FAP : Screening & Diagnosis
Familial Adenomatous Polyposis (FAP) - Screening & Diagnosis: It is important to diagnose FAP in the asymptomatic stage by screening the relatives of an affected patient. At-risk family members can be offered genetic testing for APC mutations starting at age 10 to 12 years. Testing for APC mutations is done by DNA sequencing on leukocytes separated from a whole blood sample. Several commercial laboratories offer the assay. Children who test positive are offered sigmoidoscopy. Colonoscopy is, however, the preferred diagnostic method since it can exclude carcinoma elsewhere in the colon. The presence of more than 100 adenomas establishes the diagnosis of FAP.