This study reports the results of genetic testing to identify germline variants in the main genes (APC, BMPR1A, MUTYH, PTEN, SMAD4, STK11) associated with hereditary polyposis syndromes in 75 index cases with colorectal polyps and a personal/family history of cancer that had been referred to genetic counseling at the Medical Genetics Unit of the National Institute of Gastroenterology “Saverio de Bellis”, Castellana Grotte, Bari, Italy. The gene discussed is SMAD4; the disease is cancer.