Comparison of DRD2 rs1800497 (TaqIA) polymorphism between schizophrenic patients and healthy controls: Lack of association in a Turkish sample.

Abstract Objective. The association of DRD2 rs1800497 (TaqIA) polymorphisms and schizophrenia has been studied in a number of populations, but the results are contradictory. We aimed to define Taq IA allelic differences between schizophrenic and healthy subjects. Methods. The schizophrenic group consisted of 99 schizophrenic inpatients, diagnosed and treated at Gazi University Hospital Psychiatry Service, the healthy group was composed of 109 subjects who did not suffer from any psychiatric or organic diseases. High molecular weight genomic DNAs were prepared from peripheral venous blood cells by using proteinase K digestion followed by salt extraction method. Target DNA amplification of DRD2 gene (Taq1A, 310-bp region) was performed by polymerase chain reaction (PCR) with the primers 5014 and 971. Results. Of the 208 subjects involved in the study, 98.6% had A1 allele (hetero- or homo-zygote) and 1.4% had A2 allele (homozygote). While all schizophrenia patients had A1 allele, 97.2%, of the healthy subjects (n=106) had A1 allele and there was no significant difference between the groups. Conclusion. This study was the first study related to DRD2 polymorphism conducted in a Turkish schizophrenic patient sample. A great percentage of our sample has A1 allele. Our study could not find a significant association between schizophrenia and DRD2 rs1800497 polymorphism.