title: The natural history of severe spinal muscular atrophy--further evidence for clinical subtypes.
authors.forename: J
authors.initials: J
authors.lastname: Ignatius
mesh_terms: D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D014897:Spinal Muscular Atrophies of Childhood / Q000503:physiopathology*