1 Department of Pediatrics, Haukeland University Hospital, 5021, Bergen, Norway.
2 Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway.
3 Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway.
4 Department of Paediatric and Adolescent Medicine, University Hospital of North Norway, Tromsø, Norway.
5 Paediatric Research Group, Department of Clinical Medicine, UiT- The Arctic University of Norway, Tromsø, Norway.
6 Women and Children's Division, Department of Clinical Neurosciences for Children, Oslo University Hospital, Oslo, Norway.
7 Unit for Congenital and Hereditary Neuromuscular Disorders, Department of Neurology, Oslo University Hospital, Oslo, Norway.
8 Department of Neurology, Oslo University Hospital, Oslo, Norway.
9 Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
10 Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway.
11 Department of Neurology and Clinical Neurophysiology, St. Olav's University Hospital, Trondheim, Norway.
12 Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway.
13 Department of Clinical Science (K2), University of Bergen, Bergen, Norway.
14 Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School Framlington Place, Newcastle University, Newcastle upon Tyne, UK.
15 Mitochondrial Research Group, UCL Great Ormond Street Institute of Child Health, London, UK.
16 Metabolic Unit, Great Ormond Street Hospital NHS Foundation Trust, London, UK.
17 Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway. laurence.bindoff@nevro.uib.no.
18 Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway. laurence.bindoff@nevro.uib.no.