Objective—To characterize lysosomal storage body
accumulation in the retina and brain of Tibetan Terriers
with ceroid-lipofuscinosis and determine whether the
disease in these dogs is accompanied by impaired
retinal function and retinal degeneration.
Animals—Three 7- to 10-year-old Tibetan Terriers with
ceroid-lipofuscinosis and 1 healthy 5-year-old Tibetan
Procedure—Owners completed a questionnaire to
identify behavioral and physical signs indicative of
ceroid-lipofuscinosis. Neurologic, behavioral, and
ophthalmologic evaluations, including full-field electroretinograms,
were performed on each dog.
Fluorescence, light, and electron microscopy were
performed on specimens of retina, cerebral cortex,
and cerebellum of all dogs postmortem.
Results—Behavioral assessments of the affected
dogs revealed moderate visual impairment in lowlight
conditions but good vision in bright light. On
funduscopic evaluation of these dogs, abnormalities
detected ranged from none to signs of moderately
advanced retinal degeneration. Compared with findings
in the control dog, electroretinography revealed
depressed rod cell function with some impairment
of cone cell function in the affected dogs.
Morphologically, disease-specific storage bodies
were detected in retinal Müller cells and neurons,
particularly in ganglion cells, and in cells of the cerebral
cortex and cerebellum in affected dogs.
Substantial photoreceptor cell loss and disruption of
photoreceptor outer segment morphology appeared
to develop late in the disease.
Conclusions and Clinical Relevance—The similarities
between ceroid-lipofuscinosis in Tibetan Terriers and
some forms of ceroid-lipofuscinosis in humans suggest
that the canine disease may have a genetic and
biochemical basis similar to that of one of the ceroidlipofuscinosis
disorders in humans. (Am J Vet Res 2005;66:67–76)