1. Department of Paediatrics and Child Health, Kilimanjaro Christian Medical Centre, P.O. Box 3010, Moshi, Tanzania
2. Department of Human Genetics, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, Netherlands
3. Department of Neurology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, Netherlands