Preliminary investigation of two promoter region polymorphisms of the TNFA gene in patients with recurrent depressive disorder

Immune system dysregulation plays a role in the pathogenesis of complex human diseases, including psychiatric disorders. In addition, elevated levels of pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α) may be conditioned by the presence of specific polymorphic variants. The present case-controlled preliminary study evaluated the prevalence of TNFA gene single nucleotide polymorphisms (SNPs) G-308A (rs1800629) and T-1031C (rs1799964) in 83 Polish patients with depression by restriction fragment length polymorphism analysis. The results were compared with the frequencies of genotypes in a geographically- and ethnically-matched group of individuals without depression. No statistically significant difference in genotype/allele frequency was observed for either SNP between the two groups. No association was found between the particular genotypes and selected demographic/clinical features, including sex, age at diagnosis or severity of depressive symptoms before/after pharmacotherapy. Thus, there does not appear to be any connection between the studied SNPs and the development and progression of depression; however, further studies are required with larger cohorts to better understand this aspect of depression.