Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an inherited condition that runs in the family and causes an increased risk for people who have it to grow many (over one hundred) polyps in their colon. Polyps are abnormal growths of tissue that can turn into cancer if left untreated. The type of polyps found in FAP are called adenomatous polyps. There is also a predisposition for developing other cancers including: small intestinal cancer, pancreatic cancer, thyroid cancer, and hepatoblastoma (tumor of the liver) in children. Having a mutation in the APC genes does not guarantee someone will develop cancer. However, if left untreated, up to 93% of individuals with FAP will develop colon cancer by age 50.

In addition to the standard form of FAP, there are two milder forms of this condition: attenuated familial adenomatous polyposis (AFAP) and MUTYH-associated polyposis (MAP). These forms of FAP are associated with less polyps, but still carry a higher risk of colon cancer than the average person.