Affiliation: | 1. Department of Pediatrics, Division of Rheumatology, Children’s Hospital of Philadelphia, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, 2716 South Street, Floor 11, Philadelphia, PA 19146, USA;2. Pediatric Translational Research Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA |