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Objective: To elucidate the nature of ataxia observed in 3 cats spanning 2 generations., Design: Experimental breeding was attempted to confirm heritability of the disease and establish the mode of inheritance; the original 3 cats and their offspring were studied., Animals: Seven diseased cats spanning 3 generations and 11 neurologically normal cats., Procedure: Cats were examined by use of the following methods: clinical observation, hematologic and serum biochemical examinations, neurologic examination, electrodiagnostics, magnetic resonance imaging, lysosomal enzyme activity assay, horizontal transmission test, and virologic and pathologic examinations., Results: All kittens (1 male and 3 females) obtained by backcrosses developed pure cerebellar dysfunction from the age of 7 to 8 weeks onward. It became progressively worse, but not fatal, between 1 and 2.5 months. Prenatal or perinatal infection with feline panleukopenia virus, inherited lysosomal storage diseases, including gangliosidosis and mannosidosis, and feline hereditary neuroaxonal dystrophy were excluded. Magnetic resonance imaging indicated that size of the cerebellum of diseased cats was markedly reduced. Cerebellar cortical degeneration, especially with extensive destruction of Purkinje cells, was observed microscopically., Conclusion: The disease was concluded to be cerebellar degeneration of a new clinical form in cats having an autosomal recessive mode of inheritance., Clinical Relevance: When cerebellar dysfunction is diagnosed in a cat, hereditary cerebellar degeneration of this type should be considered in the differential diagnosis.

Three of nine dairy calves born in the spring/summer wee severely ataxic at birth. Necropsy of the 3 affected calves revealed severe cerebellar degeneration (hypoplasia). Clinical signs were inapparent in the adult cows. Serum neutralization titers of the cows and calves indicated high bovine viral diarrhea titers.

We evaluated a kindred of Gordon Setters affected with inherited ataxia. Six adults and 4 pups clinically affected by the disease were examined. Pathologic studies were performed on a 3-year-old affected female dog and on a 2-month-old pup born to affected parents. The dogs were normal at birth; the 1st signs of neurologic dysfunction (wide-based stance and hypermetria) appeared between 6 and 10 months of age. As the disease progressed, increased tone of the extensor musculature, truncal ataxia, and nystagmus were noted. The disease had a slowly progressive course. The pathologic abnormalities were limited to the cortex of the cerebellum. There was atrophy with loss of Purkinje cells and granule cells affecting predominantly the vermis and paravermian regions of lobules IV, V, and VI. The study of the pedigree and our observations of the progeny of 2 affected dogs indicated that the mode of inheritance of this ataxia is compatible with an autosomal recessive trait.

Spongy degeneration of the CNS was diagnosed in 2 female Labrador Retriever littermates. The dogs had histories of progressive cerebellar ataxia and episodes of extreme extensor rigidity beginning at 4 and 6 months of age. One had a history of hearing difficulties. When examined at 9 months of age, both dogs had moderate ataxia and dysmetria of the head, trunk, and limbs, hyperreflexia with clonus, and extensor rigidity with episodes of exaggerated rigidity and opisthotonos. One dog was euthanatized and the other was monitored for 2 months, during which time her signs progressed to severe dysmetria, weakness, muscle atrophy, and rigidity with marked hyperreflexia. Necropsy of both dogs revealed astrocytic abnormalities and spongy degeneration of the white matter of the CNS. The clinical signs and postmortem findings were similar to the juvenile form of spongy degeneration in man.

Idiopathic feline vestibular syndrome, a peripheral vestibular deficit of unknown cause, was diagnosed in 75 cats at the New York State College of Veterinary Medicine Teaching Hospital from July 1975 to October 1984. Review of the medical records of these cats indicated that the syndrome was seen in more cats in July and August (P less than 0.001) than in other months. Clinical signs included head tilt, ataxia, rolling, rotatory or horizontal nystagmus, and occasional vomiting.