FAMILIAL ADENOMATOUS POLYPOSIS (FAP) AND ATTENUATED FAMILIAL ADENOMATOUS POLYPOSIS (AFAP)

The second-most common form of hereditary colorectal cancer is familial adenomatous polyposis (FAP). FAP occurs in one in 10,000 people and is detected by the growth of hundreds to thousands of polyps (adenomas) in the colon, often at an early age.

The risk of developing colorectal cancer is 100% if left untreated. Attenuated familial adenomatous polyposis (AFAP) is a milder form of FAP, but still carries a higher risk for colon cancer than the average population. The gene that is associated with both FAP and AFAP is APC (adenomatous polyposis coli).