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 ?-tocopherol (?-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 ?-TP deficiency. The objective of this report is to describe, for the first time, a pigment retinopathy in a family of ?-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 ?-TP concentrations were assessed. Two of the most severely ataxic horses were euthanized and postmortem examinations performed.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.A pigment retinopathy can be present in young ?-TP-deficient Warmblood horses with clinical signs of EMND as well as those with signs of NAD/EDM.

SUBMITTER: Finno CJ 

PROVIDER: S-EPMC5292316 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature