Shetland Sheepdog leukodystrophy

Three litters of Shetland Sheepdog pups born to the same bitch and 2 differ ent sires were studied because of uncontrollable seizures or progressive ne urologic dysfunction. Four pups from the Ist litter, I from the 2nd litter, and 4 from the 3rd litter had severe diffuse spongy degeneration of the wh ite matter of the brain and spinal cord. An inherited basis for this syndro me was suspected. The purpose of this study was to evaluate the pups with c urrently available screening tests for the metabolic, biochemical, infectio us, and toxicologic causes of leukodystrophy seen in humans and animals. Co mputed tomography scans revealed diffuse hypomyelination in the affected pu p. Complete postmortem examination. including histopathology and electron m icroscopy, delineated a leukodystrophy resembling human Canavan's disease, but amino acid and organic acid metabolism abnormalities were not detected. No etiology for Shetland Sheepdog leukodystrophy has been found, but this condition represents another familial disease in the purebred dog populatio n.