Lack of an allelic association between polymorphisms of the dopamine D2 receptor gene and alcohol dependence in the German population.
Our study examined recent claims of an association of the TaqI A1 allele and the functional -141C Ins allele of the dopamine D2 receptor (DRD2) gene with alcohol dependence. Genotypes of the TaqI A and -141C insertion/deletion polymorphisms were assessed in 196 German nonalcoholic controls and 310 German alcohol-dependent subjects, including two more homogeneous subgroups selected by either a history of parental alcoholism (n = 108) or by a history of severe physiological alcohol withdrawal symptoms (n = 99). We found no association between any of the biallelic variants or the A1/Ins haplotype and alcohol dependence (p > 0.05). Our present association results failed to replicate evidence that either the TaqI A1 allele or the functional Ins allele or the A1/Ins haplotype of the DRD2 gene confers vulnerability to alcohol dependence in the German population.