D2 Dopamine Receptor Gene Is Associated but Not Linked With Alcoholism

There has been intense interest in replicating the 1990 report inJAMAthat the minor allele ofDRD2(the D2dopamine receptor gene on human chromosome 11 at q22-q23) may increase susceptibility to severe alcoholism in some cases. In May 1990 Blum et al1reported that 24 (69%) of 35 alcoholics carried the Al allele ofDRD2compared with only seven (20%) of 35 nonalcoholics. Their analysis was based on brain tissue of deceased subjects, and the alcoholics were described as having experienced repeated treatment failures in their alcoholism rehabilitation, with their deaths attributable primarily to the chronic damaging effects of alcohol. It was surprising that a single gene could be so strongly associated with a common disorder that is known to be developmentally complex and genetically heterogeneous.2Accordingly, there was caution and skepticism about the report because of its small sample size and the surprising strength