Familial adenomatous polyposis (FAP) is a genetic disorder characterized by the development of numerous polyps in the lining of the colon and rectum. These polyps typically begin to appear in adolescence or early adulthood and have a high risk of becoming cancerous if not treated. FAP is caused by mutations in the APC gene, which is responsible for regulating cell growth. Individuals with FAP often require regular screening and may undergo preventive surgery, such as a colectomy, to remove the colon and reduce cancer risk. Family members of affected individuals may also be tested for the APC gene mutation to determine their risk of developing the condition.