Background: Bipolar disorder is a biological brain disorder which is associated with debilitating fluctuation in mood and adverse effects 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 ۱۸ months, the blood samples of patients diagnosed with bipolar mood disorder who were admitted to Farshchian hospital of Hamadan from March ۲۰۱۱ to September ۲۰۱۲ 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, ۸۴ patients and ۸۵ controls were examined in this study and an expert in vials containing EDTA anticoagulant collected ۴ml 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 peripheral blood cells using the real extraction DNA kit (DNP Tm kit, Cat# DN۸۱۱۵C, CinnaGen co., Iran). The allele specific polymerase chain reaction technique was used to determine the frequencies of listed genotype. Considering the different variations for each gene, primers design was carried out using the Allele ID software (Allele ID ۶, premier Bio soft Int, USA). For this purpose, ۴۰۱ nucleotide 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 ۲% 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 ۸۴ patients in the case group and ۸۵ patients in the control group indicated that the frequencies of evaluated alleles in the case and control groups for AA genotype were ۴ and ۴, for GA genotype were ۲۳ and ۲۸, and for
GG genotype were ۵۳ and ۵۳, respectively.
Conclusions: According to the obtained data, there is no significant relationship between genetic and bipolar disorder. Some studies in this field have also confirmed this issue.