Genetic studies on alcohol-metabolizing enzymes: detection of isozymes in human hair roots

Human liver alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) play an important role in alcohol metabolism. It has been shown that both enzymes are polymorphic and that different variants may be responsible for individual and racial differences in biological sensitivity to ethanol. However, for lack of a suitable peripheral enzyme source, no information is available regarding family data and the mode of inheritance of ADH and ALDH. Using sensitive micro-methods, we report here the detection of these enzymes and their variant forms in human hair root cells. The isozyme pattern of both enzymes obtained by isoelectric focusing from human liver, cultured fibroblast and hair root cell extracts are presented. Several German, Japanese and Vietnamese families were investigated. ALDH was found polymorphic only in Mongoloid populations. Phenotype distribution in a random Japanese population and families suggest a direct relationship between the absence of ALDH I isozyme and alcohol-induced biological sensitivity commonly observed in individuals of Mongoloid origin.