Patients with chronic addiction exhibit reduced dopamine D2 receptor (DRD2) availability in the striatum, and the <i>DRD2</i> TaqIA (rs1800497) and C957T (rs6277) genetic polymorphisms have previously been linked to individual differences in striatal dopamine metabolism and clinical risk for alcohol and nicotine dependence.
We found a significant genotype effect (all P≤0.017) for the following smoking-related phenotypes: (i) cigarettes smoked per day and CYP2A13*3; (ii) pack years smoked and CYP2A6*2, CYP2A6*1×2, CYP2A13*7, CYP2B6*4 and DRD2-ANKK1 2137G>A (Taq1A); (iii) nicotine dependence (assessed with the Fagestrom test) and CYP2A6*9.
Several SNPs (rs7131056, rs4274224, rs4648318, and rs6278) in DRD2, along with the Taq IA polymorphism (rs1800497) in ANKK1, revealed initial significant associations with ND in European Americans, but not after correction for multiple testing, indicating a weak association of DRD2 with ND.