Genotyping was completed for 135 SNPs in ten DA system genes, but 10 SNPs were excluded because of a low genotyping rate (<80%) and 24 because of a MAF < 0.01. The average genotyping call rate for the remaining 101 SNPs was 98.7% (90.6 to 100%). All remaining SNPs were in Hardy–Weinberg equilibrium (regular cutoff p-value of 0.001). Geno-typing error rate was estimated using duplicates at 0.6%. Among the 1054 genotyped individuals, 26 (8 cases and 18 controls) were excluded because of ≥20% missing genotypes, leaving a total of 1,028 individuals. Of them, 592 individuals were missing no genotypes, 374 were missing 1 to 5, 40 were missing 6 to 10, 15 were missing 11 to 15, and 7 were missing 16 to 20. After QC measures were completed, the following number of SNPs from each gene were entered in standard analysis: 4 SNPs in DRD1, 15 in DRD2, 13 in DRD3, 4 in DRD4, 7 in DRD5, 11 in SLC18A2, 12 in SLC6A3, 22 in DDC, 3 in TH, and 10 in COMT.
