title: Pigment retinopathy in warmblood horses with equine degenerative myeloencephalopathy and equine motor neuron disease.
abstract: OBJECTIVE
  A pigment retinopathy has been reported in adult horses with equine motor neuron disease (EMND) arising from chronic α-tocopherol (α-TP) deficiency. A pigment retinopathy has not been identified in horses with neuroaxonal dystrophy/equine degenerative myeloencephalopathy (NAD/EDM) that affects genetically susceptible young horses with α-TP deficiency. The objective of this report is to describe, for the first time, a pigment retinopathy in a family of α-TP-deficient Warmbloods (WB) with clinically apparent NAD/EDM or EMND.
  Twenty-five WB horses from one farm underwent complete neurologic and ophthalmic examinations and serum α-TP concentrations were assessed. Two of the most severely ataxic horses were euthanized and postmortem examinations performed.
  
  
  RESULTS
  Alpha-TP deficiency was widespread on this farm (22 of 25 horses). Eleven of 25 horses were clinically normal (age range 2-12 years), one had signs of EMND (6 years of age), 10 had signs of ataxia consistent with NAD/EDM (1-10 years), and two of these were postmortem confirmed concurrent NAD/EDM and EMND. A pigment retinopathy characterized by varying amounts of granular dark pigment in the tapetal retina was observed in four clinically apparent NAD/EDM horses (two postmortem confirmed concurrent NAD/EDM and EMND) and one horse with clinical signs of EMND.
  
  
  CONCLUSIONS
  A pigment retinopathy can be present in young α-TP-deficient Warmblood horses with clinical signs of EMND as well as those with signs of NAD/EDM.
authors: Population Health and Reproduction, School of Veterinary Medicine, School of Medicine, University of California, Davis, CA, 95616, USA.
authors: Carrie J
authors: CJ
authors: Finno
authors: Eye Care for Animals, Lees Summit, MO, 64064, USA.
authors: Heather J
authors: HJ
authors: Kaese
authors: Section of Anatomic Pathology, Department of Biomedical Sciences Medicine, Cornell University College of Veterinary, Ithaca, NY, 14853, USA.
authors: Andrew D
authors: AD
authors: Miller
authors: Population Health and Reproduction, School of Veterinary Medicine, School of Medicine, University of California, Davis, CA, 95616, USA.
authors: Giuliana
authors: G
authors: Gianino
authors: Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, 14853, USA.
authors: Thomas
authors: T
authors: Divers
authors: Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, 48895, USA.
authors: Stephanie J
authors: SJ
authors: Valberg
mesh_terms: D000818:Animals; D001927:Brain Diseases / Q000175:diagnosis / Q000662:veterinary*; D005260:Female; D006734:Horse Diseases / Q000175:diagnosis* / Q000473:pathology; D006736:Horses; D008297:Male; D016472:Motor Neuron Disease / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D009460:Neurologic Examination / Q000662:veterinary; D010375:Pedigree; D010860:Pigments, Biological; D012164:Retinal Diseases / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D014811:Vitamin E Deficiency / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D024502:alpha-Tocopherol / Q000097:blood
chemical_list: D010860:Pigments, Biological; D024502:alpha-Tocopherol
keywords: horse; lipofuscin; neurodegeneration; retina; tocopherol; vitamin E