1. Department of Human Genetics, Leiden University Medical Centre, Leiden
2. Department of Neurology, Leiden University Medical Centre, Leiden
3. Department of Paediatrics, Division of Neonatology and Paediatric Intensive Care, University of Greifswald, Greifswald, Germany
4. Centre for Human and Clinical Genetics, Leiden University Medical Centre, Leiden
5. Department of Paediatrics, Division of Neuropaediatrics and Metabolic Diseases, University of Greifswald, Greifswald, Germany
6. Department of Neurology, Rijnland Hospital, Leiderdorp, the Netherlands