1. Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
2. The University of Sydney & Children's Hospital at Westmead Sydney Australia
3. Carver College of Medicine, Department of PediatricsUniversity of Iowa Iowa City, Iowa USA
4. IRCCS FoundationCarlo Besta Neurological Institute Milan Italy
5. UCL Institute of Child Health & Great Ormond Street Hospital London United Kingdom
6. MRC Centre for Neuromuscular DiseasesUCL Institute of Neurology Queen Square, London United Kingdom
7. Neuromuscular Program, Division of NeurologyNemours Children's Hospital Orlando Florida USA
8. Department of NeurologyUniversity of Rochester Rochester New York USA
9. Department of Biostatistics and Clinical EpidemiologyPerelman School of Medicine, University of Pennsylvania Philadelphia Pennsylvania USA
10. Carver College of Medicine, Department of NeurologyUniversity of Iowa Iowa City, Iowa USA
11. Children's Hospital of Philadelphia, Department of NeurologyPerelman School of Medicine, University of Pennsylvania Philadelphia Pennsylvania USA