Background: The functional polymorphism (A118G) of the μ-opioid receptor gene (OPRM1) is thought to have clinical significance in the treatment of alcohol dependence. This study compared Koreans with one or two copies of the A118G polymorphism seeking treatment for alcohol dependence with a group of non–alcohol-dependent controls.
Methods: Patients hospitalized for alcohol dependence (n= 112) and a group of non–alcohol-dependent controls (n= 140) were interviewed on aspects of drinking history and psychiatric history. Patients and controls were excluded if they met criteria for any other major psychiatric disorder. Participants were genotyped at the OPRM1 locus.
Results: The allele frequency of the Asp40 allele was 0.397 in the alcohol-dependent group, which is consistent with other literature demonstrating this polymorphism to be common in Asian populations. Within the alcohol-dependent subjects, being homozygous for the Asp40 allele was associated with more days drinking than those heterozygous or homozygous for the Asn40 allele. Differences in the allele frequencies between alcohol-dependent and non–alcohol-dependent controls were not significant.
Conclusions: These results suggest that having one or two copies of the A118G allele is common among Koreans and may be an important genetic factor in the etiology of alcohol dependence and the frequency of alcohol consumption.