Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2BP6
The NM_000535.7(PMS2):c.779_780delCCinsTG(p.Ser260Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. S260C) has been classified 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]
Our verdict: Uncertain_significance. The variant received 1 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
BP6
Variant 7-5997349-GG-CA is Benign according to our data. Variant chr7-5997349-GG-CA is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 182818.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=4, Likely_benign=1, Benign=1}.
The c.779_780delCCinsTG variant (also known as p.S260L), located in coding exon 7 of the PMS2 gene, results from an in-frame deletion of CC and insertion of TG at nucleotide positions 779 to 780. This results in the substitution of the serine residue for a leucine residue at codon 260, an amino acid with dissimilar properties. This variant was identified in 1/177 individuals with pancreatic ductal adenocarcinoma undergoing multi-gene panel testing (Cremin C et al. Cancer Med, 2020 06;9:4004-4013). Based on data from gnomAD, the TG allele has an overall frequency of 0.018% (50/282054) total alleles studied. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive (Choi Y et al. PLoS ONE. 2012; 7(10):e46688). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
May 09, 2022
Color Diagnostics, LLC DBA Color Health
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing
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Lynch syndromeUncertain:1
Apr 03, 2024
Department of Pathology and Laboratory Medicine, Sinai Health System
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing
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not providedUncertain:1
Apr 21, 2025
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing
In silico analysis supports a deleterious effect on protein structure/function; Observed in an individual with pancreatic cancer (PMID: 32255556); This variant is associated with the following publications: (PMID: 32255556, 11574484) -