1. From the University Children's Hospital Salzburg (S.B.W., R.G.F., J.A.M.), Austria; Amalia Children's Hospital (S.B.W., L.A.G., J. Hebbink, M.A.W.), Department of Pediatrics (Pediatric Neurology), Nijmegen, The Netherlands; Division of Child Neurology (L.A., E.B.), University Children's Hospital Zurich, Switzerland; Pediatric Neurology Department (M.A.), Necker-Enfants Malades University Hospital, Paris Cité University, APHP; Reference Centre for Mitochondrial Disorders (CARAMMEL) (C.-M.D.-B., M.S.)...