The relationship between TNF-α gene polymorphism rs1800629 and negative symptoms factors in schizophrenia

Abstract

Background. Schizophrenia is characterized by a significant heterogeneity of symptoms. This fully applies to negative symptoms (NS), the heterogeneity of which, according to modern concepts, is determined by various neurobiological mechanisms. A widespread model of NS provides two factors (subdomains) in the structure of NS: abulia-apathy (AA) and expressive deficit (ED). Immunological studies have shown that the concentration of the pro-inflammatory cytokine TNF-α is differentially associated with NS subdomains. Objective. To investigate the relationship between NS factors and the TNF-α polymorphism rs1800629G/A. Methods. The sample for genotyping included 541 people. The severity of NS was determined by the Positive and negative syndromes scale (PANSS). PANSS symptoms were included into subdomains in accordance with the previously proposed approach. Genotypes were determined by PCR. Results. Differences in the severity of symptoms of the ED factor depending on the genetic variant rs1800629 were revealed (p=0.035). In patients with two copies of the A allele, which has a higher transcriptional activity, the severity of ED symptoms was higher than in the G allele carriers (22.8±4.7 versus 19.2±5.9 points). No significant effect of genotype on factor AA was found. Conclusion. The discovery of a differentiated relationship between TNF-α rs1800629 polymorphism and NS is consistent with the data of immunological studies, and also confirms the assumption of various biological mechanisms that determine the heterogeneity of schizophrenia NS.