1 Movement Disorders Program, Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
2 Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
3 Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.
4 Children's Hospital at Westmead Clinical School and Kids Neuroscience Centre, Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Westmead, New South Wales, Australia.
5 Movement Disorders Unit, Pediatric Neurology Department, Institut de Recerca, Hospital Sant Joan de Déu Barcelona, Barcelona, Spain.