The A1 allele of the D2 dopamine receptor gene is associated with high dopamine transporter density in detoxified alcoholics.

The A1 allele of TaqI A restriction fragment length polymorphism (RFLP) in the D2 receptor (DRD2) gene locus has been suggested to be associated with low D2 receptor density in man. Striatal dopamine transporter (DAT) densities were studied with [(123)I]2-beta-carbometoxy-3beta(4-iodophenyl)tropane and single-photon emission tomography in 29 detoxified alcoholics, who were also genotyped for the two alleles of TaqI A RFLP at the DRD2 receptor gene locus. Alcoholics with the A1/A2 genotypes (n = 10) had statistically significantly higher DAT densities than subjects with the A2/A2 genotypes [n = 19; 8.0 +/- 1.2 (mean +/- SD) vs 6.9 +/- 1.1, P = 0.035]. We suggest that the TaqI A RFLP is in linkage disequilibrium with a gene variant modifying DAT density in alcoholics.