Degenerative Encephalopathy in Nova Scotia Duck Tolling Retrievers Presenting with a Rapid Eye Movement Sleep Behavior Disorder

Abstract

BackgroundNeurodegenerative diseases are a heterogeneous group of disorders characterized by loss of neurons and are commonly associated with a genetic mutation.Hypothesis/ObjectivesTo characterize the clinical and histopathological features of a novel degenerative neurological disease affecting the brain of young adult Nova Scotia Duck Tolling Retrievers (NSDTRs).AnimalsNine, young adult, related NSDTRs were evaluated for neurological dysfunction and rapid eye movement sleep behavior disorder.MethodsCase series review.ResultsClinical signs of neurological dysfunction began between 2 months and 5 years of age and were progressive in nature. They were characterized by episodes of marked movements during sleep, increased anxiety, noise phobia, and gait abnormalities. Magnetic resonance imaging documented symmetrical, progressively increasing, T2‐weighted image intensity, predominantly within the caudate nuclei, consistent with necrosis secondary to gray matter degeneration. Abnormalities were not detected on clinicopathological analysis of blood and cerebrospinal fluid, infectious disease screening or urine metabolite screening in most cases. Postmortem examination of brain tissue identified symmetrical malacia of the caudate nuclei and axonal dystrophy within the brainstem and spinal cord. Genealogical analysis supports an autosomal recessive mode of inheritance.Conclusions and Clinical ImportanceA degenerative encephalopathy was identified in young adult NSDTRs consistent with a hereditary disease. The prognosis is guarded due to the progressive nature of the disease, which is minimally responsive to empirical treatment.

Electroencephalography of rapid eye movement sleep behavior disorder in a dog with generalized tetanus

“…As with all but a single previously reported tetanus‐associated case, 9‐12 our dog had a generalized disease presentation, and resolution of RBD was seen with resolution of the underlying tetanus‐associated spasticity with no specific treatment. This outcome further supports the absence of additional underlying causes of RBD, because RBD in dogs with documented or suspected CNS disease frequently persisted or progressed with variable improvement with medical treatment 5‐8 …”

“…Sleep‐associated abnormal movements are reported uncommonly in the veterinary literature, but REM‐ and NREM‐associated conditions have been described. Idiopathic RBD, defined by electroencephalogram (EEG), has been reported in a Labrador puppy 5 and RBD was suspected in Nova Scotia Duck Tolling Retrievers with a degenerative encephalopathy 6 . A variety of REM and non‐REM movement disorders with both idiopathic and central nervous system (CNS) lesion‐related disorders were reported in 5 cats and 3 dogs based on observational and EEG documentation, 7 and suspected RBD in 13 dogs and EEG‐defined RBD in 1 dog were reported with minimally defined etiologies 8 …”

SLC25A12 Missense Variant in Nova Scotia Duck Tolling Retrievers Affected by Cerebellar Degeneration—Myositis Complex (CDMC)

“…Many of these inherited neurologic diseases are restricted to one of approximately 300 recognized dog breeds. In the Nova Scotia Duck Tolling Retriever (NSDTR) breed, a degenerative encephalopathy with presumed autosomal recessive inheritance has previously been described (OMIA 002055-9615) [ 2 ]. Affected dogs show episodes of marked movements during sleep, increased anxiety, noise phobia, and gait abnormalities.…”

“…Affected dogs show episodes of marked movements during sleep, increased anxiety, noise phobia, and gait abnormalities. MRI and post mortem examination showed symmetrical changes in the cerebellar caudate nuclei of affected dogs [ 2 ]. The causal genetic variant for the described disease has not been reported so far.…”

“…The current investigation was initiated after the presentation of an NSDTR litter, in which a single puppy showed a combination of cerebellar and neuromuscular signs that were not consistent with the previously published degenerative encephalopathy in the NSDTR [ 2 ]. Hence, a new inherited disease was suspected.…”