Association study of catechol-O-methyltransferase gene polymorphism in Korean male alcoholics

Objective: Catechol-O-methyltransferase, which has a functional genetic polymorphism, plays an important role in dopamine metabolism. The study analyzed the association between the catechol-O-methyltransferase gene polymorphism and alcohol dependence in the Korean population. Methods: Ninety-seven male alcoholics and 94 male age-matched normal controls were enrolled in this study. Polymerase chain reaction-based genotyping was used to verify the presence of the catechol-O-methyltransferase gene polymorphism. The patients were divided into two subtypes (violent group and non-violent group) according to their history of violent behavior. Results: No difference in the distribution of the catechol-O-methyltransferase genotypes (H/H, H/L, L/L) and alleles (H, L) was observed between the patients and the controls. However, the differences between the violent and non-violent groups were significant in terms of the frequencies of the COMT genotypes (χ² = 7.977, df = 2, P = 0.019) and the alleles (χ² = 6.832, df = 1, P = 0.012). In addition, significant differences in the frequencies of the catechol-O-methyltransferase allele (χ² = 4.481, df=1, P=0.040) were observed between the non-violent group and the controls. Conclusions: This suggests that the catechol-O-methyltransferase gene polymorphism is not associated with the development of alcohol dependence, but may affect the susceptibility to a clinical heterogeneity of alcohol dependence, at least in the Korean population.