JIA shows similarities to adult autoimmune diseases, and, indeed, genome-wide association studies identify a strong overlap in the common variants linked to autoimmune susceptibility and JIA susceptibility.1 JIA also has similarities to autoinflammatory diseases, such as genetic associations to innate inflammatory pathways2 and response to IL-1β blockade.3 The recent success in identifying monogenic causes of autoinflammatory diseases4 suggests that monogenic causes may also underlie a subset of patients with JIA. This evidence concerns the gene IL1B and juvenile idiopathic arthritis.