1 University of Groningen, University Medical Centre Groningen, Department of Neurology, Groningen, the Netherlands.
2 Ommelander Ziekenhuis Groningen, Department of Neurology, Scheemda, 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 Medisch Spectrum Twente, Department of Neurology, Enschede, the Netherlands.
6 Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Cardiff, United Kingdom.
7 Movement Disorders Unit, Department of Neurology, Westmead Hospital & Sydney Medical School, University of Sydney, Sydney, Australia.
8 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.
9 University of Groningen, University Medical Centre Groningen, Department of Health Sciences, Community and Occupational Medicine, Groningen, the Netherlands.
10 Radboud University Medical Centre, Amalia Children's Hospital, Department of Pediatric Neurology, Nijmegen, the Netherlands.
11 Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam and Amsterdam Neuroscience, Amsterdam, the Netherlands.
12 University of Groningen, University Medical Centre Groningen, Department of Genetics, Groningen, the Netherlands.
13 University of Groningen, University Medical Centre Groningen, Department of Pediatrics, Groningen, the Netherlands.