American College of Gastroenterology
Advancing Gastroenterology, Improving Patient Care

Familial Adenomatous Polyposis (FAP)

FAP Overview

Familial adenomatous polyposis, also known as "FAP," is a rare disease. The hallmark of this condition is the abnormal growth in the intestine is called a polyp. Polyps have a high propensity of turning into cancer but are not cancer by themselves.

Most people with FAP have 100s of thousands of polyps at a young age, and they have a very high risk of colon cancer. Without treatment, most people will develop colon cancer by the mid-30s to early 40s. There are also milder forms of FAP that have fewer polyps, less than 100. They tend to develop colon cancer at a later age.

FAP is a condition where people can also develop brain cancer, pancreas, thyroid, small intestine, and stomach. People with lesser or milder forms of February.


This condition is caused by an abnormal gene called APC. FAP runs in families. However, other people can also get this without having any family member without this condition. People who have this condition start showing signs of it in their teens or early 20s.


It may not cause any symptoms.

However, when it does, symptoms can vary from bleeding in the bowel movements, fatigue, and tiredness from hidden blood loss in the stools leading to anemia or low blood counts. In addition, some patients can develop changes in bowel habits like runny diarrhea, watery bowel movements, and constipation(which is trouble having bowel movements). Abdominal pain weight loss can also occur. In addition, some patients can have the sensation of fullness called bloating.

Risk Factors

Having a family member with this condition leads to increased risks in their children.


Multiple tests can assist with managing this condition.

Genetic testing: This is a blood test to look for the abnormal gene that causes FAP. Before the test, a genetic counselor generally talks to you and explained the implications of this result and the testing. A genetic counselor is a person who can help you understand what having the gene could mean for you and your family.

Other testing can include colonoscopy, sigmoidoscopy, or upper endoscopy.


Surgical treatment is most relevant in the situation as they may have to remove your large intestine called "colectomy. " This is the primary treatment for this condition. Special procedures like colonoscopy or endoscopy can treat milder forms of this condition by removing the polyps.

Author(s) and Publication Date(s)

Rohit Singhania, MD, SM, FACG, UMMS - Baystate Regional Campus, Springfield, MA – Published August 2021.

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