What is Familial Adenomatous Polyposis Syndrome?

Familial adenomatous polyposis (FAP) is a genetic disorder. It occurs when polyps (clumps of cells) form on the inside of a person’s colon (large intestine). These polyps can number in the hundreds to thousands. Other polyposis syndromes are “variants” of FAP. They include Gardner and Turcot syndromes, as well as distinct disorders such as juvenile polyposis syndrome and Peutz-Jaegers syndrome.

Children with variant forms of FAP have polyps in the colon. They also have other symptoms that happen outside the colon. For example, someone with Gardner syndrome may have cysts and tumors in other parts of their body, such as under the skin or in the jaw.

If not treated, people with FAP will develop colon cancer in their lifetime. This often occurs before 40 years of age. People with variant forms of FAP also are at increased risk for cancer. Rarely, colon cancers or other cancers can occur during childhood or the teen years.

Infants and young children with FAP are also at risk for a rare tumor of their liver called hepatoblastoma. They should be screened often for this cancer until they are 5-years old.