the available information, we are unable to determine the clinical significance of this variant. -
Hereditary cancer-predisposing syndrome Uncertain:3
This missense variant replaces isoleucine with threonine at codon 669 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 individuals affected with or suspected of having Lynch syndrome (PMID: 28932927, 29575718, 31391288, 31927803). This variant has also been identified in 10/251038 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.I669T variant (also known as c.2006T>C), located in coding exon 4 of the MSH6 gene, results from a T to C substitution at nucleotide position 2006. The isoleucine at codon 669 is replaced by threonine, an amino acid with similar properties. This variant has been reported in Brazilian individuals fulfilling either Bethesda or Amsterdam criteria for Lynch syndrome (Soares BL et al. Fam. Cancer 2017 Sep https://doi.org/10.1007/s10689-017-0043-5; Schneider NB et al. Cancer Med, 2018 May;7:2078-2088). This amino acid position is poorly 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. -
- -
Lynch syndrome 5 Uncertain:1Benign:1
This variant is considered likely benign. Homozygosity for this variant has been confirmed in one or more individuals lacking clinical features consistent with gene-specific recessive disease, indicating that this variant is unlikely to be pathogenic. -
- -
not specified Uncertain:1
Variant summary: MSH6 c.2006T>C (p.Ile669Thr) results in a non-conservative amino acid change located in the connector domain (IPR007860) of the encoded protein sequence. Three 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 251038 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in MSH6 causing Hereditary Nonpolyposis Colorectal Cancer (4e-05 vs 0.00014), allowing no conclusion about variant significance. c.2006T>C has been reported in the literature in individuals affected with Hereditary Nonpolyposis Colorectal Cancer. 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. Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation (likely benign n=1, VUS n=5). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Endometrial carcinoma;C1833477:Lynch syndrome 5;C5436807:Mismatch repair cancer syndrome 3 Uncertain:1
- -
Lynch syndrome Uncertain:1
This missense variant replaces isoleucine with threonine at codon 669 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 individuals affected with or suspected of having Lynch syndrome (PMID: 28932927, 29575718, 31391288, 31927803), or breast cancer (DOI: 10.1101/2021.04.15.21255554). This variant has also been identified in 10/251038 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