Impact of IL-1 receptor antagonist gene polymorphism on schizophrenia and bipolar disorder

Abstract

OBJECTIVES:

Variable levels of cytokines were observed in patients with schizophrenia and bipolar disorder, and an especially high level of interleukin-1 (IL-1) was detected in schizophrenia patients. It is known that IL-1 receptor antagonist (IL-1RA) binds to IL-1 receptors and inhibits the receptor binding of IL-1alpha and IL-1beta.

METHODS:

In this study, the association between the variable number of tandem repeats polymorphism of the IL-1RA gene and schizophrenia (n=269) and bipolar disorder (n=83) was investigated.

RESULTS:

The genotype distribution and allele frequency were significantly different between schizophrenic patients and the control group (P<0.05); however, there were no prominent differences between bipolar patients and the control group. The carriage rate for the IL1RN*2 allele was associated with higher risk of schizophrenia (odds ratio=2.24).

CONCLUSIONS:

This study indicates that IL-1RA could be a candidate gene for susceptibility to schizophrenia.

Psychiatric Genetics 2004, 14:165–167 Keywords: cytokine, interleukin-1 receptor antagonist, schizophrenia, bipolar disorder, polymorphism