Dopamine receptor D2 (DRD2) TaqIA gene polymorphism and acute risperidone-induced changes in body weight, plasma glucose and lipid profile

There are indications that the transient blockade of the dopamine receptor D2 (DRD2) by atypical antipsychotics such as risperidone is related to their metabolic side effects. We, therefore, examined the relationship between TaqIA polymorphism of the DRD2 gene and acute risperidone-induced metabolic changes. We recruited 153 newly diagnosed patients with psychotic disorders (71 males and 82 females) from the Federal Neuropsychiatric Hospital, Yaba, Lagos, Nigeria. Body weight, fasting blood glucose (FBG), triglycerides (TG), total cholesterol (TChol), low-density lipoprotein cholesterol (LDLChol), and high-density lipoprotein cholesterol (LDLChol) were all determined at baseline and the end of 6 weeks of administration of risperidone (2 mg twice daily). DNA was also extracted from peripheral blood, and genotyping was carried out using the polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP). The relationship between the mean changes in the metabolic indices and the DRD2 TaqIA genotype was statistically determined. The frequencies of the A1A1, A1A2, and A2A2 were 0.229, 0.412, and 0.360, respectively. However, the population was not in HardyWeinberg equilibrium (chi(2) = 4.023, p < 0.01). The mean weight change and the mean changes in FBG, TG, TChol, and LDLChol were significantly (p < 0.05) higher among participants with the A1A1 genotype, followed by the heterozygous (A1A2) participants and lowest among those homozygous for the A2 allele. However, there was no significant difference in the mean change in HDLChol across all genotype groups. The DRD2 TaqIA1 allele is associated with higher risperidone-induced weight gain and metabolic changes among Nigerians.