Hereditary canine spinal muscular atrophy: canine motor neuron disease.

Motor neuron diseases, manifest as weakness and atrophy of skeletal muscles, occur in infancy, childhood, and adult life. Some forms of this disease are inherited. Motor neurons are selectively affected and exhibit cytoskeletal pathology, primarily enlargements of proximal axons by accumulations of transported neurofilaments. A motor neuron disease, hereditary canine spinal muscular atrophy, has been discovered in Brittany spaniels. The disease is inherited as an autosomal dominant characteristic and shows striking clinical and pathological features in common with human motor neuron disease. The availability of this excellent animal model of the human condition has allowed neurobiological investigations of the dynamics of structural and chemical pathologies of vulnerable neurons.