Linkage and association of DRD2 Gene TaqI polymorphism with schizophrenia in an Iranian population

ABSTRACT

D2 dopamine receptor gene has been reported to be one of the most relevant candidate genes in schizophrenia. In this study, we investigated the association between TaqIA and TaqIB dopamine D2 receptor polymorphisms and psychopathology of schizophrenia. The study subjects were 38 acutely exacerbated schizophrenic patients who were all Iranian descent. The control population consisted of 63 healthy individuals with almost the same age as patients and were also of Iranian decent. The TaqIA and TaqIB genotypes, the A1 and A2 alleles, and the B1 and B2 were determined by restriction fragment length polymorphism of the amplified DNA fragments by polymerase chain reaction. For each polymorphism [A or B] the patients were categorized according to their genotype into three groups; i.e. the patients with alleles A1/A1, A1/A2, A2/A2; B1/B1, B1/B2, and B2/B2. No significant association was found between Taq1A or Taq1B gene polymorphisms and schizophrenia in patients compared to the controls. When study subjects were stratified according to their gender, the distribution of the A1/A1 genotype did was significantly different in both men and women [patients vs. controls]. Our findings show that there is no genetic association between Taq1A and Taq1B gene polymorphisms and schizophrenia. Further clinical studies should be conducted to confirm and further evaluate these findings: