Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_ModeratePM2PP5_Very_Strong
The NM_000251.3(MSH2):c.793-2A>C variant causes a splice acceptor, 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 (★★★).
MSH2 (HGNC:7325): (mutS homolog 2) This locus is frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). When cloned, it was discovered to be a human homolog of the E. coli mismatch repair gene mutS, consistent with the characteristic alterations in microsatellite sequences (RER+ phenotype) found in HNPCC. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]
Verdict is Pathogenic. Variant got 12 ACMG points.
PVS1
Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.053475935 fraction of the gene. Cryptic splice site detected, with MaxEntScore 8.8, offset of 7, new splice context is: ttcttaattttcggttgcAGttt. 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;
PP5
Variant 2-47414267-A-C is Pathogenic according to our data. Variant chr2-47414267-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 91210.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47414267-A-C is described in Lovd as [Likely_pathogenic].
International Society for Gastrointestinal Hereditary Tumours (InSiGHT)
Significance: Likely pathogenic
Review Status: reviewed by expert panel
Collection Method: curation
Interrupts canonical donor splice site -
May 01, 2018
University of Washington Department of Laboratory Medicine, University of Washington
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
MSH2 NM_000251.2:c.793-2A>C has a 99.4% probability of pathogenicity based on combining prior probability from public data with a likelihood ratio of 1.56 to 1, generated from evidence of seeing this as a somatic mutation in a tumor without loss of heterozygosity at the MSH2 locus. See Shirts et al 2018, PMID 29887214. -