title: Spinal muscular atrophy type III: trying to understand subtle functional change over time--a case report.
abstract: Spinal muscular atrophy is a relatively stable chronic disease. Patients may gradually experience declines in muscle strength and motor function over time. However, functional progression is difficult to document, and the mechanism remains poorly understood. An 11-year-old girl was diagnosed at 19 months and took a few steps without assistance at 25 months. She was evaluated for 54 months in a prospective multicenter natural history study. Outcome measures were performed serially. From 6 to 7.5 years, motor function improved. From 7.5 to 11 years, motor function declined with increasing growth. Manual muscle testing scores minimally decreased. Motor unit number estimation studies gradually increased over 4.5 years. Compared to the published natural history of spinal muscular atrophy type III, our patient lost motor function over time. However, she walked with assistance 2 years longer than expected. Our report highlights possible precipitating factors that could affect the natural history of spinal muscular atrophy type III.
authors.affiliation: SMA Clinical Research Center, Columbia University Medical Center, New York, NY 10032, USA. sld2120@columbia.edu
authors.forename: Sally
authors.initials: S
authors.lastname: Dunaway
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Montes
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Ryan
authors.forename: Megan
authors.initials: M
authors.lastname: Montgomery
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Sproule
authors.forename: Darryl C
authors.initials: DC
authors.lastname: De Vivo
mesh_terms: D000927:Anticonvulsants / Q000627:therapeutic use; D002648:Child; D018479:Early Intervention, Educational; D045853:Exhalation / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D009043:Motor Activity / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D017063:Outcome Assessment, Health Care; D020127:Recovery of Function / Q000502:physiology*; D014897:Spinal Muscular Atrophies of Childhood / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D014635:Valproic Acid / Q000627:therapeutic use; D016138:Walking / Q000502:physiology
chemical_list: D000927:Anticonvulsants; D014635:Valproic Acid