ALDH2 and alcohol dependence: The alcohol-metabolizing enzymes, such as the ADH genes (including ADH1A, ADH1B, ADH4, ADH5 and ADH6) and the aldehyde dehydrogenase (ALDH2) gene, had an effective impact on the alcohol metabolism pathway and the consequent alcoholism protective effect, which strongly indicated diverse ethnic-specific alcohol consumption patterns38–42.