Our verdict is Uncertain significance. Variant got 0 ACMG points: 0P and 0B.
The ENST00000265849.12(PMS2):āc.2068A>Cā(p.Lys690Gln) variant causes a missense change. The variant allele was found at a frequency of 0.000027 in 1,592,150 control chromosomes in the GnomAD database, including 1 homozygotes. 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. K690R) 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]
Uncertain significance, criteria provided, single submitter
clinical testing
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Mar 14, 2023
Variant summary: PMS2 c.2068A>C (p.Lys690Gln) results in a conservative amino acid change located in the C-terminal dimerisation domain (IPR014790) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4.4e-05 in 247978 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in PMS2 causing Hereditary Nonpolyposis Colorectal Cancer (4.4e-05 vs 7.1e-05), allowing no conclusion about variant significance. In addition, the variant is located in a region that is highly homologous to PMS2 pseudogenes and the technology utilized for these datasets does not rule out pseudogene interference, therefore these data might not be reliable. The variant, c.2068A>C, has been reported in the literature in individuals affected with breast cancer and in another individual with endometrial carcinoma (Tung_2015, Ring_2016, Sahin_2022, Abdel-Razeq_2022), however it was also found in two individuals in a non-cancer related cohort (Kraemer_2019). These reports do not provide unequivocal conclusions about association of the variant with Hereditary Nonpolyposis Colorectal Cancer. At least one co-occurrence with another pathogenic variants has been reported (BRCA2 c.8904delC, p.V2969fs*7, our internal data), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Seven ClinVar submitters (evaluation after 2014) cite this variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Uncertain significance, criteria provided, single submitter
clinical testing
Genetic Services Laboratory, University of Chicago
Jan 20, 2022
This sequence has been previously described in individuals with breast cancer (PMID: 25186627) and endometrial cancer (PMID: 27443514). This sequence change has been described in the gnomAD database with a frequency of 0.0044% (dbSNP rs587781909); however, the frequency data for this variant in the population databases is considered unreliable due to its location in a region that is highly homologous to PMS2 pseudogenes. The p.Lys690Gln change affects a moderately conserved amino acid residue located in a domain of the PMS2 protein that is not known to be functional. In-silico pathogenicity prediction tools (SIFT, Align GVGD, REVEL) provide contradictory results for the p.Lys690Gln substitution. Due to insufficient evidence and the lack of functional studies, the clinical significance of the p.Lys690Gln change remains unknown at this time. -
Uncertain significance, criteria provided, single submitter
clinical testing
Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital
Uncertain significance, criteria provided, single submitter
curation
Sema4, Sema4
Sep 29, 2021
- -
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Jan 30, 2023
The p.K690Q variant (also known as c.2068A>C), located in coding exon 12 of the PMS2 gene, results from an A to C substitution at nucleotide position 2068. The lysine at codon 690 is replaced by glutamine, an amino acid with similar properties. This alteration has been reported in a cohort of 381 endometrial carcinoma patients who had undergone tumor testing to screen for Lynch syndrome (Ring KL et al. Mod. Pathol., 2016 Nov;29:1381-1389). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be inconclusive by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter
clinical testing
Color Diagnostics, LLC DBA Color Health
Jan 10, 2023
This missense variant replaces lysine with glutamine at codon 690 of the PMS2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 11/247978 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
not provided Uncertain:2
Uncertain significance, criteria provided, single submitter
clinical testing
Quest Diagnostics Nichols Institute San Juan Capistrano
Jun 25, 2020
- -
Uncertain significance, criteria provided, single submitter
clinical testing
GeneDx
Sep 11, 2024
Observed in individuals with endometrial, colorectal, or breast cancer (PMID: 25186627, 27443514, 33120919, 35402282, 37534630); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 27443514, 25186627, 31422574, 35402282, 2744351, 33120919, 35089076, 37534630) -
Breast and/or ovarian cancer Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario
May 21, 2020
- -
Lynch syndrome 4 Uncertain:1
Uncertain significance, criteria provided, single submitter