title: Equine degenerative myeloencephalopathy in Lusitano horses.
abstract: BACKGROUND
  Equine degenerative myeloencephalopathy (EDM) is a neurodegenerative disorder that has been previously associated with low vitamin E concentrations.
  
  
  OBJECTIVE
  To describe the clinical, electrophysiologic, and pathologic features of EDM in a group of related Lusitano horses.
  
  
  METHODS
  Fifteen Lusitano horses.
  
  
  METHODS
  Neurologic examinations were conducted, and serum vitamin E concentrations were measured. Three neurologically abnormal horses were further evaluated by ophthalmologic examination, electroretinography, electroencephalography, muscle and nerve biopsies, and post-mortem examination.
  
  
  RESULTS
  Six horses appeared neurologically normal, 6 were neurologically abnormal, and 3 had equivocal gait abnormalities. Abnormal horses demonstrated ataxia and paresis. An inconsistent menace response was noted in 4 neurologically abnormal horses and in 1 horse with equivocal findings. All horses had low serum vitamin E concentrations (<1.5 ppm). Ophthalmologic examinations, electroretinograms, electroencephalograms, and muscle and peripheral nerve biopsies were unremarkable in 3 neurologically abnormal horses. At necropsy, major neuropathological findings in these horses were bilaterally symmetric, severe, neuro axonal degeneration in the gracilis, cuneatus medialis, cuneatus lateralis, and thoracicus nuclei and bilaterally symmetric axonal loss and demyelination mainly in the dorsolateral and ventromedial tracts of the spinal cord. A diagnosis of EDM was made based on these findings. Pedigree analysis identified 2 sires among the affected horses.
  
  
  CONCLUSIONS
  Equine degenerative myeloencephalopathy is a neurodegenerative disorder that causes ataxia and, in severe cases, paresis, in young Lusitano horses. The disease appears to have a genetic basis, and although vitamin E deficiency is a common finding, low serum vitamin E concentrations also may occur in apparently unaffected related individuals.
authors.affiliation: William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California Davis, CA 95616, USA. cjfinno@ucdavis.edu
authors.forename: C J
authors.initials: CJ
authors.lastname: Finno
authors.forename: R J
authors.initials: RJ
authors.lastname: Higgins
authors.forename: M
authors.initials: M
authors.lastname: Aleman
authors.forename: R
authors.initials: R
authors.lastname: Ofri
authors.forename: S R
authors.initials: SR
authors.lastname: Hollingsworth
authors.forename: D L
authors.initials: DL
authors.lastname: Bannasch
authors.forename: C M
authors.initials: CM
authors.lastname: Reilly
authors.forename: J E
authors.initials: JE
authors.lastname: Madigan
mesh_terms: D000818:Animals; D004679:Encephalomyelitis / Q000209:etiology / Q000235:genetics / Q000473:pathology / Q000662:veterinary*; D005260:Female; D020022:Genetic Predisposition to Disease; D006734:Horse Diseases / Q000209:etiology / Q000235:genetics / Q000473:pathology*; D006736:Horses; D008297:Male; D010375:Pedigree; D014811:Vitamin E Deficiency / Q000150:complications / Q000662:veterinary*