[1] Univ Ferrara, Dept Med Sci, Unit Med Genet, Ferrara, Italy
[2] IRCCS Osped San Raffaele, Neuromuscular Repair Unit, Head InSpe, Milan, Italy
[3] IRCCS Osped San Raffaele, Div Neurosci, Milan, Italy
[4] UCL Great Ormond St Inst Child Hlth, Dubowitz Neuromuscular Ctr, London, England