By James T. Cassidy, MD, Professor of Child Health; Chief, Division of Pediatric Rheumatology, Department of Child Health, University of Missouri Health Sciences Center and Children's Hospital, Columbia, MO; and Ross E. Petty, MD, PhD, FRCPC, Professor of Pediatrics, University of British Columbia; Head, Division of Rheumatology, Department of Pediatrics, British Columbia Children's Hospital, Vancouver, British Columbia, Canada |