Comparison of genetic polymorphisms of CYP2E1, ADH2, and ALDH2 genes involved in alcohol metabolism in Koreans and four other ethnic groups

Abstract

Background and objectives: Recent studies of the genetics of alcoholism have considered genetic factors in alcohol metabolism and have identified functional polymorphisms in genes encoding enzymes involved in ethanol metabolism. The aim of this study was to estimate the genotype and allele frequencies of polymorphisms of three major ethanol-metabolizing enzymes (ADH2, ALDH2 and CYP2E1) in Koreans and to compare them with those of other ethnic groups.

Methods: We chose three polymorphisms, ADH2 (*2), ALDH2 (*2) and CYP2E1 (c2), which are most likely to affect alcohol metabolism. To evaluate the allele frequencies of these single-nucleotide polymorphisms, 342 healthy Korean volunteers were recruited. Each genotype was determined by the TaqMan or SNaPshot method with genomic DNA extracted from peripheral leucocytes. We compared these allele frequencies with those of other ethnic groups registered on the International HapMap database.

Results and discussion: The allele frequencies in Koreans were 80.3% for the ADH2 (*2), 13.9% for ALDH2 (*2), and 20.9% for CYP2E1 (c2). Other Asians, including Japanese and Chinese populations, show similar frequencies (Japanese, 73.9%, 22.7%, and 20.5% respectively and Chinese, 76.7%, 15.6%, and 28.9% respectively), whereas African and European groups have quite different frequencies (Europeans, 0%, 0%, and 5.1% respectively and African, 0%, 0%, and 0% respectively).

Conclusion: Our current observations provide data on the prevalence of polymorphisms of ethanol-metabolizing enzymes, which should be useful in assessing the comparative susceptibility of different populations to diseases related to ethanol consumption.f ethanol-metabolizing enzymes, which should be useful in assessing the comparative susceptibility of different populations to diseases related to ethanol consumption.