[Effects of genetic polymorphisms of ethanol-metabolizing enzymes on alcohol drinking behaviors].

Background/aims: Genetic variations of ethanol-metabolizing enzymes can affect alcohol drinking behavior. The aims of this study were to investigate and compare the distributions of these genetic polymorphisms between a healthy control group and a heavy drinker group which included an alcoholic liver cirrhosis group.

Methods: Genotypes of ADH2, ALDH2, CYP2E1, and catalase were identified by polymerase chain reaction and restriction fragment length polymorphism. Genomic DNA was extracted from peripheral leukocytes in 42 healthy controls, 12 heavy drinkers, and 30 alcoholic liver cirrhosis patients.

Results: 1) The genotype frequencies of ALDH2 (1*1), ADH2 (1*1), CYP2E1 (c1c1), and catalase1 (TT) were 69%, 55%, 38%, and 12%, respectively in healthy Korean males. 2) There was a significant difference in the distribution of the genetic polymorphism of ALDH2 between the control group and heavy drinker group (12 heavy drinkers and 30 alcoholic liver cirrhosis patients). The genotype frequency of ALDH2 mutant, ALDH2 (1*2) and ALDH2 (2*2) in the heavy drinker group (12%) was significantly lower than that in the control group (30%). 3) We didn't find anyone with ALDH2 homozygote mutant (DD) in the heavy drinker group. 4) There was no significant difference in the distribution of genetic polymorphisms in ADH2, CYP2E1 and catalase1 between the two groups.

Conclusions: These results suggest that the absence of ALDH2 mutant genotype is strongly related to heavy drinking behavior. We can not prove, however, any evidence that the polymorphisms of other ethanol-metabolizing enzymes are associated with the determination of alcohol-drinking behavior.