Lynch syndrome (LS) is an autosomal dominant cancer predisposition syndrome caused by germline pathogenic variants (PVs) affecting one of four mismatch repair (MMR) genes: MLH1, MSH2, MSH6, and PMS2. These PVs include germline 3’ deletions in the EPCAM gene that lead to hypermethylation of surrounding DNA, including the downstream promoter of MSH2 causing MSH2 silencing. This evidence concerns the gene MSH2 and Leigh syndrome.