Possible epistatic role of ADH7 in the protection against alcoholism.

In recent studies of the role of the alcohol dehydrogenase genes (ADH) in alcoholism the ADH1B Arg47His polymorphism appears to affect risk via a protective effect associated with the ADH1B*47His. Here we present evidence for an additional effect from outside the Class I ADH genes, presumably from functional variation at the ADH7 gene. The protective effect is restricted to one of two haplotypes identical at ADH1B but differing at an intronic SNP at ADH7 suggesting epistasis or strong linkage disequilibrium (LD). © 2003 Wiley-Liss, Inc.