1. Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710.
2. University Pierre and Marie Curie–Paris 6, 75005 Paris, France.
3. Genethon, 910020 Evry, France.
4. Department of Pediatrics, New Jersey Medical School, Rutgers University, Newark, NJ 07103.
5. Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom.