Evaluation of 45bp Ins/Del Genetic Variant inUCP-2 Gene as a Risk factor for Bipolar Disorder

Bipolar disorder is a type biphasic disorder of energy availability that indicates increased mitochondrial respiration in episodes of mania, compared to decreased mitochondrial function in the depressive phase of the illness. Mitochondrial dysfunction may lead to an excessive increase in reactive oxygen species (ROS). The UCP-2 proteins act as regulators of ROS in the cell. This study aimed to investigate the association of UCP-2 45bp ins/del genetic variant with susceptibility to bipolar disorder.

This case-control study was performed on 205 subjects with bipolar disorder and 200 healthy subjects as a control group. After extraction of DNA from peripheral blood samples, genotype determination was performed using the PCR method. Moreover, the logistic regression analysis was used for the comparison of genotypes and allele frequencies between case and control groups.

There was a significant association between ID (OR=0.42; 95% CI= 0.27-0.64; P<0.001) and II (OR=0.39; 95% CI=0.20-0.77; P=0.006) genotypes with bipolar disorder. Data analysis showed I allele had a protective effect on susceptibility to bipolar disorder (OR=0.56; 95% CI=0.42-0.75; P<0.001).

This study investigated, for the first time, the association between UCP-2 45bp ins/del genetic variant and bipolar disorder. The results showed UCP-2 45bp ins/del genetic variant was associated with bipolar disorder; however, more studies are required to be conducted in different ethnicities to confirm these results.