The Relationship between Interleukin-1beta Gene Polymorphism and Partial Epilepsy

ABSTRACT

BACKGROUND: Neuronal cell death, reactive gliosis, enhanced neurogenesis, and axonal sprouting are well-known pathogenetic mechanisms of epileptogenesis. Pro-inflammatory cytokines are known to modulate the process of epileptogenesis. Interleukin (IL)-1beta-511*2 allele (T at position -511) is associated with increased production of ILs. Symptomatic partial epilepsy (SPE) has not been traditionally regarded as having a major genetic contribution, but recent studies suggest the possibility of genetic predisposition to SPE. In humans, the relationship between SPE and genetic predisposition is not well known. We hypothesized that the IL-1beta gene promoter polymorphism may be a genetic predisposition to SPE in humans. METHODS: Genomic DNA was extracted from peripheral blood leukocyte of consecutive 164 epilepsy patients and 230 normal controls. A single base pair polymorphism at position -511 in the promoter region of the IL-1beta gene was analyzed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Ninety-four patients had partial epilepsy and were divided into SPE and cryptogenic partial epilepsy (CPE). RESULTS: Forty patients had SPE and 63% of SPE showed structural lesions on MRI. The frequency of homozygote for IL-1beta -511*2 allele was significantly higher in SPE than in controls and CPE [45% (18/40) in SPE vs. 23% (54/230) in controls, p=0.01, and 45% in SPE vs. 28% (15/54) in CPE, p=0.02]. CONCLUSIONS: The IL-1beta -511 polymorphism may be related to the genetic predisposition of SPE.