Familial Adenomatous Polyposis

Overview

Familial adenomatous polyposis (FAP) is a genetic disorder that left undetected, almost always leads to colon cancer by the time a person reaches his or her 40s. Screening and genetic testing, however, can help detect this condition early in life and greatly reduce the chances that cancer will develop.

FAP is rare (accounting for only about 1 percent of cases of colorectal cancer), but it is often treated in both adults and children at Mayo Clinic, one of the world's largest colon cancer treatment centers. Mayo Clinic in Minnesota is ranked No. 1 in Digestive Disorders by U.S. News & World Report.

Diagnosis

Because FAP often has no symptoms, especially early on, screening and genetic testing play key roles in detection. Read more about familial adenomatous polyposis diagnosis.

Treatment Options

Patients with FAP develop too many polyps to be removed one by one, so surgery to remove the entire colon and rectum is often necessary. Fortunately, this surgery can usually be done without the need for a colostomy (bag to collect waste). Mayo Clinic has great expertise in performing these colostomy-sparing surgeries. Read more about familial adenomatous polyposis treatment options.

• Treatment in Arizona
• Treatment in Florida
• Treatment in Minnesota
• Treatment of Children & Adolescents

About FAP

Genetic screening is recommended to try to prevent familial adenomatous polyposis.

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Familial adenomatous polyposis is a rare form of inherited colon cancer that causes hundreds to thousands of polyps to develop in the lining of the lower intestine (including the colon and rectum). Polyps usually form in the upper intestine as well (duodenal polyps) and sometimes desmoid tumors form in other parts of the body.

FAP results from a defect in the adenomatous polyposis coli (APC) gene and is autosomal dominant, meaning that only one parent must carry the mutated (abnormal) gene for a child to have a 50 percent chance of inheriting the disorder. However, in as many as one-third of people with FAP, the mutation occurs around the time of conception and neither parent carries the mutated gene.

Several Variations

FAP has several variations:

• Attenuated FAP. Growth of the polyps is delayed, usually until adulthood.
• Gardner Syndrome. Noncancerous tumors may develop in other parts of the body including the skin (sebaceous cysts and lipomas), bone (osteomas) and abdomen (desmoids).
• Turcot Syndrome. In addition to polyps in the intestinal tract, tumors may develop in the brain. (See gliomas.)