A type of arthritis that occurs among some patients affected by juvenile chronic, or idiopathic, arthritis and characterized by severe extraarticular symptoms that include a spiking fever with a corresponding increase in the serum levels of INTERLEUKIN-6, UVEITIS; LYMPHADENOPATHY; HEPATOSPLENOMEGALY; SEROSITIS and MYALGIA. Polymorphisms in the IL6 and MIF genes are associated with susceptibility to this disorder. OMIM: 604302
