In 1999, the International Gastric Cancer Linkage Consortium (IGCLC) defined families with the HDGC syndrome associated with CDH1 germline mutations as those fulfilling one of the following criteria1: (a) two or more documented cases of Diffuse Gastric Cancer (DGC) in first‐ or second‐degree relatives, with at least one diagnosed before the age of 50 years; (b) three or more cases of documented DGC in first‐ or second‐degree relatives, independent of the age of onset. The gene discussed is CDH1; the disease is Familial gastric cancer.