rs587779262
Variant summary
Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1PM2PM5PP3PP5
The NM_000179.3(MSH6):c.3437A>C(p.Gln1146Pro) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 14/24 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. 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. Q1146R) has been classified as Uncertain significance.
Frequency
Consequence
NM_000179.3 missense, splice_region
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: Likely_pathogenic. The variant received 8 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome Cov.: 33
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Pathogenic:1
The p.Q1146P pathogenic mutation (also known as c.3437A>C), located in coding exon 5 of the MSH6 gene, results from an A to C substitution at nucleotide position 3437. The glutamine at codon 1146 is replaced by proline, an amino acid with similar properties. This alteration has been observed in multiple individuals whose Lynch-related tumors demonstrated high microsatellite instability and/or loss of MSH6 expression on immunohistochemistry (IHC) and in multiple families meeting Amsterdam criteria (Ambry internal data). Based on internal structural analysis using published crystal structures, Q1146P is disruptive to the region near the ATP-binding site (Warren JJ et al. Mol Cell. 2007 May;26:579-92). 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 supporting evidence, this alteration is interpreted as a disease-causing mutation. -
not provided Uncertain:1
The MSH6 p.Gln1146Pro variant was not identified in the literature nor was it identified in the GeneInsight-COGR, Cosmic, MutDB, UMD-LSDB, Zhejiang Colon Cancer Database, or Mismatch Repair Genes Variant database. The variant was identified in the dbSNP as “with uncertain significance allele”. In addition, the variant was identified in ClinVar and Clinvitae by InSIGHT as uncertain significance; in Insight Colon Cancer Gene Variant Database as Class 3 constitutional with no other information provided; and in Insight Hereditary Tumors Database as Germline inherited with unknown allele. The variant was not identified in the 1000 Genomes Project, the NHLBI GO Exome Sequencing Project or the Exome Aggregation Consortium (August 8th 2016) control databases. The p.Gln1146 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 p.Gln1146Pro variant occurs in the second last base of the exon. This position has been shown to be part of the splicing consensus sequence and variants involving this position sometimes affect splicing. In silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predicts a greater than 10% difference in splicing in 2 of 5 programs, however, this information is not very predictive of pathogenicity. The variant is located with the DNA mismatch repair protein MutS, C-terminal P-loop containing nucleoside triphosphate hydrolase DNA mismatch repair protein MSH6 functional domain, the clinical significance of which is uncertain. 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. -
Hereditary nonpolyposis colorectal neoplasms Uncertain:1
This sequence change replaces glutamine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 1146 of the MSH6 protein (p.Gln1146Pro). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with colon cancer (PMID: 21520333). ClinVar contains an entry for this variant (Variation ID: 89383). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at