Objective: The authors examined the genetic polymorphisms of alcohol dehydrogenase 2 and 3 (ADH2 and ADH3) and aldehyde dehydrogenase (ALDH2) in patients diagnosed as having Cloninger's type I or type II alcoholism.
Method: Seventy-two alcoholic men and 38 nonalcoholic, healthy men were tested for the distribution of genotypes and alleles of ADH2, ADH3, and ALDH2. Forty-eight of the alcoholic men had type I alcoholism, and 24 had type II alcoholism.
Results: The frequencies of ADH2*1 and ADH3*2 alleles were significantly higher in men with type II alcoholism than in men with type I alcoholism and healthy men. The frequency of the ALDH2*1 allele was significantly higher in men with alcohol dependence than in healthy men.
Conclusions: The genetic characteristics of alcohol dehydrogenases in men with type I alcoholism were similar to those of healthy men, and the genetic characteristics of aldehyde dehydrogenase in men with type I alcoholism were similar to those of men with type II alcoholism. These findings suggest that the genetic characteristics of alcohol metabolism in type I alcoholism fall between nonalcoholism and type II alcoholism.