Dopamine D2 Receptor Gene Polymorphism in Cigarette Smoking

Lee, Hong Seock; Song, Sung Min; Lee, Heon Jeong

Abstract

OBJECTIVE
This study was to examine the effects of DRD2 TaqI A polymorphism on the smoking in Koreans. Also this study examined molecular heterosis and gender difference in the genetic effect of cigarette smoking.
METHODS
DRD2 TaqI A RFLP genotyping was carried out with DNA extracted from blood samples of 187 healthy individuals including 94 smokers and 93 non-smokers,
RESULTS
Among the total subjects, the smokers were not significantly different from the non-smokers in respect to the frequency and prevalence of A1 allele, the genotype distribution, or the frequency of heterozygotes. Separating the subjects by gender, however, in male subjects smokers showed a significantly higher frequency (p=0.049) and prevalence of A1 allele (p=0.016) than non-smokers. Also, genotype distribution (p=0.055) and frequency of heterozygotes (p=0.058) of smokers showed some different distributions, but there were no significant statistical difference. In contrast, female subjects showed significant difference between smokers and non-smokers in the comparison of frequency of heterozygotes (p=0.018), but not in the comparison of the frequency (p=0.582) and prevalence (p=0.082) of A1 allele and genotype distribution (p=0.060).
CONCLUSION
No significant difference between smokers and non-smokers in the genotype distributions of the total sample could be explained by the reciprocal effects of gender difference in the genetic effect of DRD2 A1 allele of the smoking. Our findings support gender difference and molecular heterosis at the DRD2 gene effects of smoking.