1. University of Groningen, University Medical Centre Groningen, Department of Neurology; Groningen the Netherlands
2. Ommelander Ziekenhuis Groningen, Department of Neurology, Delfzijl and Winschoten; the Netherlands
3. Department of Neurology; Leiden University Medical Centre; Leiden the Netherlands
4. Department of Neurology; Haga Teaching Hospital; The Hague the Netherlands
5. Movement Disorders Unit, Department of Neurology, Westmead Hospital & Sydney Medical School; University of Sydney; Sydney Australia
6. University of Groningen, University Medical Centre Groningen, Department of Laboratory Medicine; Groningen the Netherlands
7. University of Groningen, University Medical Centre Groningen, Department of Genetics; Groningen the Netherlands
8. MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences; Cardiff University; Cardiff United Kingdom
9. Département de Neurologie, AP-HP, Hôpital Pitié-Salpêtrière and Sorbonne Universités, Université Pierre and Marie Curie, Institut du Cerveau et de la Moelle épinière; Paris France
10. Radboud University Medical Centre, Department of Paediatric Neurology; Nijmegen the Netherlands
11. VU University Medical Centre, Department of Child Neurology and Neuroscience Campus Amsterdam; Amsterdam the Netherlands
12. University of Groningen, University Medical Centre Groningen, Department of Paediatrics; Groningen the Netherlands