1. Child Neurology Department, Medical University of Silesia, Katowice, Poland
2. Department of Neuropathology, Institute of Neurology, Medical College, Jagiellonian University, Krakow, Poland
3. Child Neurology Department, Medical University of Silesia, Katowice, Poland,
4. Laboratory Diagnostics Department, The Children's Memorial Health Institute, Warsaw, Poland
5. Laboratory of Pediatrics and Neurology, Randboud University Nijmegen Medical Centre, Nijmegen, Netherlands