Germline mutations of the APC gene, which encodes a multidomain protein of 2843 amino acid residues, cause familial adenomatous polyposis (FAP). Truncating mutations in APC extreme 3’-end are rare and have not been clearly associated with a specific phenotype. Here we studied 101 clinically characterized patients harboring truncating mutations in APC extreme 3’-end in order to better decipher the patients’ phenotype. We report that mutations affecting APC distal portion identify a novel FAP clinical variant – Gastric Polyposis and Desmoid FAP (GD-FAP) – whose phenotype is characterized by colon oligopolyposis, diffuse gastric polyposis, and desmoid tumors. GD-FAP patients should start a tailored surveillance at the age of 20 by performing colonoscopy every 2-3 years, esophago-gastroduodenoscopy and abdominal ultrasound annually. (By Prof. Cristiano Simone, https://jmg.bmj.com/content/early/2019/10/04/jmedgenet-2019-106299 )