Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM4
The NM_000535.7(PMS2):c.2588G>T(p.Ter863Leuext*?) variant causes a stop lost change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).
PMS2 (HGNC:9122): (PMS1 homolog 2, mismatch repair system component) The protein encoded by this gene is a key component of the mismatch repair system that functions to correct DNA mismatches and small insertions and deletions that can occur during DNA replication and homologous recombination. This protein forms heterodimers with the gene product of the mutL homolog 1 (MLH1) gene to form the MutL-alpha heterodimer. The MutL-alpha heterodimer possesses an endonucleolytic activity that is activated following recognition of mismatches and insertion/deletion loops by the MutS-alpha and MutS-beta heterodimers, and is necessary for removal of the mismatched DNA. There is a DQHA(X)2E(X)4E motif found at the C-terminus of the protein encoded by this gene that forms part of the active site of the nuclease. Mutations in this gene have been associated with hereditary nonpolyposis colorectal cancer (HNPCC; also known as Lynch syndrome) and Turcot syndrome. [provided by RefSeq, Apr 2016]
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This variant is not present in the population databases (ExAC no frequency), however, the frequency data is considered unreliable due to the presence of a pseudogene that has strong homology to this region. This sequence change disrupts the translational stop signal of the PMS2 mRNA. It is expected to extend the length of the PMS2 protein by 2 additional amino acid residues. This variant has not been reported in the literature in individuals with PMS2-related disease. Experimental studies and prediction algorithms are not available for this variant, and the functional significance of the additional amino acids are currently unknown. 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. -