No association of Catechol-O-Methyltransferase (COMT) Gene Haplotypes in Patients with Schizophrenia in a Turkish Sample

Objective: The dopaminergic system, especially variations in the catechol-O-methyltransferase (COMT) gene, is of major interest in the etiology of schizophrenia. The rs4680 (Val108/158Met), rs165599, and P2 promoter rs2075507 single nucleotide polymorphisms (SNPs) in the COMT gene have been shown to be associated with alteration of COMT gene expression and COMT enzyme activity. The aim of this study was to investigate a possible association between schizophrenia and the haplotypes of these polymorphisms. Methods: The sample was comprised of 181 patients with schizophrenia and 368 healthy controls. The patients' psychotic symptoms were rated using the Positive and Negative Symptom Scale (PANSS). COMT rs2075507, rs4680, and rs165599 SNPs were evaluated by a polymerase chain reaction, followed by restriction fragment length polymorphism analysis. These SNPs in the COMT gene were subjected to haplotype analyses using Haploview ver. 4.2. Results: No significant differences were found between COMT rs2075507, rs4680, and rs165599 SNPs in schizophrenic patients and controls. The patients' PANSS results were not associated with these SNPs. No associations were obtained between 2 and 3-haplotypes of rs2075507, rs4680, rs165599 SNPs and schizophrenia. Conclusion: COMT rs2075507, rs4680, rs165599 SNPs and haplotypes do not appear to be risk factors for schizophrenia in this population.