Association between TNF-α promoter −308A/G polymorphism and tardive dyskinesiain Chinese Han patients with schizophrenia

ObjectivePrevious studies have indicated that the immune may be involved in the pathogenesis of tardive dyskinesia (TD). Some genetic polymorphisms in the human leukocyte antigen (HLA) I and II regions have been associated with TD, and the tumor necrosis factor-α (TNF-α) gene is located in the HLA III region. TNF-α levels in the striatum significantly increased in haloperidol-induced TD in rats. The TNF-α gene −308A/G single nucleotide polymorphism (SNP) has been shown to directly influence TNF-α expression. The genetic association between the TNF-α gene −308A/G SNP and TD is unclear. The present study investigated whether this variation is associated with clinical phenotypes and TD in schizophrenia in a genetically homogeneous northern Chinese Han population.MethodsWe genotyped the TNF-α gene −308A/G SNP in patients with schizophrenia with TD (n = 350) and without TD (n = 410). The Abnormal Involuntary Movement Scale (AIMS) and Positive and Negative Syndrome Scale (PANSS) were used to assess the severity of TD and psychopathology of schizophrenia, respectively.ResultsThe allele and genotype frequencies did not significantly differ between patients with schizophrenia with and without TD (p > 0.05). No significant difference was found in the total AIMS score between the genotypes (p > 0.05). However, the PANSS negative symptom subscore was associated with risk for TD (p = 0.004), and a significant difference was found in total AIMS score between the genotypes in TD patients (p = 0.013).ConclusionThe TNF-α gene −308A/G polymorphism does not appear to play a major role in the susceptibility to TD in patients with schizophrenia in a northern Chinese Han population. However this polymorphism may play a role in the TD severity.

► Older age, male, and PANSS negative symptoms were major risk factors for TD. ► No significant association between TD and the TNF-α -308A/G SNP. ► No significant difference of AIMS scores between the two genotypes in TD patients.