An association between a functional variant of tumor necrosis factor-alpha (TNF-α) gene and schizophrenia was reported. In the present study, the authors investigated this variant in 186 patients with schizophrenia, 161 patients with bipolor disorder and 657 controls. The TNF-α gene variant did not present a significant difference between the bipolar and control groups. However, a significant increase in frequency of TNF2 allele and of homozygous geneotype in the schizophrenic group was observed. The results support a role for the TNF-α locus in the susceptibility for schizophrenia.