Family-based association analyses of alcohol dependence phenotypes across DRD2 and neighboring gene ANKK1.
Dopamine D2 receptors have been implicated in the biology of alcohol preference. We examined the -141 C Ins/Del polymorphism in the promoter region of the dopamine D2 receptor gene (DRD2) and the DRD2 TaqI A polymorphisms in 209 Japanese alcoholics and 152 age- and sex-matched Japanese controls. The Ins allele was significantly increased in the alcoholics, compared with the controls (p < 0.002, odds ratio = 1.82). The TaqI A1 allele tended to be more frequent in the alcoholics than in the controls (p < 0.04). Linkage disequilibrium between these two polymorphisms was weak (a maximum delta value = 0.13). The -141 C Ins/Del polymorphism may affect the vulnerability for alcoholism presumably through different expression of DRD2 in the Japanese.