SMAD3 and juvenile polyposis syndrome: Other syndromes associated with MVP involving the TGFβ pathway are the juvenile polyposis syndrome (SMAD4: Mothers against decapentaplegic homolog 4 or SMAD family member-4 and BMPR1A: Bone morphogenetic protein receptor, type 1A), and the aneurysm-osteoarthritis syndrome (Mutations in SMAD3: SMAD family member-3).