Polymorphism of interleukin-1 and interleukin-1 receptor antagonist genes in children with autism spectrum disorders

In this study, we first investigated interleukin-1 beta (IL-1 beta) and IL-1 receptor antagonist (IL-1RA) levels in a cohort of Egyptian children with autism spectrum disorder (ASD) and in healthy controls. Second, we examined the single-nucleotide polymorphisms (SNPs) at positions -31 and - 511 of the IL-1 beta gene promoter and IL1RA and assessed the association between IL1B and IL1RA polymorphisms with ASD. We examined IL1 beta promoter polymorphism at -511 (IL-1 beta-511) and - 31 (IL-1 beta-31) and IL1RA gene polymorphism in 80 children with ASD and 60 healthy children. The children with ASD had significantly higher levels of IL-1 beta and IL-1RA than the controls. The children with ASD also had significantly higher frequencies of homozygous (CC) and heterozygous (TC) genotype variants of IL-1 beta-511, and IL-1RA than the controls. Moreover, the frequency of the IL-1 beta-511 allele (C) was higher in the ASD group than in the controls (p = .001). The homozygous and heterozygous variants of IL-1RA allele II were also significantly higher in the ASD group than in the control group. There was no significant association between the IL-1 beta-31 genotype and autism classes. However, there were significant differences in the distribution of the IL-1RA heterogeneous genotype and allele II among children with severe autism. The inflammatory role of cytokines has been implicated in a variety of neuropsychiatric pathologies, including autism. Our data show alterations in the IL-1 beta system, with abnormally increased serum levels of IL-1 beta and IL-1RA in the children with ASD. Further, polymorphisms in the IL-1 beta-511 and IL-1RA genotype variants correlated positively with autism severity and behavioral abnormalities. IL-1 beta-511 and IL-1RA gene polymorphisms could impact ASD risk and may be used as potential biomarkers of ASD. Variations in the IL-1 beta and IL-1RA systems may have a role in the pathophysiology of ASD.