Upregulation of vitamin D-related genes in schizophrenic patients

Low level of vitamin D is a potential risk factor for developing schizophrenia. Through interaction with its receptor (VDR) and the related enzymes (CYP27B1, CYP24A1), vitamin D modulates neurodevelopment, neuroprotection, and immunomodulation. Its deficiency leads to aberrant neurodevelopment in schizophrenic patients.

In this case-control study, relative expression of VDR, CYP27B1, and CYP24A1 in schizophrenic patients was compared with healthy individuals. Total RNA was extracted from whole blood of 50 patients with schizophrenia and 50 healthy controls. Real-time PCR was used to determine relative gene expression levels of VDR, CYP27B1, and CYP24A1.

Significant upregulations were observed in VDR (P=0.004, 95% CI=0.77, 0.86), CYP27B1 (P=0.002, 95% CI=1.22, 4.98), and CYP24A1 (P≤0.0001, 95% CI=-2.721, 1.061) expressions in peripheral blood of schizophrenic patients compared with controls. Moreover, the gender-based analysis revealed upregulation of all genes in all the categories of male and female except for VDR gene in male group (P=0.234, 95% CI=-0.79, 3.35) and CYP27B1 gene in the female group (P=0.09, 95% CI=-0.21, 6.55). The age-based analysis demonstrated overexpression of VDR and CYP27B1 genes in all categories. Finally, there were significant correlations between expression levels of all genes (P<0.0001), while no correlation was found between age and expression of genes.

We hypothesized that the observed upregulation of the mentioned genes in schizophrenia patients might be the result of a compensatory mechanism to protect the affected individuals against adverse consequences of this disorder. Such imbalance in vitamin D processing pathway might also be implicated in the pathogenesis of schizophrenia. However, future studies should be designed to confirm the results of the current study.