NO ASSOCIATION BETWEEN POLYMORPHISMS IN THE HUMAN DOPAMINE D-3 AND D-4 RECEPTORS GENES AND ALCOHOLISM

The human dopamine D-2 receptor gene (DRD2) has received considerable attention for the past several years as a potential candidate that may affect susceptibility to alcoholism. The association studies that com pared the frequencies of alleles of DRD2 gene between alcoholics and c ontrol groups have produced equivocal results. Dopamine D-3 and D-4 re ceptor genes (DRD3 and DRD4) are in the same class as DRD2 but with di fferent pharmacological properties, We have used relative risk and hap lotype relative risk approaches to test associations between alleles o f DRD3 and DRD4 genes and alcoholism. For relative risk studies 162 pr obands from multiple incidence alcoholic families have been compared t o 89 psychiatrically normal controls. Haplotype relative risk approach es have used 29 alcoholic probands in which both parents were availabl e for genotyping. The Bal I restriction enzyme site in DRD3 and tandem repeat (VNTR) in DRD4 genes polymorphisms were used to genotype the a bove samples. The results of relative risk approaches for both DRD3 an d DRD4 genes were negative for comparisons of alcoholics and subtypes of alcoholics with normal. controls. Haplotype relative risk approache s also were negative for both genes. These results suggest that any ro le played by these receptors may account for only part of the variatio n in susceptibility to alcoholism. Am, J. Med. Genet. 74:281-285, 1997 . (C) 1997 Wiley-Liss, Inc.