In summary, we mapped a) four risk loci for MaxAlc in EUR, of which only one (ADH1B) was previously known; b) one in AFR, which was previously known (a different marker in ADH1B than in EUR); and c) an additional two loci, both novel, in the transpopulation meta-analysis. MaxAlc is a clinically meaningful trait that differs from, but is genetically correlated with, DSM diagnosis of AUD. It is unclear to what extent the novel findings are due to the phenotype definition, or to the size and other characteristics of the clinical sample. MaxAlc, relating not merely to habitual alcohol use but to maximal habitual use, is more strongly related to the pathological range of alcohol use than some other measures such as the Alcohol Use Disorders Identification Test - Consumption (AUDIT-C) or MAXDRINKS (63). The negative correlation with “healthy” alcohol use behaviors, such as “alcohol usually taken with meals,” supports this interpretation.
