The motor neuron response to SMN1 deficiency in spinal muscular atrophy. Issue 5 (May 2014)

• Record Type: Journal Article
• Authors: Kang, Peter B.; Gooch, Clifton L.; McDermott, Michael P.; Darras, Basil T.; Finkel, Richard S.; Yang, Michele L.; Sproule, Douglas M.; Chung, Wendy K.; Kaufmann, Petra; de, Darryl C.
• Is Part Of: Muscle & nerve. Volume 49:Issue 5(2014:May)
• Page Start: 636
• Page End: 644
• Publication Date: 2014-05
• Subjects: Neuromuscular diseases -- Periodicals; Muscles -- Periodicals; Nerves -- Periodicals; 616.74
• DOI: 10.1002/mus.23967
• Languages: English
• ISSNs: 0148-639X

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p> <italic>Introduction</italic>: The purpose of this study was to measure and analyze motor unit number estimation (MUNE) values longitudinally in spinal muscular atrophy (SMA). <italic>Methods</italic>: Sixty‐two children with SMA types 2 and 3 were observed prospectively for up to 42 months. Longitudinal electrophysiological data were collected, including compound motor action potential (CMAP), single motor unit action potential (SMUP), and MUNE. <italic>Results</italic>: Significant motor neuron loss and compensatory collateral reinnervation were noted at baseline. Over time, there was a significant mean increase in MUNE (4.92 units/year, <italic>P</italic> = 0.009), a mean decrease in SMUP amplitude (−6.32 μV/year, <italic>P</italic> = 0.10), and stable CMAP amplitude. <italic>Conclusions</italic>: The unexpected longitudinal results differ from findings in amyotrophic lateral sclerosis studies, perhaps indicating that compensatory processes in SMA involve new motor unit development. A better understanding of the mechanisms of motor unit decline and compensation in SMA is important for assessing novel therapeutic strategies and for providing key insights into disease pathophysiology. <italic>Muscle Nerve</italic><bold>49</bold>: 636–644, 2014</p> </abstract>