Upper motor neurone and descending tract pathology in bovine spinal muscular atrophy

The extent of neuropathology in a recently reported disease of Brown Swiss cattle, spinal muscular atrophy (SMA), was investigated with light and electron microscopy. Many regions of the central nervous system were sampled from 10 SMA-affected and three normal Brown Swiss calves. In addition to extensive necrosis of lower motor neurones there was extensive upper motor neurone degeneration and descending tract pathology. Since these abnormalities are also hallmarks of amyotrophic lateral sclerosis (ALS), SMA may be an animal model for that disease. There was also considerable vacuolar degeneration, which is a feature of the wobbler mouse and murine type C RNA virus-induced paralytic disease models of ALS.