Canine inherited hypertrophic neuropathy: clinical and electrodiagnostic studies.

Clinical and electrodiagnostic features of acute and chronic canine-inherited hypertrophic neuropathy were studied in 20 affected dogs. The age of onset was consistently between 7.5 and 10 weeks of age. Affected pups had rapidly developing limb weakness accompanied by muscle hypotonia and hyporeflexia. There was no clinical evidence of cranial nerve dysfunction. Pups that did not develop limb contractures later regained some strength and became clinically stable for long periods, although they always remained weak. Progressive slowing of nerve conduction velocities occurred during the development of clinical signs of limb weakness. Temporal dispersion of evoked muscle action potentials was present in more chronically affected dogs. Transient spontaneous activity was present in muscles of affected dogs examined by electromyography. An autosomal recessive mode of inheritance was supported by the results of breeding studies.