Familial Adenomatous Polyposis

Familial adenomatous polyposis (FAP) is a rare, inherited condition that causes colorectal cancer. FAP results in the development of hundreds of polyps inside the large intestine.

  • Causes

    FAP is caused by a genetic defect. Polyps usually begin developing during during the teenage years, and 95% of people with FAP will have polyps by age 35. The average person with FAP will have colorectal cancer found by the age of 39 years.

  • Definition

    Familial adenomatous polyposis (FAP) is a rare, inherited condition that causes colorectal cancer. FAP results in the development of hundreds of polyps inside the large intestine.

    Colon Polyp
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  • Diagnosis

    Your doctor will ask about your symptoms and medical history. A physical exam will be done. To confirm a diagnosis, your doctor will do some tests. These may include:

    • DNA analysis to determine if you have the defective gene
    • Biopsy to see if polyps are cancerous
    • Eye exam to look for lesions in the retina

    An endoscopy is a thin, lighted, telescope-like tube with a camera that is used to look for polyps inside the intestines. Endoscopy for FAP may include:

    • An exam of the stomach and the upper part of the small intestine
    • An exam of the rectum and colon

  • Prevention

    There are no current guidelines to prevent FAP.

  • Risk Factors

    The primary risk factor for FAP is having family members with this condition. However, this condition can occur in people without a family history of the condition. This is because the genetic defect can caused by a new mutation in the affected person.

  • Symptoms


    In the early stages, there may be no symptoms. When symptoms do occur, they may include:

    • Rectal bleeding or blood in the stool
    • Diarrhea
    • Cramping pain in the stomach
    • Weight loss
    • Bloating
    • Fatigue

  • Treatment

    FAP is treated with surgery. Since FAP causes so many polyps, they cannot be removed individually. Therefore, the goal of surgery is to remove the portion of the intestine that contains the cancerous or precancerous polyps. The surgical procedure used depends on the length of intestine involved.