Association of IL4 single-nucleotide polymorphisms with febrile seizures.

As of importance of interleukin-4 (IL-4) in inhibiting the production of proinflammatory cytokines, the IL4 gene polymorphisms were investigated in patients with febrile seizure. This association has not been investigated yet, except 1 study which has been done in Japanese population. Eighty-two patients with febrile seizure were enrolled in this study, compared with 139 controls. The allele and genotype frequency of 3 single-nucleotide polymorphisms of IL4 gene were determined. Frequency of the IL4-590/C allele in the patient group was significantly higher than in the control group (P < .0001). Frequency of the following genotypes was significantly lower in patients compared to controls: IL-4 (-590) TC (P = .0001) and IL-4 (-33) TC (P = .001). The most frequent IL-4 haplotype in the patient group was TCC (P = .00) haplotype. In contrast, frequencies of GCC (P = .01), TTT (P = .009), and TTC (P = .0007) haplotypes were significantly lower in febrile seizure patients. Certain alleles, genotypes, and haplotypes in the IL4 gene were overrepresented in Iranian patients with febrile seizure, which could predispose individuals to this disease, and further investigations in other ethnicities are required.