Pigment retinopathy in warmblood horses with equine degenerative myeloencephalopathy and equine motor neuron disease.
Abstract: 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. Unassigned: 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.
© 2016 American College of Veterinary Ophthalmologists.
Publication Date: 2016-08-05 PubMed ID: 27491953PubMed Central: PMC5292316DOI: 10.1111/vop.12417Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Ataxia
- Clinical Examination
- Clinical Findings
- Clinical Pathology
- Clinical Signs
- Clinical Study
- Disease Diagnosis
- Disease Etiology
- Disease Management
- Disease Outbreaks
- Disease Prevention
- Disease Surveillance
- Disease Treatment
- Equine Diseases
- Equine Motor Neuron Disease
- Genetics
- Horse Breeds
- Horses
- Neurological Diseases
- Neurology
- Ophthalmology
- Pathophysiology
- Post Mortem
- Retina
- Veterinary Care
- Veterinary Medicine
- Veterinary Research
- Vitamin E
- Warmblood Horses
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research is mainly focused on the occurrence of a pigment retinopathy in horses with equine motor neuron disease (EMND) and neuroaxonal dystrophy/equine degenerative myeloencephalopathy (NAD/EDM), which are conditions both linked to α-tocopherol (α-TP) deficiency. This is particularly relevant for Warmblood breed horses that have genetically predisposed susceptibilities.
Objective of the Research
The main aim of this study was to describe a pigment retinopathy, a condition not previously identified in horses with α-TP deficiency and subsequent NAD/EDM or EMND. This observation is primarily noted in a family of Warmblood horses. The research endeavored to bring to light new findings in the field of veterinary neuroscience and opthalmic health.
The Process
- Twenty-five Warmblood horses from a single farm were selected for the study.
- These horses underwent complete neurologic, as well as ophthalmic examinations. Serum α-TP concentrations in these horses were also evaluated.
- Two of the horses exhibiting the most significant ataxic symptoms were euthanized and postmortem examinations were conducted.
Findings
- The research found a prevalent α-TP deficiency among the horses in the tested farm with this showing up in 22 out of 25 horses.
- Out of the 25 horses, 11 horses did not display any clinical abnormalities, one showed signs of EMND, while 10 exhibited signs of ataxia, a condition related to NAD/EDM.
- It was established that two horses had both NAD/EDM and EMND, a finding that was post-mortem confirmed.
- Fundamentally, the research uncovered a pigment retinopathy in 5 horses. This was detected through the appearance of granular dark pigment in the tapetal retina of the horses’ eyes, which were either clinical manifestations of NAD/EDM. One horse surprisingly exhibited this as a sign of EMND.
Conclusion
The research concludes that a pigment retinopathy can be a symptom in young horses that display clinical signs of both EMND and NAD/EDM, and are deficient in α-TP. This emerging evidence is significantly relevant for the Warmblood breed, and warrants further investigation.
Cite This Article
APA
Finno CJ, Kaese HJ, Miller AD, Gianino G, Divers T, Valberg SJ.
(2016).
Pigment retinopathy in warmblood horses with equine degenerative myeloencephalopathy and equine motor neuron disease.
Vet Ophthalmol, 20(4), 304-309.
https://doi.org/10.1111/vop.12417 Publication
Researcher Affiliations
- Population Health and Reproduction, School of Veterinary Medicine, School of Medicine, University of California, Davis, CA, 95616, USA.
- Eye Care for Animals, Lees Summit, MO, 64064, USA.
- Section of Anatomic Pathology, Department of Biomedical Sciences Medicine, Cornell University College of Veterinary, Ithaca, NY, 14853, USA.
- Population Health and Reproduction, School of Veterinary Medicine, School of Medicine, University of California, Davis, CA, 95616, USA.
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, 14853, USA.
- Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, 48895, USA.
MeSH Terms
- Animals
- Brain Diseases / diagnosis
- Brain Diseases / veterinary
- Female
- Horse Diseases / diagnosis
- Horse Diseases / pathology
- Horses
- Male
- Motor Neuron Disease / diagnosis
- Motor Neuron Disease / pathology
- Motor Neuron Disease / veterinary
- Neurologic Examination / veterinary
- Pedigree
- Pigments, Biological
- Retinal Diseases / diagnosis
- Retinal Diseases / pathology
- Retinal Diseases / veterinary
- Vitamin E Deficiency / diagnosis
- Vitamin E Deficiency / pathology
- Vitamin E Deficiency / veterinary
- alpha-Tocopherol / blood
Grant Funding
- K01 OD015134 / NIH HHS
- L40 TR001136 / NCATS NIH HHS
References
This article includes 23 references
- Schneider C. Chemistry and biology of vitamin E. Molecular Nutrition & Food Research 2005;49:7–30.
