Feline hereditary neuroaxonal dystrophy.

A newly recognized neurologic disorder of cats is described. It is characterized clinically by an abnormal coat color and development of progressive ataxia during infancy. Breeding experiments indicate that the disease is inherited in an autosomal recessive manner. Pathologically, neurologic lesions closely resemble those described in infantile neuroaxonal dystrophy of children. The most prominent microscopic alterations were marked ballooning of nerve cell processes within specific regions of the brain stem and atrophy of the cerebellar vermis. Ultrastructural studies demonstrated that dystrophic axons contained electron-dense flocculent material, multilaminated membrane-bound osmiophilic bodies and filaments. Examination of the inner ears revealed depletion of neurons in the spiral ganglia and homogeneous eosinophilic bodies within the spiral ganglia, nerve fiber tracts and organ of Corti. The concept that the disease represents an inborn error of metabolism was supported by finding axonal dystrophy in neonates prior to development of cerebellar atrophy or recognition of clinical symptoms.