CDH1-related diffuse gastric and lobular breast cancer syndrome (MONDO_0100488) is germline pathogenic or likely pathogenic variants in the CDH1 gene predispose to hereditary diffuse gastric cancer, a cancer susceptibility syndrome inherited in an autosomal dominant pattern, initially characterized by the increased risk for diffuse gastric cancer (DGC) but subsequently well documented to be associated with lobular breast cancer (LBC) in women. Also known as: DGLBC, HDGC, LBC, diffuse gastric and lobular breast cancer syndrome, gastric cancer, familial diffuse breast cancer, lobular, gastric cancer, hereditary diffuse.