Investigation of cytochrome B mutations, and UCP2 and STC1 gene expressions in patients with bipolar disorder.

Objective: The aim herein was to investigate mitochondrial cytochrome B (MT-CYB) mutations in individuals with bipolar disorder. Stanniocalcin-1 ( STC1 ) and uncoupling protein 2 ( UCP2 ) mRNA expressions and their relationship with clinical data and each other were also investigated.

Method: The blood samples of 100 individuals were included in this study. Real-time PCR was used to evaluate mRNA expressions of STC1 and UCP2 . Genetic alterations were investigated via Sanger DNA sequencing. An in silico analysis was performed to reveal the phenotypic effects of MT-CYB mutations.

Results: In the MT-CYB gene of the bipolar disorder patients, the most seen mutations were the T194A A>G mutation at position 1532, G deletion at position 15498, and C>A L236I mutation at position 15452. Most of the mutations appeared to be neutral or benign. The UCP2 and STC1 mRNA expression levels were significantly higher in the patients than in the healthy controls ( P  = 0.0124 and P  < 0.0001, respectively). The area under the curve values of the receiver operating characteristic curve analysis for UCP2 and STC1 were 0.6631 ( P  = 0.0123) and 0.8059 ( P  < 0.0001), respectively. No significant relationship was observed between the gene expressions and the routine laboratory findings. There was a positive correlation between the UCP2 and STC1 mRNA expressions in the bipolar disorder patients ( r  = 0.03559, P  = 0.0306).

Conclusion: Expression of UCP2 and STC1 may be important parameters in bipolar disorder. MT-CYB mutations may be related to gene expressions. Comprehensive studies on bipolar disorder will help better understand UCP2 and STC1 gene functions.