[1] Univ Hosp RWTH Aachen, Inst Human Genet, Aachen, Germany
[2] Istanbul Univ, Istanbul Fac Med, Neuromuscular Unit, Dept Neurol, Istanbul, Turkey
[3] UCL Queen Sq Inst Neurol, Ctr Neuromuscular Dis, London, England
[4] Univ Zurich, Univ Hosp Zurich, Dept Clin Chem, Zurich, Switzerland
[5] Ludwig Maximilians Univ Munchen, Friedrich Baur Inst, Dept Neurol, Munich, Germany
[6] Med Univ Vienna, Dept Orthoped & Trauma Surg, Vienna, Austria
[7] Cambridge Inst Med Res, Keith Peters Bldg,Cambridge Biomed Campus, Cambridge, England
[8] Charles Univ Prague, Dept Paediat Neurol, Prague, Czech Republic
[9] Motol Univ Hosp, Prague, Czech Republic