Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PP3_Moderate
The NM_000535.7(PMS2):c.206C>T(p.Ser69Leu) variant causes a missense 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. 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 denoted PMS2 c.206C>T at the cDNA level, p.Ser69Leu (S69L) at the protein level, and results in the change of a Serine to a Leucine (TCA>TTA). This variant has been observed as a somatic variant in a pancreatic tumor (COSMIC), but has not been reported as a germline variant. PMS2 Ser69Leu was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Since Serine and Leucine differ in polarity, charge, size or other properties, this is considered a non-conservative amino acid substitution. PMS2 Ser69Leu occurs at a position that is highly conserved across species and is located in the N-terminal ATPase domain (Fukui 2011). In silico analyses predict that this variant is probably damaging to protein structure and function. Based on currently available information, it is unclear whether PMS2 Ser69Leu is pathogenic or benign. We consider it to be a variant of uncertain significance. -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces serine, which is neutral and polar, with leucine, which is neutral and non-polar, at codon 69 of the PMS2 protein (p.Ser69Leu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with PMS2-related conditions. ClinVar contains an entry for this variant (Variation ID: 182807). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt PMS2 protein function with a positive predictive value of 80%. 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. -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The p.S69L variant (also known as c.206C>T), located in coding exon 3 of the PMS2 gene, results from a C to T substitution at nucleotide position 206. The serine at codon 69 is replaced by leucine, an amino acid with dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -