Orphanet rare-disease nomenclature identifier Orphanet_733 (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. Also known as: APC - adenomatous polyposis coli, FAP, adenomatous polyposis coli, adenomatous polyposis of the colon, classic FAP, classic familial adenomatous polyposis, colorectal adenomatous polyposis, familial adenomatous polyposis.