Background: Alterations in cytokine levels in patients with schizophrenia have been documented. Polymorphisms in these cytokine genes are thus potential genetic markers for schizophrenia. The aim of this study was to investigate four biallelic polymorphisms in the tumor necrosis factor-alpha (TNFalpha) gene promoter in relation to susceptibility to schizophrenia.
Methods: Three hundred two patients and 152 control subjects were genotyped and frequencies of genotypes and alleles were compared for the -1031T/C, -863C/A, -857C/T, and -308G/A polymorphisms. Genotype and allele frequencies were compared between controls and patients.
Results: There were statistically significant differences in genotype distribution and allele frequencies for the -308 polymorphism (p <.001). Genotype distribution and allele frequencies of the other three polymorphisms were not different between patients and reference controls.
Conclusions: The -308 polymorphism or another genetic variant in linkage disequilibrium with it could be a susceptibility factor for chronic schizophrenia.