Association between promoter polymorphisms of the LIFR gene and schizophrenia with persecutory delusion in a Korean population.

Schizophrenia has been associated with an imbalance in inflammatory cytokines. Leukemia inhibitory factor receptor α (LIFR) is an integral component of the glycoprotein 130-LIFR signaling complex, which participates in signal transduction by members of the interleukin (IL)-6 cytokine family. The aim of this study was to investigate whether genetic polymorphisms of the LIFR gene are associated with schizophrenia in the Korean population. We also explored possible associations between the polymorphisms and the clinical symptoms of schizophrenia. We selected three single nucleotide polymorphisms (SNPs) (rs2071237 -200C/G, rs2071236 -254C/T and rs6862038 -962A/G) on the promoter region of the LIFR gene and recruited 204 schizophrenia patients and 367 control subjects from the Korean population. All patients were evaluated according to the Operational Criteria Checklist for Psychotic Illness. SNP genotyping was performed by direct sequencing. An analysis of multiple logistic regression models (co-dominant 1, co-dominant 2, dominant, recessive and overdominant) was performed to evaluate odds ratios (ORs), 95% confidence intervals (CIs) and p-values. No significant difference was revealed between schizophrenia patients and controls. However, a significant association was detected between the LIFR gene polymorphisms and schizophrenia patients with persecutory delusion (rs2071236, OR=2.18, 95% CI=1.20-3.94, P=0.009 in the overdominant model; rs6862038, OR=2.08, 95% CI=1.16-3.74, P=0.013 in the overdominant model). The present study suggests that the LIFR gene may be related to schizophrenia with persecutory delusion in the Korean population.