Familial adenomatous polyposis

Adenomatous Polyposis Coli; Adenomatous Polyposis of the Colon; Colon cancer, familial; FAP; Hereditary Polyposis Coli; Polyposis coli

... Familial adenomatous polyposis, often called FAP, is an inherited colorectal cancer syndrome. Cancer usually develops in the lower part of the digestive system, including the colon (large intestine) and rectum. People with the classic type of familial adenomatous polyposis begin to develop multiple benign polyps (growths) in the large intestine as early as their teenage years. Some people, however, have a variant of the disorder—called attenuated familial adenomatous polyposis—in which polyp growth is delayed, typically until adulthood. The average age of onset for the attenuated polyposis variant is about 55, compared to onset 10 to 15 years earlier among people with classic familial adenomatous polyposis (average age of onset is about 39).

In people with classic familial adenomatous polyposis, the number of polyps increases with age and can include hundreds to thousands of polyps. Unless the colon is removed, these polyps will become malignant (cancerous). Also, of particular significance are desmoid tumors. These fibrous tumors usually occur in the covering of the intestines and may be initiated by abdominal surgery. With classic familial adenomatous polyposis and its attenuated variant, other growths, both benign and malignant, are sometimes found in other places in the body, especially the duodenum (part of the small intestine), stomach, bones, and other tissues.

A milder type of familial adenomatous polyposis, called autosomal recessive familial adenomatous polyposis, has also been identified. People with the autosomal recessive type of this disorder have fewer polyps than those with the classic type, typically less than 100, rather than hundreds or thousands. The autosomal recessive type of this disorder is caused by mutations in a different gene than classic and attenuated types of familial adenomatous polyposis. ...

Familial adenomatous polyposis (FAP) is an inherited condition in which num ...