1. Department of Paediatric Neurology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
2. Leeds Genetics Laboratory, St. James's University Hospital, Leeds, United Kingdom
3. Hull Royal Infirmary, Hull, United Kingdom
4. Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
5. Department of Clinical Genetics, Leeds, United Kingdom
6. Department of Child Neurology, VU University Medical Center, Amsterdam, The Netherlands
7. School of Medicine, University of Leeds, St. James's University Hospital, Leeds, United Kingdom