Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PVS1_ModeratePM2BP6
The NM_001322015.2(PMS2):c.-456-2A>G variant causes a splice acceptor, intron 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. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
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.
PVS1
Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.05877193 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.3, offset of -5, new splice context is: cttgtaactgatttctctAGtac. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
PM2
Very rare variant in population databases, with high coverage;
BP6
Variant 7-6006028-T-C is Benign according to our data. Variant chr7-6006028-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 2121743.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.
Uncertain significance, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Apr 05, 2022
This variant has not been reported in the literature in individuals affected with PMS2-related conditions. 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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This variant is not present in population databases (gnomAD no frequency). This sequence change affects codon 9 of the PMS2 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the PMS2 protein. -
Lynch syndrome Benign:1
Likely benign, criteria provided, single submitter
clinical testing
All of Us Research Program, National Institutes of Health