Folkhälsan Research Center (M. Savarese, A.V., M.J., P.H.J., P.H., B.U.), Helsinki; Department of Medical Genetics (M. Savarese, A.V., M.J., P.H.J., P.H., B.U.), Medicum, University of Helsinki; Neuromuscular Research Center (A.V.), Department of Genetics, Fimlab Laboratories, Tampere; Division of Clinical Neurosciences (M.E.J.), Department of Neurology, Turku University and University Hospital; Neuromuscular Research Center (S.P.H.), Department of Pathology, Fimlab Laboratories, Tampere, Finland; Neuroradiology Unit (S.G.), ASST Papa Giovanni XXIII, Bergamo; Dipartimento di Medicina di Precisione (A.T., M.E.O., V.N.), Università degli Studi della Campania "Luigi Vanvitelli," Napoli; Telethon Institute of Genetics and Medicine (A.T., V.N.), Pozzuoli; Division of Neuroscience and U.O. Neurologia (M. Scarlato, S.C.P.), IRCCS Ospedale San Raffaele, Milano, Italy; Randall Centre for Cell and Molecular Biophysics (M.G.), King's College London BHF Centre of Research Excellence, United Kingdom; Department of Neurology (B.U.), Vaasa Central Hospital; and Neuromuscular Research Center (M.E.J., B.U.), Department of Neurology, Tampere University and University Hospital, Finland.