Approximately 1-3% of gastric cancers arise as a result of inherited gastric cancer predisposition syndromes. These may be of the diffuse or intestinal type. Linkage analysis has recently implicated E-cadherin mutations in an estimated 25% of families with an autosomal dominant predisposition to diffuse type gastric cancers. This subset of gastric cancer has been termed hereditary diffuse gastric cancer (HDGC).