[1] Radboud Univ Nijmegen, Dept Neurol, Med Ctr, Donders Inst Brain Cognit & Behav, NL-6500 HB Nijmegen, Netherlands
[2] Imperial Coll Healthcare Natl Hlth Serv Trust, Dept Paediat Neurol, London, England
[3] Radboud Univ Nijmegen, Dept Lab Med, Med Ctr, NL-6500 HB Nijmegen, Netherlands
[4] Radboud Univ Nijmegen, Dept Genet, Med Ctr, NL-6500 HB Nijmegen, Netherlands
[5] Radboud Univ Nijmegen, Dept Paediat Neurol, Med Ctr, Donders Inst Brain Cognit & Behav, NL-6500 HB Nijmegen, Netherlands