Familial adenomatous polyposis (FAP) is characterized by the development of hundreds to thousands of adenomas in the rectum and colon during the second decade of life. The disease is MONDO_0021055 (classic familial adenomatous polyposis). Also known as: FAP, Familial Adenomatous Polyposis, adenomatous polyposis coli, adenomatous polyposis of the colon, classic FAP, colorectal adenomatous polyposis, familial adenomatous polyposis, familial adenomatous polyposis coli.