Association of D2 dopamine receptor and alcohol dehydrogenase 2 genes with Polynesian alcoholics

Alleles of the D2 dopamine receptor (DRD2) and the alcohol dehydrogenase 2 (ADH2) genes were determined in 69 French Polynesian alcoholic patients and 57 controls matched for racial origin. Three racial groups were studied: pure Polynesians (PP), Polynesians mixed with Callcasian (PGA) ancestry and Polynesians mixed with Chinese (PCH) ancestry. DRD2 Al allele frequencies in the alcoholics compared to their controls in these groups were: PP, .26 vs .32 (P = .69); PGA, .44 vs .35 (P = .46); PCH, .40 vs 0.39 (P = .88). ADH2 1 allele frequencies in alcoholics compared to their controls groups were: PP, .56 vs .62 (P = .66); PCA, .75 vs .56 IP = .09); PCH, .78 vs .32 IP = .009). In the PCA group, the combination of the DRDP Al genotypes and the ADH2 1 homozygotes was strongly associated with alcoholism (P = .0027). This preliminary study shows the importance of ascertaining racial ancestry in molecular genetic association studies. Moreover, it suggests that a combination of genes are involved in susceptibility to the development of alcoholism. (C) 2000 Editions scientifiques et medicales Elsevier SAS.