Accounting for the number of Māori CDH1 mutation carriers identified between 1998 and 2008 (P. Guilford, personal communication) and using a lifetime penetrance estimate of 70%, we estimate that in the absence of familial HDGC screening, germline CDH1 mutations would account for 6% of all advanced Māori gastric cancers and 13% of all diffuse-type gastric cancers. This evidence concerns the gene DSG2 and gastric cancer.