Further pathogenic mechanisms could be related to methylation. In the ADH gene cluster, DNA methylation, which is also modulated by genetic variation, appeared to at least partially underlie the association of genetic variation with AD [Zhang and others 2014a]. Finally, our recent study extended our understanding of the ADH1B association with symptoms related to alcohol use disorders considering DSM-IV and DSM-5 diagnostic systems [Hart and others 2016]. We observed that ADH1B rs1229984 was related to a range of alcohol-related social/interpersonal problems and the associations were mediated by the maximum number of drinks consumed in a 24-hour period (a measure of innate tolerance), suggesting that variation in ADH1B affects the adaptation to heavy drinking [Hart and others 2016].
