Abstract Background Autism spectrum disorder (ASD) is a common neurodevelopmental disorder characterized by impairment in social interaction, and communication skills, along with restricted or repetitive behaviors. The diagnosis of ASD depends on behavioral parameters. Numerous studies have reported immune system abnormalities and proposed a potential role of autoimmunity in the pathogenesis of ASD. This study aims to assess the correlation between specific cytokines, such as interleukin-6 (IL-6), and particular IL-6 polymorphisms, including IL-6-174G/C (rs1800795) gene polymorphism, IL-6–572 C/G (rs1800796) gene polymorphism and IL-6-597G/A (rs1800797) gene polymorphism among children with ASD. Methods The current study included 100 children with ASD were recruited during their regular follow up to Pediatric Neuro-Psychiatry Clinic of Minia University Hospital of Children. They diagnosed according to DSM-5 ASD criteria. A another 100 children were recruited as control group by simple randomly selected school (pre & elementary school) in Mina Governate, Upper Egypt, their ages and sex matched with the ASD children, they were apparently neuropsychiatric and developmentally normal and free from any chronic systemic illness. The participants were assessed for serum IL-6 levels and single-nucleotide changes in IL-6-174G/C, IL-6–572 C/G and IL-6-597G/A gene polymorphisms. Results The prevalence of the GG genotype and G allele of the IL-6-174G/C gene polymorphism was significantly higher in ASD patients compared to healthy control (P value = 0.0002, 0.03 respectively). In contrast, the GC genotype and C allele of IL-6 -174G/C gene polymorphism were significantly elevated in the control group compared to children with ASD, indicating a protective role against ASD in the Egyptian population. The prevalence of the CG genotype, GG genotype, and G allele of the IL-6–572 C/G gene polymorphism was significantly higher in ASD patients compared to control individuals, indicating an increased risk of ASD within the Egyptian population. The IL-6-597G/A gene polymorphism analysis revealed no significant differences between the two groups in GG and GA genotypes or allelic frequencies. Nevertheless, the AA genotype was only found in the autistic group. Furthermore, ASD patients exhibited significantly higher serum levels of IL-6 than the healthy controls. The GG genotype distribution of IL-6-174G/C gene polymorphism was significantly associated with increased serum levels of IL-6. Conclusion The IL-6 (-174G/C) gene polymorphism (GG genotype) was associated with ASD. Moreover, the (CG + GG) genotypes of IL-6–572 C/G gene polymorphism were associated with ASD, and the (AA genotype) of IL-6-597G/A gene polymorphism was detected only in ASD. This indicates their role in the increased incidence of ASD among the Egyptian population. In addition, IL-6 serum level was significantly elevated in ASD.
Abdullah et al. (Sat,) studied this question.