1. Department of Clinical Sciences, Neurosciences, Umeå University , 901 87 Umeå , Sweden
2. Department of General Paediatrics, University of Münster , 48149 Münster , Germany
3. Department of Paediatrics, University Medical Centre Hamburg-Eppendorf , 20251 Hamburg , Germany
4. Department of Medical Biosciences, Pathology, Umeå University , 901 85 Umeå , Sweden
5. Clinic for Radiology, University Hospital Münster, WWU University of Münster , 48149 Münster , Germany
6. Starship Children’s Health, Auckland City Hospital , Auckland 1142 , New Zealand
7. Department of Medical Biosciences, Clinical Chemistry, Umeå University , 901 87 Umeå , Sweden
8. Current address: Institute of Human Genetics, University Hospital Heidelberg , 69120 Heidelberg , Germany
9. Department of Paediatric Neurology, University Hospital Essen , 39081 Essen , Germany
10. CeGAT GmbH and Praxis für Humangenetik Tübingen , 72076 Tübingen , Germany
11. Department of Neurology, Martin-Luther-University Halle-Wittenberg , 06120 Halle (Saale) , Germany
12. Division for Neurodegenerative Diseases, Department of Neurology, Medical Faculty Mannheim, University of Heidelberg , 68167 Mannheim , Germany
13. Department of Child Neurology, Justus Liebig University , 35392 Giessen , Germany