Significantly increased transmission of IL-1Ra 4-repeat allele and decreased transmission of 2-repeat allele of a variable number tandem repeat polymorphism to ADHD-affected children was reported by Segman et al.51 Further, immune dysregulation is supported by the finding that ADHD individuals have four times higher concentrations of Interleukins (IL-1 and IL-6) than typically developing children52. Here, IL6 is linked to attention deficit-hyperactivity disorder.