OBJECTIVETo explore the relationship between genetic polymorphisms of the ethanol metabolizing enzymes and the occurrence of alcoholic liver disease (ALD).

METHODSSixty-five healthy male controls and 165 alcoholisms (including 122 ALD patients and 43 male alcohol abusers without liver complications defined as alcohol-dependent) were analyzed by polymerase chain reaction and hybridized with oligonucleotide microarray to detect the polymorphisms of the ethanol metabolizing enzymes genes.

RESULTSThe frequencies of alcohol dehydrogenase gene 2 * 1 ( ADH2 * 1 ) allele were shown as 37.69%, 46.51% and 59.02% in control, alcohol-dependent and ALD groups respectively; while those of ADH2 * 2 allele were shown as 62.31 %, 53.49% and 40.98% respectively. No ADH2 * 3 was detected in any of the subjects. The frequency of ADH2 * 1 was significantly higher in alcoholisms (ALD group and alcohol-dependent group) than in healthy controls ( P < 0. 01), and significantly higher in ALD group than in alcohol-dependent group ( P < 0.05) . The frequency of ADH3 * 2 was significantly higher in alcohol-dependents than in healthy controls ( P < 0.05) . The frequencies of ALDH2 * 2 allele mutation were significantly lower in alcoholisms than that in the healthy controls, and the deference between ALD group and alcohol-dependent group was significant. No homozygotes for the mutant ALDH2 * 2 allele were found in either alcoholic groups.

CONCLUSIONSPolymorphic ADH2, ADH3 and ALDH2 genes can affect the propensity for alcohol drinking in Chinese. The alleles of ADH2 * 2, ADH3 * 1 and ALDH2 * 2 are most likely to play a protective role against excessive consumption. ADH2 * 2 and ALDH2 X 2 may contribute to susceptibility for ALD.