Definition: A group of autosomal-dominant inherited diseases in which COLON CANCER arises in discrete adenomas. Unlike FAMILIAL POLYPOSIS COLI with hundreds of polyps, hereditary nonpolyposis colorectal neoplasms occur much later, in the fourth and fifth decades. HNPCC has been associated with germline mutations in mismatch repair (MMR) genes. It has been subdivided into Lynch syndrome I or site-specific colonic cancer, and LYNCH SYNDROME II which includes extracolonic cancer.
Other names Lynch Syndrome; Hereditary Nonpolyposis Colorectal Neoplasms; Hereditary Nonpolyposis Colorectal Cancer; Syndrome, Lynch; Lynch Syndrome I; Lynch Cancer Family Syndrome I; Hereditary Nonpolyposis Colon Cancer; Colorectal Cancer Hereditary Nonpolyposis; Colon Cancer, Familial Nonpolyposis