Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000251.3(MSH2):c.1386+1G>C variant causes a splice donor, intron change. 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 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 2-47445658-G-C is Pathogenic according to our data. Variant chr2-47445658-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 90642.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47445658-G-C is described in Lovd as [Likely_pathogenic].
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The c.1386+1G>C intronic variant results from a G to C substitution one nucleotide after coding exon 8 of the MSH2 gene. This alteration was identified in a Belgian family that met Amsterdam Criteria (Spaepen M et al. Fam Cancer, 2006;5:179-89). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. In addition to the clinical data presented in the literature, 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. -