Among the DRD4 polymorphisms, the -616 C/G and -521 C/T promoter SNPs showed potentially interesting associations with borderline and antisocial traits (Table 2). The -616 CC and -521 TT genotypes were overrepresented among those who had 2 or more borderline or antisocial symptoms. In the second round of analyses homozygotes for the minor allele were grouped together with heterozygotes. Using the CC vs CG + GG grouping system at the -616 C/G SNP, the difference in genotype distribution was nominally significant for borderline symptoms (p = 0.010), whereas at the -521 C/T SNP the CC + CT vs TT grouping showed nominally significant results for both borderline (p = 0.029) and antisocial (p = 0.011) symptoms. In the Caucasian subgroup similar finding emerged for the -616 C/G SNP when testing borderline symptoms (χ2 = 6.732, df = 1, p = 0.009). Whereas at the -521 C/T SNP the analyses showed only marginal effect (borderline: χ2 = 3.609, df = 1, p = 0.057, antisocial: χ2 = 3.493, df = 1, p = 0.062). Neither of the nominally significant associations (p
