Analysis of a polymorphism in the promoter region of the tumor necrosis factor alpha gene in schizophrenia and bipolar disorder: further support for an association with schizophrenia.

Activation of the inflammatory response system has been observed in the schizophrenia and affective disorders. Investigations of the role of the inflammatory response in these psychiatric disorders include analysis of the immune mediators at the gene level, so the genetic polymorphism of specific cytokine loci has been investigated in psychiatric disorders. In the present investigation, researchers performed cross-sectional study to verify whether the G308A gene polymorphism was associated with a predisposition to schizophrenia or bipolar affective disorder (BPAD) in a Brazilian sample. A total of 657 controls were randomly recruited from unrelated subjects admitted to a routine checkup outpatient clinic. Results showed an association between the G308A TNF-α polymorphism and schizophrenia.