Jürgen W. Spranger, M.D., is Professor Emeritus of Pediatrics, Children's Hospital, University of Mainz, Mainz, Germany and Senior Genetics Scholar, Greenwood Genetic Center, Greenwood, SC. Paula W. Brill, M.D., is Professor Emerita of Radiology, Weill Cornell Medical College New York, NY, and former Chief of Pediatric Radiology, New York Presbyterian Hospital. Christine Hall, M.D., is Professor of Pediatric Radiology, University College London and formerly Consultant Pediatric Radiologist, Great Ormond Street Hospital for Children, London, UK. She is currently an Honorary Consultant, St George's, University of London. Gen Nishimura, M.D., is Visiting Professor at the Center for Intractable Disease, Saitama Medical University Hospital, and former Radiologist-in-Chief, Department of Pediatric Imaging, Tokyo Metropolitan Children's Medical Center. Andrea Superti-Furga, M.D., is Professor of Pediatrics and Genetics at the University of Lausanne and Head of the Division of Genetic Medicine, Lausanne University Hospital, Lausanne, Switzerland. Sheila Unger, M.D., is Privat-docent at the University of Lausanne, Senior Geneticist at the Division of Genetic Medicine, Lausanne University Hospital, Lausanne, Switzerland, and formerly Coordinator at the European Skeletal Dysplasia Network.