- Finno CJ, Valberg SJ. A comparative review of vitamin E and associated equine disorders. Journal of Veterinary Internal Medicine 2012;26:1251–1266.
- Yokota T, Igarashi K, Uchihara T. Delayed-onset ataxia in mice lacking alpha-tocopherol transfer protein: model for neuronal degeneration caused by chronic oxidative stress. Proceedings of the National Academy of Sciences of the United States of America 2001;98:15185–15190.
- Hayes KC. Pathophysiology of vitamin E deficiency in monkeys. The American Journal of Clinical Nutrition 1974;27:1130–1140.
- Riis RC, Sheffy BE, Loew E. Vitamin E deficiency retinopathy in dogs. American Journal of Veterinary Research 1981;42:74–86.
- McLellan GJ, Cappello R, Mayhew IG. Clinical and pathological observations in English cocker spaniels with primary metabolic vitamin E deficiency and retinal pigment epithelial dystrophy. The Veterinary Record 2003;153:287–292.
- Davidson MG, Geoly FJ, Gilger BC. Retinal degeneration associated with vitamin E deficiency in hunting dogs. Journal of the American Veterinary Medical Association 1998;213:645–651.
- Yokota T, Shiojiri T, Gotoda T. Retinitis pigmentosa and ataxia caused by a mutation in the gene for the alpha-tocopherol-transfer protein. The New England Journal of Medicine 1996;335:1770–1771.
- Riis RC, Jackson C, Rebhun W. Ocular manifestations of equine motor neuron disease. Equine Veterinary Journal 1999;31:99–110.
- Muller DP. Vitamin E and neurological function. Molecular Nutrition & Food Research 2010;54:710–718.
- Aleman M, Finno CJ, Higgins RJ. Evaluation of epidemiological, clinical, and pathological features of neuroaxonal dystrophy in Quarter Horses. Journal of the American Veterinary Medical Association 2011;239:823–833.
- Finno CJ, Higgins RJ, Aleman M. Equine degenerative myeloencephalopathy in Lusitano horses. Journal of Veterinary Internal Medicine 2011;25:1439–1446.
- Finno CJ, Estell K, Katzman S. Blood and cerebrospinal fluid alpha-tocopherol and selenium concentrations in neonatal foals with neuroaxonal dystrophy. Journal of Veterinary Internal Medicine 2015;29:1667–1675.
- Mohammed HO, Divers TJ, Summers BA. Vitamin E deficiency and risk of equine motor neuron disease. Acta Veterinaria Scandinavica 2007;49:17.
- Finno CJ, Aleman M, Ofri R. Electrophysiological studies in American Quarter horses with neuroaxonal dystrophy. Veterinary Ophthalmology 2012;15(Suppl 2):3–7.
- Garbe JR, Da Y. Pedigraph: A Software Tool for the Graphing and Analysis of Large Complex Pedigrees. User Manual Version 2.4. .
- Divers TJ, De Lahunta A, Hintz HF. Equine motor neuron disease. Equine Veterinary Education 2001;13:63–67.
- Finno CJ, Famula T, Aleman M. Pedigree analysis and exclusion of alpha-tocopherol transfer protein (TTPA) as a candidate gene for neuroaxonal dystrophy in the American Quarter Horse. Journal of Veterinary Internal Medicine 2013;27:177–185.
- Finno CJ, Aleman M, Higgins RJ. Risk of false positive genetic associations in complex traits with underlying population structure: a case study. Veterinary Journal 2014;202:543–549.
- Cummings JF, de Lahunta A, George C. Equine motor neuron disease; a preliminary report. The Cornell Veterinarian 1990;80:357–379.
- Stone WL, Farnsworth CC, Dratz EA. A reinvestigation of the fatty acid content of bovine, rat and frog retinal rod outer segments. Experimental Eye Research 1979;28:387–397.
- Finno CJ, Miller AD, Siso S. Concurrent equine degenerative myeloencephalopathy and equine motor neuron disease in three young horses. Journal of Veterinary Internal Medicine 2016;30:1344–50. In Press.
- Bedford HE, Valberg SJ, Firshman AM. Histopathologic findings in the sacrocaudalis dorsalis medialis muscle of horses with vitamin E-responsive muscle atrophy and weakness. Journal of the American Veterinary Medical Association 2013;242:1127–1137.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
