Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1PM2BP4
The NM_000535.7(PMS2):c.1733G>T(p.Arg578Leu) variant causes a missense 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. 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]
Verdict is Uncertain_significance. Variant got 3 ACMG points.
PM1
In a mutagenesis_site Affects binding to importins alpha, including KPNA2, hence may affect import to the nucleus. (size 0) in uniprot entity PMS2_HUMAN
PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.34398723).
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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Apr 19, 2023
Ambry Genetics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The p.R578L variant (also known as c.1733G>T), located in coding exon 11 of the PMS2 gene, results from a G to T substitution at nucleotide position 1733. The arginine at codon 578 is replaced by leucine, an amino acid with dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
not provided Uncertain:1
Oct 11, 2016
GeneDx
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This variant is denoted PMS2 c.1733G>T at the cDNA level, p.Arg578Leu (R578L) at the protein level, and results in the change of an Arginine to a Leucine (CGT>CTT). This variant has not, to our knowledge, been reported as a germline pathogenic or benign variant; however, it has been reported by Balogh et al. (2006) as a somatic variant observed in breast tumors. PMS2 Arg578Leu was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Arginine and Leucine differ in polarity, charge, size or other properties, this is considered a non-conservative amino acid substitution. PMS2 Arg578Leu occurs at a position that is not conserved and is not located in a known functional domain (Guarne 2001, Fukui 2011). In silico analyses predict that this variant is probably damaging to protein structure and function. Based on currently available evidence, it is unclear whether PMS2 Arg578Leu is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces arginine with leucine at codon 578 of the PMS2 protein (p.Arg578Leu). The arginine residue is moderately conserved and there is a moderate physicochemical difference between arginine and leucine. This variant is not present in population databases (ExAC 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: 421090). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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. -