This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Familial adenomatous polyposis (FAP) leads to the growth of hundreds to thousands of non-cancerous (benign) polyps in the colon and rectum. Overtime, the polyps can become cancerous (malignant), leading to colorectal cancer at an average age of 39 years. Symptoms of FAP may include dental abnormalities, tumors of the connective tissue (desmoid tumors), and benign and malignant tumors of the duodenum (a section of the small intestine), liver, bones, skin, and other tissues. Attenuated familial adenomatous polyposis (AFAP) is a milder form of FAP which includes fewer colon polyps (an average of 30). People with AFAP have an increased risk of developing colon cancer at a later age than classic FAP. FAP is due to genetic variants in the APC gene and is inherited in an autosomal dominant pattern. FAP is diagnosed based on the symptoms, clinical examination, and may be confirmed by the results of genetic testing. Management for FAP includes regular colon screening with endoscopy and other methods. Total removal of the colon (colectomy) is usually recommended to substantially reduce the risk for colon cancer. The recommended timing of surgery is based on multiple factors.
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