Acral mutilation and nociceptive loss in English Pointer dogs

Summary Acral mutilation and analgesia occurred in three of a litter of nine pups produced by a mating of clinically normal English Pointer dogs. Post-mortem studies on one of the affected pups revealed changes at the level of the primary sensory neuron which included: a reduction in spinal ganglia size, a 22–50% deficiency of ganglionic neurons, and a disproportionately large population of small sensory cell bodies. The only change noted in the spinal cord occurred in the dorsolateral fasciculus where reduced fiber density appeared to correlate well with the observed nociceptive defect. Light- and electron-microscopic examination of spinal roots, ganglia, and peripheral nerves provided evidence of myelinated and unmyelinated fiber degeneration. The neuronal degeneration, however, appeared quantitatively inadequate to account for the deficiency of sensory cell bodies. It was concluded that this mutilating acropathy was a manifestation of a sensory neuropathy in which the neuronal deficiency resulted from insufficient development and slowly progressive, postnatal degeneration.The clinical and pathologic findings in this canine disorder were compared with those reported in hereditary sensory neuropathies of man and other animals.This work was supported by NIH grant NS-14242-01, contact RR-9-2102, and Biomedical Research Support Grant funds