Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4BP6
The NM_000249.4(MLH1):c.676C>A(p.Arg226Arg) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
MLH1 (HGNC:7127): (mutL homolog 1) The protein encoded by this gene can heterodimerize with mismatch repair endonuclease PMS2 to form MutL alpha, part of the DNA mismatch repair system. When MutL alpha is bound by MutS beta and some accessory proteins, the PMS2 subunit of MutL alpha introduces a single-strand break near DNA mismatches, providing an entry point for exonuclease degradation. The encoded protein is also involved in DNA damage signaling and can heterodimerize with DNA mismatch repair protein MLH3 to form MutL gamma, which is involved in meiosis. This gene was identified as a locus frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). [provided by RefSeq, Aug 2017]
Verdict is Uncertain_significance. Variant got 0 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.17).
BP6
Variant 3-37012098-C-A is Benign according to our data. Variant chr3-37012098-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 629190.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with MLH1-related conditions. ClinVar contains an entry for this variant (Variation ID: 629190). This variant is not present in population databases (ExAC no frequency). This sequence change affects codon 226 of the MLH1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MLH1 protein. -
Colorectal cancer, hereditary nonpolyposis, type 2 Benign:1
Nov 20, 2024
Myriad Genetics, Inc.
Significance: Benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This variant is considered benign. This variant is a silent/synonymous amino acid change and it is not expected to impact splicing. -
Hereditary cancer-predisposing syndrome Benign:1
Sep 05, 2018
Color Diagnostics, LLC DBA Color Health
Significance: Likely benign
Review Status: criteria provided, single submitter