Familial Adenomatous Polyposis (FAP) is a rare syndrome that increases the risk of colorectal cancer. FAP is characterized by the appearance of hundreds to thousands of polyps in the large intestine and rectum, which can develop into cancer if left untreated. At a relatively young age, a person with FAP is almost certain to develop colorectal cancer.

FAP is an inherited disease passed down in an autosomal dominant manner. It is caused by a mutation in the adenomatous polyposis coli (APC) gene, resulting in the formation of numerous polyps. This condition is also found in Gardner’s syndrome and Turcot’s syndrome, which are subtypes of FAP.

Symptoms and Diagnosis of FAP
The main sign of FAP is the appearance of hundreds or even thousands of polyps growing in the large intestine and rectum. Polyps typically start to appear in the mid-teens. These polyps have nearly a 100% chance of developing into colon or rectal cancer by the age of 40.

Other abnormalities in the body may indicate the presence of FAP, including:
– Lumps or masses on the bones of the legs, arms, skull, and jaw
– Cysts on the skin
– Teeth that do not emerge from the gums at the expected time
– Spots like freckles on the lining of the eyes

Diagnosis is usually done through a colonoscopy and genetic testing to detect mutations in the APC gene.

Risk Factors for FAP
The risk of developing familial adenomatous polyposis is higher if you have a parent, child, brother, or sister with this condition.

Complications of FAP
The polyps that appear in people with FAP are precancerous, and if left untreated, the risk of developing colon cancer is nearly 100%. Besides colon cancer, familial adenomatous polyposis can cause other complications, such as:
– Duodenal polyps. These polyps grow in the upper part of the small intestine and can become cancerous. However, with careful monitoring, duodenal polyps can often be detected and removed before they become cancerous.
– Periampullary polyps. These polyps appear where the bile and pancreatic ducts enter the duodenum (ampulla). Periampullary polyps may become cancerous, but they can often be detected and removed before they develop into cancer.
– Fundic gland polyps. These polyps grow in the lining of the stomach.
– Desmoids. These noncancerous masses can appear anywhere in the body but often develop in the abdomen. Desmoids can cause serious problems if they grow into nerves or blood vessels or compress other organs in your body.
– Other cancers. In rare cases, FAP can cause cancer to develop in the thyroid, central nervous system, adrenal glands, liver, or other organs.
– Benign skin tumors.
– Benign bone growths (osteomas).
– Congenital hypertrophy of the retinal pigment epithelium (CHRPE). This is a benign pigment change in the retina of the eye.
– Dental abnormalities. These include extra teeth or teeth that do not emerge.

Treatment of FAP
Treatment for FAP varies depending on the presence and severity of colonic and extracolonic manifestations of the disease. Factors such as age, overall health, and personal preferences can also influence FAP treatment.

Understanding and managing FAP is key to preventing the development of colorectal cancer and other complications. With careful monitoring and appropriate medical intervention, individuals with FAP can lead healthier lives and avoid the high risk of cancer. If you or a family member has a history of FAP, consult a doctor for proper management.

*This information has been reviewed by Rabbinu Rangga, MD (Gastroenterology Consultant)

Source:
Menon G, Carr S, Kasi A. Familial Adenomatous Polyposis. [Updated 2024 May 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538233/

Kanth, Priyanka, Yan Parc, Gabriela Moslein. Familial Adenomatous Polyposis Syndrome (Summary). [Updated 2023 Sept 14]. In: BMJ Best Practice US. Available from: https://bestpractice.bmj.com/topics/en-us/652

Half, E., Bercovich, D. & Rozen, P. Familial adenomatous polyposis. Orphanet J Rare Dis 4, 22 (2009). https://doi.org/10.1186/1750-1172-4-22

Johns Hopkins Medicine. Familial Adenomatous Polyposis. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/familial-adenomatous-polyposis

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