Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PM2
The ENST00000234420.11(MSH6):āc.3598A>Gā(p.Ile1200Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,666 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. I1200M) has been classified as Uncertain significance.
MSH6 (HGNC:7329): (mutS homolog 6) This gene encodes a member of the DNA mismatch repair MutS family. In E. coli, the MutS protein helps in the recognition of mismatched nucleotides prior to their repair. A highly conserved region of approximately 150 aa, called the Walker-A adenine nucleotide binding motif, exists in MutS homologs. The encoded protein heterodimerizes with MSH2 to form a mismatch recognition complex that functions as a bidirectional molecular switch that exchanges ADP and ATP as DNA mismatches are bound and dissociated. Mutations in this gene may be associated with hereditary nonpolyposis colon cancer, colorectal cancer, and endometrial cancer. Transcripts variants encoding different isoforms have been described. [provided by RefSeq, Jul 2013]
FBXO11 (HGNC:13590): (F-box protein 11) This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxs class. It can function as an arginine methyltransferase that symmetrically dimethylates arginine residues, and it acts as an adaptor protein to mediate the neddylation of p53, which leads to the suppression of p53 function. This gene is known to be down-regulated in melanocytes from patients with vitiligo, a skin disorder that results in depigmentation. Polymorphisms in this gene are associated with chronic otitis media with effusion and recurrent otitis media (COME/ROM), a hearing loss disorder, and the knockout of the homologous mouse gene results in the deaf mouse mutant Jeff (Jf), a single gene model of otitis media. Alternatively spliced transcript variants encoding distinct isoforms have been identified for this gene. [provided by RefSeq, Jun 2010]
Verdict is Uncertain_significance. Variant got 4 ACMG points.
PM1
In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 16 uncertain in ENST00000234420.11
PM2
Very rare variant in population databases, with high coverage;
Uncertain significance, criteria provided, single submitter
clinical testing
Mendelics
Jul 02, 2018
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Uncertain significance, criteria provided, single submitter
clinical testing
All of Us Research Program, National Institutes of Health
Jun 09, 2024
This missense variant replaces isoleucine with valine at codon 1200 of the MSH6 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with MSH6-related disorders in the literature. This variant has been identified in 2/251442 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. -
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Jan 13, 2023
The p.I1200V variant (also known as c.3598A>G), located in coding exon 7 of the MSH6 gene, results from an A to G substitution at nucleotide position 3598. The isoleucine at codon 1200 is replaced by valine, an amino acid with highly similar properties. 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. -
Uncertain significance, criteria provided, single submitter
clinical testing
Color Diagnostics, LLC DBA Color Health
Feb 01, 2019
- -
Lynch syndrome 5 Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein
Uncertain significance, criteria provided, single submitter
clinical testing
GeneDx
Aug 22, 2022
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter 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) -
Endometrial carcinoma Uncertain:1
Uncertain significance, criteria provided, single submitter