Canine inherited ataxia.

A previously unrecognized canine disorder consists of familial cortical cerebellar degeneration with many characteristics that are similar to inherited ataxias in humans. The disease occurs in Gordon setters and appears to be inherited as an autosomal recessive trait. The dogs appear normal during the first 6 months of life, but between 6 and 12 months of age they develop a broad-based gait and dysmetria, followed by truncal ataxia. Nystagmus occurs late. The disorder is slowly and insidiously progressive. Neuropathological examination shows atrophy of the cerebellar cortex, particularly the pars intermedia. There is loss of Purkinje and granule cells, more severe in older dogs. Other parts of the neuraxis appear normal. These pathological changes resemble those of the familial human cerebellar cortical atrophies.