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Differentiating lower motor neuron syndromes
  1. Nidhi Garg1,
  2. Susanna B Park1,
  3. Steve Vucic2,
  4. Con Yiannikas3,
  5. Judy Spies1,
  6. James Howells1,
  7. William Huynh1,4,
  8. José M Matamala1,
  9. Arun V Krishnan4,
  10. John D Pollard1,
  11. David R Cornblath5,
  12. Mary M Reilly6,
  13. Matthew C Kiernan1
  1. 1Brain and Mind Centre, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
  2. 2Departments of Neurology and Neurophysiology, Westmead Hospital, The University of Sydney, Sydney, New South Wales, Australia
  3. 3Department of Neurology, Concord and Royal North Shore Hospitals, The University of Sydney, Sydney, New South Wales, Australia
  4. 4Prince of Wales Clinical School, The University of New South Wales, Sydney, New South Wales, Australia
  5. 5Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
  6. 6MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, London, UK
  1. Correspondence to Professor Matthew C Kiernan, Brain and Mind Centre, The University of Sydney, 94 Mallett Street Camperdown, Sydney, NSW 2050, Australia; matthew.kiernan{at}


Lower motor neuron (LMN) syndromes typically present with muscle wasting and weakness and may arise from pathology affecting the distal motor nerve up to the level of the anterior horn cell. A variety of hereditary causes are recognised, including spinal muscular atrophy, distal hereditary motor neuropathy and LMN variants of familial motor neuron disease. Recent genetic advances have resulted in the identification of a variety of disease-causing mutations. Immune-mediated disorders, including multifocal motor neuropathy and variants of chronic inflammatory demyelinating polyneuropathy, account for a proportion of LMN presentations and are important to recognise, as effective treatments are available. The present review will outline the spectrum of LMN syndromes that may develop in adulthood and provide a framework for the clinician assessing a patient presenting with predominantly LMN features.


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  • Contributors MCK, SBP and NG conceived the idea for the article. NG drafted the manuscript. All authors revised the manuscript critically for important intellectual content, and gave final approval of the version to be published.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Commissioned; externally peer reviewed.

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