Allelic association between D2 but not D1 dopamine receptor gene and alcoholism in Finland.

We studied the relationship of D2 and D1 receptor gene polymorphisms and alcoholism in male Finnish alcoholics and assessed male controls. Seventy alcoholics entering a detoxification programme and 50 control individuals were recruited. Forty-three per cent of the alcoholic patients, but only 22% of controls, had the D2 receptor gene TaqI A restriction fragment length polymorphism A1 allele. The frequency of the A1 allele was significantly higher in alcoholics (p = 0.039). In comparison, no association between alcoholism and the D1 receptor gene EcoRI restriction fragment length polymorphism alleles was found. A logistic regression analysis of the alcoholic population failed to support the idea that the presence of the A1 allele would be linked to estimates of alcohol dependence severity rated with the Severity of Alcohol Dependence Questionnaire or the Michigan Alcoholism Screening Test. In conclusion, allelic association between the D2 but not D1 receptor gene and alcoholism in a genetically relatively homogenous population of male Finns was found. The results are in agreement with the view that the D2 receptor locus is involved in genetic susceptibility to alcoholism but does not give support to a special association of severe alcohol dependence and the A1 allele of the D2 receptor gene.