Approximately 3% of CRC are associated with Lynch syndrome, also referred to as hereditary non-polyposis colorectal cancer (HNPCC), an autosomal dominant disease and the most common inherited form of CRC arising from monoallelic germline mutation in MLH1, MSH2, MSH6, or PMS2 [2]. The gene discussed is PMS2; the disease is colorectal carcinoma.