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Genetic and Rare Diseases Information Center (GARD)

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Familial adenomatous polyposis


Other Names for this Disease

  • Adenomatous polyposis coli
  • Adenomatous polyposis of the colon
  • Familial adenomatous polyposis of the colon
  • Familial intestinal polyposis
  • Familial multiple polyposis
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

The father of my children lost his life after a short battle with colon cancer. Several members of his family had various other types of cancer. I would like to help my children prevent the development of cancer. What are the symptoms of familial adenomatous polyposis (FAP)? What steps can we take to be better prepared for this disease? Who can help us with this endeavor?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What are the signs and symptoms of familial adenomatous polyposis?

The signs and symptoms of familial adenomatous polyposis (FAP) vary both within families and between families. Classic FAP is characterized primarily by hundreds to thousands of noncancerous (benign) polyps (growths) in the colon that begin to appear at an average age of 16 years. Unless the colon is removed, these polyps will become malignant (cancerous), leading to early-onset colorectal cancer at an average age of 39 years.[1][2]

Other features of FAP may include:[2]
  • Fundic gland or adenomatous polyps of the stomach
  • Adenomatous polyps of the small intestines
  • Osteomas (benign bone tumors)
  • Dental abnormalities
  • Congenital hypertrophy of the retinal pigment epithelium (a flat, pigmented spot within the outer layer of the retina)
  • Benign skin abnormalities
  • Adrenal masses
  • Desmoid tumors
  • Other types of cancer (small bowel, stomach, pancreas, thyroid, central nervous system, liver, bile ducts, and/or adrenal gland)
Last updated: 11/26/2014

What types of polyps are associated with familial adenomatous polyposis (FAP)?

Hundreds to thousands of adenomatous polyps of the colon are the most common feature of familial adenomatous polyposis (FAP). By age 35, 95% of individuals with FAP have this type of polyp. Adenomatous polyps (often referred to as adenomas) are benign (noncancerous) growths that develop in the lining of the gastrointestinal tract. These polyps are often biopsied during a screening colonoscopy and graded as mild, moderate, or severe. Polyps graded as severe are more likely to progress to cancer. Once 20 to 30 polyps or multiple "severe" polyps develop, a colectomy (removal of colon) may be recommended to prevent cancer.[2][1]

Affected people may also develop fundic gland or adenomatous polyps of the stomach; however, the risk of these polyps advancing to stomach cancer is less than 1%. Gastric (stomach) fundic-gland polyps are hamartomatous (made up of an abnormal mixture of cells and tissues normally found in the area of the body where the growth occurs) and occur in approximately half of people with FAP. Gastric adenomatous polyps occur in about 10% of people with FAP.[2]

Adenomatous polyps of the duodenum (small intestine) are observed in 50-90% of people with FAP and are commonly found in the second and third portions of the duodenum. The lifetime risk of small bowel cancer is 4-12% with the majority occurring in the duodenum. In rare cases, adenomatous polyposis are also found in the gallbladder, although these growths are typically discovered late (over age 40).[2]
Last updated: 11/27/2014

Is genetic testing available for familial adenomatous polyposis?

Genetic testing is available for the gene known to cause familial adenomatous polyposis (FAP). Prenatal testing and genetic testing for at-risk relatives are possible if the disease-causing mutation in the family is known. Because colon screening for those at risk for classic FAP begins as early as age ten years, genetic testing is generally offered to children by this age. Testing may be offered earlier if the child is showing signs or symptoms of FAP.[2]

The Genetic Testing Registry (GTR) is a centralized online resource for information about genetic tests. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
Last updated: 11/26/2014

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:

Last updated: 11/27/2014

References
Other Names for this Disease
  • Adenomatous polyposis coli
  • Adenomatous polyposis of the colon
  • Familial adenomatous polyposis of the colon
  • Familial intestinal polyposis
  • Familial multiple polyposis
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.