1 Faculty of Medicine (S.M.D., D.P.), University of Ottawa, ON, Canada; Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics (G.B.), McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center; MyeliNeuroGene Laboratory (G.B.), Research Institute of the McGill University Health Center, Montreal, Quebec, Canada; Department of Pediatric Neurology (N.I.W.), Emma Children's Hospital, Amsterdam, Netherlands; Amsterdam Neuroscience (N.I.W.), Vrije Universiteit, Netherlands; and Department of Medical Imaging (E.M.) and Division of Neurology (D.P.), CHEO, University of Ottawa, ON, Canada.