Mutations in the APC gene cause both common and attenuated familial adenomatous polyposis. These mutations affect the ability of the cell to maintain normal growth and function. Cell overgrowth resulting from mutations in the APC gene leads to the colon polyps seen in familial adenomatous polyposis.
Treatment for FAP depends on the genotype. Most individuals with the APC change will develop colon cancer by the age of 40. Therefore, prophylactic surgery is generally recommended before the age of 25. There are several surgical options that involve the removal of either the colon or both the colon and rectum. The choice to remove the rectum depends on the number of polyps in the rectum as well as the family history. If the rectum has few polyps, the colon is detached and the small bowel (ileum) is connected to the rectum (ileorectal anastomosis).
Familial adenomatous polyposis (FAP) is an inherited condition in which many polyps form mainly in the epithelium of the large intestine. While these polyps start out benign, malignant transformation into colon cancer occurs when not treated.