Clinical Characterization of a Familial Degenerative Myelopathy in Pembroke Welsh Corgi Dogs

Abstract

Background: Adult dogs with degenerative myelopathy (DM) have progressive ataxia and paresis of the pelvic limbs, leading to paraplegia and euthanasia. Although most commonly reported in German Shepherd dogs, high disease prevalence exists in other breeds.Objective: Our aim was the clinical and histopathologic characterization of familial degenerative myelopathy (FDM) in Pembroke Welsh Corgi (PWC) dogs.Animals: Twenty-one PWCs were prospectively studied from initial diagnosis until euthanasia. Methods: Neurologic examination, blood tests, cerebrospinal fluid (CSF) analysis, electrodiagnostic testing, and spinal imaging were performed. Concentrations of 8-iso-prostaglandin F 2 a (8-isoprostane) were measured in CSF. Routine histochemistry was used for neuropathology. Deoxyribonucleic acid and pedigrees were collected from 110 dogs.Results: Median duration of clinical signs before euthanasia was 19 months. Median age at euthanasia was 13 years. All dogs were nonambulatory paraparetic or paraplegic, and 15 dogs had thoracic limb weakness at euthanasia. Electrodiagnostic testing and spinal imaging were consistent with noncompressive myelopathy. No significant difference was detected in 8-isoprostane concentrations between normal and FDM-affected dogs. Axonal and myelin degeneration of the spinal cord was most severe in the dorsal portion of the lateral funiculus. Pedigree analysis suggested a familial disease.Conclusions and Clinical Importance: Clinical progression of FDM in PWC dogs was similar to that observed in other breeds but characterized by a longer duration. Spinal cord pathology predominates as noninflammatory axonal degeneration. Oxidative stress injury associated with 8-isoprostane production is not involved in the pathogenesis of FDM-affected PWC dogs. A familial disease is suspected.

Genome-wide association analysis reveals a SOD1 mutation in canine degenerative myelopathy that resembles amyotrophic lateral sclerosis

“…Since these early reports, DM has been diagnosed in several other breeds. The disease is common in certain breeds including the Pembroke Welsh corgi, Boxer, Rhodesian ridgeback, and Chesapeake Bay retriever (14).…”

“…Most dogs are at least 8 years old before the onset of clinical signs (11)(12)(13)(14)(15)(16)(17)(18). The initial clinical sign is a spastic and general proprioceptive ataxia in the pelvic limbs.…”

“…At this stage of the disease, the presence of spinal reflexes indicates an upper motor neuron paresis (11). The asymmetric weakness frequently reported at disease onset progresses to paraplegia (11,12,14,16,18). Hyporeflexia of the myotatic and withdrawal reflexes occur in the latter disease stage (11,12,14,16,18).…”

“…The asymmetric weakness frequently reported at disease onset progresses to paraplegia (11,12,14,16,18). Hyporeflexia of the myotatic and withdrawal reflexes occur in the latter disease stage (11,12,14,16,18). The disease duration can exceed 3 years; however, dog owners usually elect euthanasia within a year of diagnosis when their dogs become paraplegic.…”

“…The disease duration can exceed 3 years; however, dog owners usually elect euthanasia within a year of diagnosis when their dogs become paraplegic. If the disease is allowed to progress, clinical signs will ascend to affect the thoracic limbs (11,14,16). Because various common acquired compressive spinal cord diseases can mimic DM by compromising the upper motor neuron and general proprioceptive pathways, a definitive diagnosis of DM can only be accomplished postmortem by the histopathologic observation of axonal and myelin degeneration, which can occur at all levels of the spinal cord (16)(17)(18) and in all spinal cord funiculi, but are consistently most severe in the dorsal portion of the lateral funiculus within the middle to caudal thoracic region (11,(13)(14)(15)(16)(17)(18).…”