The ALDH2 gene encodes mitochondrial aldehyde dehydrogenase 2 (ALDH2), a major acetaldehyde-metabolizing enzyme. Approximately 36% of East Asians (around 560 million people) carry an inactivating E504K missense mutation of the ALDH2 gene, which reduces ALDH2 enzymatic activity. This inactivating mutation has been correlated with several diseases and is strongly associated with type 2 diabetes, body mass index and serum lipids in East Asians.