Atypical presentations of spinal muscular atrophy type III (Kugelberg-Welander disease)

P. B. Kang, K. S. Krishnamoorthy, R. M. Jones, F. D. Shapiro, B. T. Darras

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11 Scopus citations


Spinal muscular atrophy type III (SMA III, Kugelberg-Welander disease) typically presents with symmetric proximal weakness, areflexia, and hypotonia. We present four children with spinal muscular atrophy type III who had atypical phenotypes. Three patients clearly had asymmetric weakness at presentation and two had upper motor neuron signs in the lower extremities (one patient had both features). Two of the patients had prolonged evaluations before the diagnosis was made. All patients had Gowers signs and two had pes planus. In patients with proximal muscle weakness the presence of asymmetrical weakness, upper motor neuron signs, or both, may be compatible with spinal muscular atrophy type III. The diagnosis of spinal muscular atrophy should be considered when other possibilities have been excluded.

Original languageEnglish (US)
Pages (from-to)492-494
Number of pages3
JournalNeuromuscular Disorders
Issue number8
StatePublished - Aug 2006
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the Spinal Muscular Atrophy Foundation (B.T.D., P.B.K.) and the Ellen Pappas Fund for Neuromuscular Research (B.T.D.).


  • Anterior horn cell
  • Electromyography
  • Kugelberg-Welander disease
  • Spinal muscular atrophy
  • Survival motor neuron


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