Combined effect of polymorphic sites in the DTNBP1 and GRIN1 genes on schizophrenia

Background: Schizophrenia is a severe mental disorder and numerous genes and loci are beleived to be involved in this disease. Recent studies have reported a strong genetic association between DTNBP1 (dystrobrevin-binding protein 1) gene variants and schizophrenia. Methods: In this research, we used a case-control study to establish the possible association between the P1635 (rs3213207) polymorphism in the DTNBP1 gene and schizophrenia in an Iranian cohort of 200 unrelated patients and 200 controls. The allele and genotype frequencies of the polymorphism in the two groups were determined using PCR-RFLP and the data analyzed using logistic regression and Mantel-Haenszel chisquare tests. Results: The additive effect of the P1635 polymorphism in DTNBP1 and the previously reported G1001C polymorphism in the GRIN1 gene were investigated. Analysis of data revealed a strong association between the P1635 polymorphism and schizophrenia (AG genotype: OR=0.39, 95% CI= 0.24-0.62, P<0.001). Conclusion: Our results indicated that the coexistence of the A and C alleles from the two polymorphisms, P1635 and G1001C, increase the risk for schizophrenia.