Familial Adenomatous Polyposis (FAP)

Familial Adenomatous Polyposis is an inherited condition, primarily affecting the colon and rectum. Although uncommon in the general population, FAP may be very common in affected families. People with FAP have a 50% chance of passing the condition to each of their children. People who inherit it develop numerous polyps on the inner lining of their colon and/or rectum. These polyps (also called adenomas) develop in the teenage years. If untreated, one or more of the polyps eventually will become cancerous in young adulthood. Fortunately, FAP can now be detected early and treated successfully. With prompt treatment, FAP patients lead normal, healthy lives.

Most patients develop polyps without symptoms. However, the following symptoms may occur: blood in the stool, diarrhea, constipation, crampy abdominal pain, decrease in size of stool, weight loss.

In addition to polyps, abnormalities in other areas of the body may give early clues to the presence of FAP. These signs include:

  • bumps or lumps on the bones of the legs, arms, skull, and jaw;
  • cysts of the skin;
  • teeth that do not erupt when they should; and,
  • freckle-like spots on the retina of the eye.

It should be emphasized that there is no safety in simply waiting for symptoms to develop.

The abnormal gene that causes FAP in most patients is now known. A blood test can be performed to find out whether or not a person who is the child of an individual with FAP has the abnormal gene and will eventually develop FAP. However, an abnormal gene can not be detected in some FAP families.

This test requires a small blood sample. The gene test result will influence the future management of individuals who are at risk for FAP. For example, if the test shows that a person does not have the abnormal gene, colon examinations can be spaced at longer intervals. If the test shows that a person does have the abnormal gene, then the physician will need to be alerted to schedule yearly colon examinations starting at the age of 11 years.

Flexible sigmoidoscopy is the primary test used to examine the inside of the lower part of the colon. It is done with a lighted, flexible, hollow tube, which is inserted into the anus. At sigmoidoscopy, the doctor can determine whether polyps or cancer are present. Most patients feel little or no discomfort during this examination.

If polyps are found during the examination, the doctor will recommend colon surgery. Removing the colon is the only way to prevent the development of colon cancer. Several different operations are used successfully. Your physician will discuss the best procedure for you.