Other than the set of alcohol metabolizing enzymes, the genetic locus probably most studied with respect to AD dopamine receptor (especially in the early 1990s) is the D2 locus, DRD2. Whether variation in this particular gene contributes to risk for alcoholism remains controversial. Reports of positive findings with what has been known historically as the DRD2 TaqI “A” system could be explained in terms of a small effect of polymorphic variation at this locus on risk, but it could also be explained in other ways, e.g., by population stratification or publication bias.
