PMS2 and hereditary nonpolyposis colon cancer: Lynch syndrome (formerly known as hereditary non‐polyposis colorectal cancer; HNPCC) is a hereditary condition caused by a germline pathogenic or likely pathogenic variant in one of four DNA mismatch repair (MMR) genes: MLH1, MSH2, MSH6, and PMS2. 1It can also be caused by a deletion in EPCAM, which leads to hypermethylation of the MSH2 promotor.2