Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000535.7(PMS2):c.903+1G>A variant causes a splice donor, intron 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. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).
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 Pathogenic. Variant got 18 ACMG points.
PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 7-5995533-C-T is Pathogenic according to our data. Variant chr7-5995533-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 993233.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Quest Diagnostics Nichols Institute San Juan Capistrano
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The variant disrupts a canonical splice site, and is therefore predicted to result in the loss of a functional protein. Not found in the total gnomAD dataset, and the data is high quality. -
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Department of Pathology and Laboratory Medicine, Sinai Health System
Significance: Uncertain significance
Review Status: no assertion criteria provided
Collection Method: clinical testing
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Nov 03, 2022
GeneDx
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Observed in an individual with a personal history consistent with pathogenic variants in this gene in the published literature (Shuen et al., 2019); This variant is associated with the following publications: (PMID: 30608896) -
Lynch syndrome 4 Pathogenic:2
Sep 19, 2023
Myriad Genetics, Inc.
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This variant is considered likely pathogenic. This variant occurs within a consensus splice junction and is predicted to result in abnormal mRNA splicing of either an out-of-frame exon or an in-frame exon necessary for protein stability and/or normal function. -
Dec 29, 2020
Baylor Genetics
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Review Status: criteria provided, single submitter
Collection Method: clinical testing
In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 993233). This variant has not been reported in the literature in individuals affected with PMS2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 8 of the PMS2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in PMS2 are known to be pathogenic (PMID: 21376568, 24362816). -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The c.903+1G>A intronic variant results from a G to A substitution one nucleotide after coding exon 8 of the PMS2 gene. This nucleotide position is highly conserved in available vertebrate species. Using the BDGP and ESEfinder splice site prediction tools, this alteration is predicted to abolish the native splice donor site; however, direct evidence is unavailable. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as likely pathogenic. -