TNF-α-308 G/A variant may be associated with bipolar disorder in a Turkish population

ABSTRACT Background: Tumor necrosis factor alpha (TNF-α) is a proinflammatory multifunctional cytokine produced by macrophages. A dysregulation of the immune system contribute to the pathogenesis of bipolar disorder (BD). In this study, we aimed to investigate the relationship between the TNF-α gene -308G/A promoter variant and the risk of BD. Methods: A total of 104 BD patients and 94 healthy controls were enrolled in the study. Genomic DNA was isolated and TNF-α -308G/A variant was analyzed using PCR-RFLP method. Results: TNF-α -308G/A variant GG genotype and G allele were more prevalent in BD patients compared to the controls (p = 0.002 and p = 0.017, respectively). The patients carrying GG genotype had a 5.927-fold higher risk of developing BD. Then, we divided patients into two groups as smokers and non-smokers. TNF-α -308G/A variant GA genotype was higher in non-smoker BD patients than smoker patients (p = 0.027). We found that TNF-α -308G/A AA genotype and A allele increased in smoker patients compared to non-smoker patients (p = 0.008, p = 0.002, respectively). Discussion: Our results provided evidence that TNF-α -308G/A variant may contribute to development of BD in a Turkish cohort. In addition, this variant plays a relevant role in the smoker status of BD.

Effect of monoamine oxidase B A644G variant on nicotine dependence and/or schizophrenia risk

Abstract Objectives Schizophrenia (Sch) is a severe and chronic mental illness. Smoking prevalence is higher in patients with Sch than general population. We aimed to investigate the effects of MAOB gene A644G variant on nicotine dependence (ND) and Sch+ND risk in Turkish population and to evaluate by bioinformatic analysis. Methods Present study included 161 individuals with ND, 223 patients with Sch+ND, and 96 non-smoker controls. MAOB A644G variant was analyzed using PCR-RFLP method. As the MAOB gene is located on the X chromosome, each gender was analysed separately. Results The total distributions of AA, AG and GG genotypes of MAOB gene A644G were 44.7%, 22.4% and 32.9% in the ND group, 45.3%, 25.1% and 29.6% in the Sch+ND group and, 44.8, 22.9% and 32.3% in non-smoker controls. No significant differences were observed between groups for the MAOB A644G genotype and allele frequencies when female group compared to male group (p > 0.05). Examination of disease associations of SNPs from each miRNA gene region in GWAS databases yielded results for aging, bipolar disorder, autoimmune, and neurological diseases. Discussion Our results indicate that the MAOB gene A644G variant is not associated with ND and/or Sch susceptibility in the Turkish population.