Analysis of covariance (ANCOVA) with age, sex, duration of disease, chlorpromazine equivalent (CPZEQ) incorporated as covariates showed that limb-truncal, but not orofacial TD, is associated with CYP1A2 (-163C>, rs762551) polymorphism (F = 3.27, P = 0.039).
No significant differences in genotypes frequencies of the CYP2D6 C100T polymorphism were observed between patients with TD and without TD (Chi2=4.078, P>0.05), but patients with TD had a significant excess of the T allele compared with those without TD (Chi2=4.28, P<0.05).