Association of P1635 and P1655 polymorphisms in dysbindin (DTNBP1) gene with schizophrenia

Schizophrenia (SCZ) is a severe psychiatric disorder with a lifetime prevalence of approximately 1% in most of the populations studied. SCZ is multifactorial with the contribution of multiple susceptibility genes that could act in conjunction with epigenetic processes and environmental factors. There is some evidence supporting the association between genetic variants in dysbindin (DTNBP1) gene and SCZ in populations. In this study, we investigated the association between polymorphisms P1635 and P1655 in dysbindin gene with SCZ.

Totally, 115 unrelated patients with SCZ and 117 unrelated healthy volunteers were studied. Genomic DNA was extracted from blood. Genotyping was done with the PCR-RFLP method. The allele and genotype associations were analysed with X 2 test. The Benjamini-Hochberg procedure was used to correct p values for multiple comparisons.

The results showed no significant difference between patients and controls in allelic frequencies or genotypic distributions of SNP P1635 (p = 0.809), but a significant difference between the case and control groups for SNP P1655 (p = 0.009) was found. We could also find a significant positive association between A-C haplotype and SCZ (OR = 1.7, 95% CI 1.18-2.42; p = 0.004, p c = 0.02) and a protective effect for A-G haplotype (p = 0.003, OR = 0.57, 95% CI 1.18-2.42; p = 0.003, p c = 0.02).

This study may provide further support for the association between SNP polymorphisms in DTNBP1 and SCZ in the Iranian population. Studies with more markers and subjects for various populations will be necessary to understand the genetic contribution of the gene to the development of SCZ.