Polymorphisms for interleukin 1β exon 5 and interleukin 1 receptor antagonist in Taiwanese children with febrile convulsions

Objective: To investigate whether interleukin 1beta (IL-1beta) exon 5 and IL-1 receptor antagonist (IL-1Ra) gene polymorphisms can be used as markers of susceptibility to febrile convulsions in children. Methods: Children were divided into 2 groups: those with febrile convulsions (group 1; n = 51) and normal control subjects (group 2; n = 83). Polymorphisms for IL-1beta exon 5 and IL-1Ra gene polymorphisms were detected by polymerase chain reaction. Genotypes and allelic frequencies for IL-1beta exon 5 and IL-1Ra gene polymorphisms in both groups were compared. Results: Genotype and allele frequencies for IL-1beta exon 5 in both groups were not significantly different. Proportions of E1 homozygotes and E1/E2 heterozygotes for IL-1beta exon 5 were 50 (98.1%) and 1 (1.9%), respectively, in group I and 82 (98.8%) and 1 (1.2%), respectively, in group 2. Frequencies of alleles E1 and E2 for IL-1beta exon 5 were 101 (99.0%) and 1 (1.0%), respectively, in group 1 and 165 (99.4%) and 1 (0.6%), respectively, in group 2. Genotype proportions and allele frequencies for IL-1Ra between groups were significantly different. Proportions of genotypes I/I and I/II for IL-1Ra were 49 (96.1%) and 2 (3.9%) in group 1 and 69 (83.1%) and 14 (16.9%) in group 2. Frequencies of alleles I and 11 for IL-1Ra were 100 (98.0%) and 2 (2.0%) in group I and 152 (91.6%) and 14 (8.4%) in group 2. Conclusions: The IL-1Ra allele I is associated with a higher susceptibility to febrile convulsion, which may become a useful marker for predicting the development of febrile convulsions. The IL-1beta exon 5 gene polymorphisms are not a useful marker for predicting the susceptibility to febrile convulsions.