1. Department of Child Neurology and Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
2. Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
3. Department of Clinical Chemistry, VU Medical Center, Amsterdam, The Netherlands
4. Pediatric Neurology, University Children’s Hospital, Heidelberg, Germany
5. Pediatric Neurology and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, and Center for Rare Disorders, Heidelberg University Hospital, Heidelberg, Germany