Genetic Polymorphisms in the HTR2C and Peroxisome Proliferator-Activated Receptors Are Not Associated with Metabolic Syndrome in Patients with Schizophrenia Taking Clozapine

OBJECTIVE Genetic variation in the serotonin-2C receptor encoded by the HTR2C gene is one of the genetic determinants of antipsychotic-induced weight gain. Peroxisome proliferator-activated receptors are nuclear receptors regulating the expression of genes involved in lipid and glucose metabolism. In this cross-sectional study, we investigated whether HTR2C-759C/T, HTR2C-697G/C, PPARα V227A, and PPARγ 161C/T genotypes were associated with metabolic syndrome (MetS) in patients with schizophrenia taking clozapine. METHODS One hundred forty-six Korean patients using clozapine for more than one year were genotyped for the HTR2C-759C/T, HTR2C-697G/C, PPARα V227A, and PPARγ 161C/T polymorphisms, and their weight, waist circumference, blood pressure, triglycerides, high-density lipoprotein-cholesterol, total cholesterol, and glucose were measured. We used the criteria for MetS proposed by the National Cholesterol Education Program-adapted Adult Treatment Panel III. RESULTS The prevalence of MetS was 47.3% and was similar among men (49%) and women (42.9%). We found no significant differences between patients with and without MetS in terms of genotypes or allele frequencies. Logistic regression analyses also revealed no association between MetS and each genotype. CONCLUSION We did not find significant associations between four polymorphisms (HTR2C-759C/T, HTR2C-697G/C, PPARα V227A, and PPARγ 161C/T) and MetS in patients with schizophrenia taking clozapine.