 Familial gastric cancer FGC concerns about 10 of all gastric cancers. It has an impressive impact on both emotional and physical wellbeing of first degree relatives of patients with early onset of gastric cancer. FGC can in 1-3 be attributed to one single hereditary syndrome, the hereditary diffuse gastric cancer HDGC. HDGC is associated with a CDH1 mutation in about 40 of the cases. In case there is no CDH1 mutation, referred to as familiar diffuse gastric cancer FDGC, it remains uncertain how to guide andor screen family members. The same applies for the rare familial intestinal type gastric cancer FIGC. 