[1] Inst Politecn Nacl, Escuela Super Med, Secc Posgrad, Mexico City 11340, DF, Mexico
[2] ISSSTE, Ctr Med Nacl Noviembre 20, Subdirecc Ensenanza & Invest, Div Invest Biomed, Mexico City, DF, Mexico
[3] Secretaria Salud Mexico, Inst Nacl Rehabil, Dept Morfol Celular & Mol, Mexico City, DF, Mexico
[4] Hosp Pediat Mexico City, Ctr Med Nacl Siglo XXI IMSS, Unidad Invest Med Genet Humana, Mexico City, DF, Mexico
[5] Hosp Gen Durango, Durango, Mexico
[6] Inst Nacl Neurol & Neurocirugia Manuel Velasco Su, Dept Patol Expt, Mexico City, DF, Mexico
[7] Secretaria Salud Mexico, Inst Nacl Rehabil, Serv Electrodiagnost, Mexico City, DF, Mexico
[8] Secretaria Salud Mexico, Inst Nacl Rehabil, Lab Bioquim Muscular, Mexico City, DF, Mexico