1. Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
2. Department of Biology and Genetics, Medical University, Gdańsk, Poland
3. Department of Pediatrics, Medical University, Gdańsk, Poland
4. Department of Pediatric Neurology, Silesian School of Medicine, Katowice, Poland
5. Max‐Planck‐Institute of Molecular Genetics, Berlin, Germany