[1] Catholic Univ, Dept Paediat Neurol, Rome, Italy
[2] Univ Pavia, IRCCS C Mondino Fdn, Child Neurol & Psychiat Unit, I-27100 Pavia, Italy
[3] Univ Messina, Dept Neurosci Psychiat & Anaesthesiol, Messina, Italy
[4] Bambino Gesu Pediat Hosp, Dept Lab Med, Mol Med Unit, Rome, Italy
[5] Inst Child Hlth, Dubowitz Neuromuscular Unit, London, England
[6] G Gaslini Inst Children, Neuromuscular Dis Unit, Genoa, Italy
[7] Seconda Univ Napoli, Dipartimento Med Chirurg Internist Clin & Sperime, Naples, Italy
[8] Univ Pisa, Stella Maris Inst, Dept Dev Neurosci, I-56100 Pisa, Italy
[9] Univ Padua, Dept Neurosci, Padua, Italy
[10] Maggiore Hosp, Child Neurol & Psychiat Unit, Bologna, Italy
[11] Univ Turin, SG Battista Hosp, Neuromuscular Ctr, I-10124 Turin, Italy
[12] Catholic Univ, Dept Stat, Rome, Italy
[13] Meyer Hosp, Metab & Neuromuscular Unit, Florence, Italy