Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong
The NM_000535.7(PMS2):c.2446-2A>G variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. 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 16 ACMG points.
PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease,
PP5
Variant 7-5973544-T-C is Pathogenic according to our data. Variant chr7-5973544-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 265661.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This variant is denoted PMS2 c.2446-2A>G or IVS14-2A>G and consists of an A>G nucleotide substitution at the -2 position of intron 14 of the PMS2 gene. This variant destroys the canonical splice acceptor site and is predicted to cause skipping of terminal exon 15, including the stop codon. Such a deletion is predicted to result in an unstable transcript and subsequent degradation of the mRNA (Klauer 2012), or in an abnormal protein product. This variant has not, to our knowledge, been published in the literature. However, based on the currently available information, we consider PMS2 c.2446-2A>G to be a likely pathogenic variant. -
Jun 13, 2017
Quest Diagnostics Nichols Institute San Juan Capistrano
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The c.2446-2A>G intronic variant results from an A to G substitution two nucleotides upstream from coding exon 15 of the PMS2 gene. This nucleotide position is highly conserved in available vertebrate species. Based on two different splice site prediction tools, this alteration is expected to abolish the native splice acceptor site; however experimental evidence is not currently available. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein. As such, this alteration is classified as likely pathogenic. -