Abstract
Numerous polyposis syndromes involve the gastrointestinal (GI) tract, including both non‐hereditary and hereditary types. Causative genes are now known for the seven major syndromes. Genetic and clinicopathologic features are reviewed here and cancer predisposition is emphasized. Genetic testing is available for the GI polyposis syndromes, and can be accessed through GeneTests‐GeneClinics on the Internet at http://www.genetests.org/. The website is available at no cost and is a publicly funded medical genetics resource for health care providers and researchers.