Assessment of Brain-Derived Neurotrophic Gene and its Polymorphism Frequency in Patients With Bipolar Disorder in Hamadan

Abstract

Background: Bipolar disorder is a biological brain disorder which is associated with debilitating fluctuation in mood and adverse eects on patients, their families and society. The importance of genetics and its role in bipolar disorder is a controversial issue to discuss. Evidence indicates a relation between the risk of bipolar disorder and specific genes. Amongst the genes whose role has been established in bipolar disorder, the most notable gene is BDNF (Brain-derived neurotrophic factor). Methods: The study is based on a case-control methodology. During 18 months, the blood samples of patients diagnosed with bipo- lar mood disorder who were admitted to Farshchian hospital of Hamadan from March 2011 to September 2012 and for the control group, the blood samples of patients admitted to other parts of Farshchian hospital except psychiatric ward were taken and DNA extraction from white blood cells was performed. In general, 84 patients and 85 controls were examined in this study and an ex- pert in vials containing EDTA anticoagulant collected 4ml of blood samples. These samples were sent to the molecular biology lab of Hamadan University of Medical Science to determine their genetic polymorphisms. Genomic DNA was extracted from periph- eral blood cells using the real extraction DNA kit (DNP Tm kit, Cat# DN8115C, CinnaGen co., Iran). The allele specific polymerase chain reaction technique was used to determine the frequencies of listed genotype. Considering the dierent variations for each gene, primers design was carried out using the Allele ID software (Allele ID 6, premier Bio soft Int, USA). For this purpose, 401 nu- cleotide sequences of targeted gene polymorphisms was chosen as the control sequence and desired primers for this sequence was designed and ordered (Takapouzist Co., Iran). Finally, using the mentioned method the sequences were amplified and examined on 2% agarose gel during electrophoresis. The young mania rating scale (YMRS) was used to evaluate manic symptoms. A written consent was obtained from each individual patient during the study. In addition, all patients in this study were anonymous and ethical considerations were taken into account. Statistical data analysis was performed using SPSS Software and Chi-square test was used to analyze their significance. Results: The results of this study, which was conducted on 84 patients in the case group and 85 patients in the control group indi- cated that the frequencies of evaluated alleles in the case and control groups for AA genotype were 4 and 4, for GA genotype were 23 and 28, and for GG genotype were 53 and 53, respectively. Conclusions: According to the obtained data, there is no significant relationship between genetic and bipolar disorder. Some stud- ies in this field have also confirmed this issue.