[1] Columbia Univ Coll Phys & Surg, Dept Neurol, H Houston Merritt Clin Res Ctr Muscular Dystrophy, New York, NY 10032 USA
[2] Hosp Gen Valle Hebron, Ctr Invest Bioquim & Biol Mol, Barcelona, Spain
[3] Sapporo City Gen Hosp, Dept Neurol, Sapporo, Hokkaido, Japan