About 3% of cases of gastric cancer (GC) cases are due to hereditary predisposition. Molecular causes of inherited predisposition to diffuse GC among Russian patients have not been studied. In the present work there was performed the molecular genetics study in 9 probands with signet-ring cell GC. Search of hereditary mutations was conducted in a suppressor gene of diffuse GC - the gene CDH1. We have discovered a new hereditary mutation (c.1005delA) and one rare variant (s.2253C> T). Frequency of hereditary mutations in sample of patients Russian was 1/9 (11,1%).