sJIA is a rare form of the disease (10% of JIA) with systemic symptoms such as arthralgia, fever, evanescent rash, and a major biological inflammatory syndrome with neutrophilic polynuclear leukocytosis, elevated C-reactive protein (CRP), and hyperferritinemia, reflecting hypercytokinemia IL-1; notably, it has been shown to play an important role in the pathogenesis of sJIA and at a lower degree in other forms of JIA, since blocking IL-1 using the recombinant form of the IL-1 receptor antagonist or anti-IL-1β monoclonal antibody is an efficient strategy (1, 2). The gene discussed is IL1B; the disease is isolated hyperferritinemia.