35 (83.3%) patients were diagnosed with JIA (experimental group), median age of 10.6 years (IQR 8.8-12.7), 12 (35.3%) were male and 25 (74.3%) were receiving biological treatment for JIA; 15 patients anti-TNFα (11 etanercept and 4 adalimumab), 4 anti-IL-1R (anakinra) and 6 anti-IL-6R (tocilizumab). This evidence concerns the gene IL6R and juvenile idiopathic arthritis.