1. Department of Neurology and Clinical Neurophysiology University of Groningen, University Medical Center Groningen Groningen The Netherlands
2. Expertise Center Movement Disorders Groningen University Medical Center Groningen (UMCG) Groningen The Netherlands
3. Department of Gastroenterology and Hepatology University of Groningen, University Medical Center Groningen Groningen The Netherlands
4. Department of Neurology and Clinical Neurophysiology University of Amsterdam, Amsterdam University Medical Center Amsterdam The Netherlands
5. Department of Neurology and Clinical Neurophysiology Canisius Wilhelmina Hospital Nijmegen The Netherlands
6. Department of Genetics University of Groningen, University Medical Center Groningen Groningen The Netherlands
7. Department of Pediatrics Clinical Sciences, Lund University Lund Sweden