A confirmed diagnosis of juvenile polyposis is thus based not only on the histopathological features of the polyps, but also on the patient’s physical findings and family history, and on the presence of germline mutations in SMAD4 and BMPR1A. The current patient had no family history of juvenile polyposis or germline mutations in the SMAD4 and BMPR1A genes but was diagnosed with juvenile polyposis of the stomach based on physical findings and histopathological features. Here, SMAD4 is linked to juvenile polyposis syndrome.