Natural History, Genetics, and Pathophysiology of Systemic Juvenile Idiopathic Arthritis, Adult-Onset Still's Disease, and Related Conditions

The purpose of this protocol is to study the natural history, genetics and pathophysiology of systemic juvenile idiopathic arthritis (sJIA), adult-onset Still s disease (AOSD) and related inflammatory conditions. One of seven subtypes of juvenile idiopathic arthritis (JIA), sJIA contributes disproportionately to the morbidity and mortality of JIA and is considered by many to be the most severe JIA subtype. sJIA typically presents with fever of unknown origin and arthritis, together with evanescent skin rash, serositis, hepatosplenomegaly and lymphadenopathy. It is strongly associated with macrophage activation syndrome (MAS), which has a high fatality rate when untreated. AOSD is phenotypically similar to sJIA in presentation, progression and association with MAS, however it develops after the 16th birthday. The causes sJIA and AOSD are poorly understood. sJIA and AOSD are diagnoses of exclusion and there are often delays in their diagnosis due to the stringency of their classification criteria. There is no diagnostic test for sJIA/AOSD and there exists significant overlap with other conditions. The manifestations and severity of disease can differ among patients, further delaying the diagnosis. There is also considerable variability in both patient response to therapy and long-term outcomes, and there exist no therapeutic or prognostic biomarkers to guide treatment. Given our limited understanding of the causes, treatments and prognostic factors of sJIA, we developed this protocol to longitudinally follow patients with sJIA/AOSD and investigate these topics. The specific goals of this protocol include: 1) Establishing a cohort of patients with sJIA/AOSD and assembling a detailed set of longitudinal clinical information; 2) Identifying genetic factors that cause or influence susceptibility to sJIA/AOSD; 3) Determining the functional relevance of genes and variants that influence sJIA/AOSD; and 4) Developing a molecular library of patient biological samples which may be used to further investigate sJIA/AOSD. Patients enrolled in this protocol will undergo screening history, physical examination and laboratory evaluation. At times, we may ask for permission to evaluate additional family members. We will collect peripheral blood samples for genetic and functional studies from affected patients, unrelated healthy volunteers and in some cases patients family members. We will ask permission to perform whole genome/exome sequencing. We also may ask some patients to undergo skin biopsy for research purposes. This study aims to elucidate genetic factors that contribute to sJIA/AOSD and related conditions and to determine their implications on inflammatory pathophysiology. By so doing, we hope to identify novel therapeutic targets for inflammatory disease.