Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_000535.7(PMS2):c.961G>A(p.Val321Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000357 in 1,598,098 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. 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. V321A) 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
Institute for Clinical Genetics, University Hospital TU Dresden, University Hospital TU Dresden
Nov 03, 2021
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Uncertain significance, criteria provided, single submitter
clinical testing
GeneDx
Nov 29, 2023
In silico analysis supports that this missense variant does not alter protein structure/function; Observed in individuals with endometrial or colorectal cancer, some with tumors demonstrating isolated loss of PMS2 and/or microsatellite instability (PMID: 20205264, 25871621, 31992580); This variant is associated with the following publications: (PMID: 20205264, 25871621, 31391288, 31992580, 11574484) -
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Jun 21, 2023
The p.V321I variant (also known as c.961G>A), located in coding exon 9 of the PMS2 gene, results from a G to A substitution at nucleotide position 961. The valine at codon 321 is replaced by isoleucine, an amino acid with highly similar properties. This alteration has been reported as a variant of unknown pathogenicity in one individual from a cohort of 145 unrelated patient samples submitted for PMS2 whole gene analysis. Additionally, authors note that this individual's tumor exhibited isolated loss of PMS2 expression by immunohistochemistry (IHC) (Vaughn CP et al. Hum. Mutat. 2010 May;31:588-93). The alteration was also detected in the germline of a 54-year-old male diagnosed with two ascending colorectal cancers; both tumors exhibited isolated loss of PMS2 by IHC and high microsatellite instability (MSI-H), but this individual did not meet Amsterdam II criteria (Dudley B et al. Am. J. Surg. Pathol., 2015 Aug;39:1114-20). Additionally, this alteration was identified in an individual diagnosed with uterine cancer at 63. This individual's tumor exhibited loss of PMS2 expression by IHC (Wang Q et al. J Med Genet, 2020 07;57:487-499). This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Likely benign, criteria provided, single submitter
clinical testing
Color Diagnostics, LLC DBA Color Health
Dec 09, 2015
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not specified Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Oct 03, 2022
Variant summary: PMS2 c.961G>A (p.Val321Ile) results in a conservative amino acid change located in the DNA mismatch repair protein family, N-terminal (IPR002099) of the encoded protein sequence. Four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4e-05 in 251270 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in PMS2 causing Hereditary Nonpolyposis Colorectal Cancer (4e-05 vs 7.1e-05), allowing no conclusion about variant significance. c.961G>A has been reported in the literature in affected individuals whose tumors exhibited isolated loss of PMS2 expression by immunohistochemistry without strong evidence for causality (Dudley_2015, Vaughn_2010). These reports do not provide unequivocal conclusions about association of the variant with Hereditary Nonpolyposis Colorectal Cancer. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified as VUS (n=4) and likely benign (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -
PMS2-related disorder Uncertain:1
Uncertain significance, no assertion criteria provided
clinical testing
PreventionGenetics, part of Exact Sciences
Jul 01, 2024
The PMS2 c.961G>A variant is predicted to result in the amino acid substitution p.Val321Ile. This variant has been reported in individuals suspected to have Lynch syndrome, most of whom had tumors with isolated loss of PMS2 immunohistochemical expression (Wang et al. 2020. PubMed ID: 31992580). This variant is reported in 0.020% of alleles in individuals of European (Finnish) descent in gnomAD. Another nucleotide change affecting this amino acid (p.Val321Ile) has been reported in an individual with colorectal cancer (Jiang et al. 2019. PubMed ID: 30521064). This variant has conflicting interpretations of uncertain significance and likely benign in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/141713/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Uncertain significance, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Jan 28, 2024
This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 321 of the PMS2 protein (p.Val321Ile). This variant is present in population databases (rs377043696, gnomAD 0.02%). This missense change has been observed in individual(s) with Lynch syndrome-associated cancer (PMID: 20205264, 25871621, 31992580). ClinVar contains an entry for this variant (Variation ID: 141713). 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 not expected to disrupt PMS2 protein function with a negative 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. -
Lynch syndrome 4 Uncertain:1
Uncertain significance, criteria provided, single submitter