The Dopamine D2 Receptor Gene and Alcoholism-Reply

In Reply.— Blum et al 1 evaluated a D 2 receptor polymorphism in 35 alcoholics and 35 nonalcoholics. Their subjects were dead and therefore were not psychiatrically interviewed. We 2 compared 40 interviewed alcoholics with 127 non-diagnosed population controls and reanalyzed two families by genetic linkage. We also tested a second marker at the D 2 locus. Both letters address only our population study and the Taq I restriction fragment length polymorphism data. Blum et al did not provide data for age of onset, severity, presence or absence of antisocial personality, or family history of alcoholism. These factors correlate with increased genetic risk for alcoholism. In our alcoholics, none of these variables was associated with either D 2 polymorphism. Also, both families with early-onset alcoholism provided evidence against linkage. As Noble and Blum state, it may be of interest that the Al allele was present in more of our severe