Many alcohol researchers believe that a person's genetic predisposition interacts with their environment to produce his or her overall risk for alcoholism. In addition, ethnic differences in rates of alcohol use and abuse have been linked to differences in the genes that code for certain enzymes that break down alcohol.
Two enzymes in particular - alcohol dehydrogenase (ADH) and mitochondrial aldehyde dehydrogenase (ALDH) - are highly involved in alcohol metabolism. The ADH2*3 allele (a variation of the gene) has been documented to occur only in persons of African descent and certain Native American tribes. A study in the December issue of Alcoholism: Clinical & Experimental Research investigates if an association exists between the presence of ADH2*3 alleles in young African American adults and a family history of alcohol dependence.
"We know that alcoholism is hereditary," said Cindy L. Ehlers, associate professor of neuropharmacology at The Scripps Research Institute and lead author of the study. "But we only have very limited information on what is inherited, and almost no information on what genes might be involved except in the case of alcohol metabolizing enzymes."
Differences in alcohol metabolizing enzymes, and the genes that encode them, are the best understood factors that influence drinking behavior and the risk of alcoholism. Alcohol is metabolized principally in the liver by two enzymes that act sequentially. ADH converts alcohol to acetaldehyde, aldehyde dehydrogenase (ALDH) subsequently converts acetaldehyde to acetate. Acetate i