1. From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I....