Hereditary polyposis syndromes (HPS) including familial adenomatous polyposis (FAP), juvenile polyposis syndrome (JPS), and Peutz-Jeghers syndrome (PJS) are all predisposing conditions to colorectal cancer, with a genetic basis (mutations in SMAD4 or BMPR1A genes). The gene discussed is SMAD4; the disease is juvenile polyposis syndrome.