title: Peripheral neuropathy in hereditary spastic paraplegia due to spastin (SPG4) mutation--a neurophysiological study using excitability techniques.
abstract: OBJECTIVE
  To identify peripheral nerve abnormalities in hereditary spastic paraplegia (HSP) due to mutations in the spastin gene (spastic paraplegia 4, SPG4) using standard nerve conduction (NCS) and novel tests of axonal excitability.
  
  
  METHODS
  Eleven patients with known mutations in spastin were assessed with NCS for the upper and lower limbs, and axonal excitability testing on the median nerve.
  
  
  RESULTS
  Standard nerve conduction studies revealed a sensorimotor neuropathy in two patients. Excitability studies on median motor axons showed an isolated abnormality (increased strength-duration time constant), but those on sensory axons were normal in nine patients with normal routine nerve conduction studies.
  
  
  CONCLUSIONS
  Peripheral neuropathy occurs in HSP patients with SPG4 mutations, but axonal excitability studies provide limited additional evidence for subclinical peripheral nerve dysfunction, and add little further to standard nerve conduction studies.
  
  
  CONCLUSIONS
  The features of HSP due to SPG4 mutations include sensorimotor polyneuropathy. The value of excitability studies is limited in individual patients.
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Royal North Shore Hospital, St Leonards, NSW 2065, Australia.
authors.forename: Kishore R
authors.initials: KR
authors.lastname: Kumar
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Sue
authors.forename: David
authors.initials: D
authors.lastname: Burke
authors.forename: Karl
authors.initials: K
authors.lastname: Ng
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics*; D000328:Adult; D000368:Aged; D001369:Axons / Q000502:physiology; D004558:Electric Stimulation; D004568:Electrodiagnosis; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D009154:Mutation / Q000235:genetics*; D009431:Neural Conduction / Q000502:physiology; D009482:Neurophysiology / Q000379:methods*; D010523:Peripheral Nervous System Diseases / Q000235:genetics* / Q000503:physiopathology; D015419:Spastic Paraplegia, Hereditary / Q000235:genetics* / Q000503:physiopathology; D000074181:Spastin
chemical_list: D000251:Adenosine Triphosphatases; D000074181:Spastin; C400283:SPAST protein, human