[1] Ist Nazl Neurol Carlo Besta, Div Biochem & Genet, Milan, Italy
[2] Ist Nazl Neurol Carlo Besta, Epidemiol Unit, Milan, Italy
[3] Univ Dept Neurol Ophthalmol & Genet, Genoa, Italy
[4] Univ Neurol Clin, Catanzaro, Italy
[5] Univ Dept Neurol & Visual Sci, Sect Clin Neurol, Verona, Italy
[6] Univ Naples Federico II, Dept Neurol Sci, Naples, Italy
[7] Univ Neurol Clin, Messina, Italy
[8] Univ Neurol Clin, Parma, Italy
[9] Catholic Univ, Dept Neurosci, Rome, Italy