A suspected new canine storage disease.

This paper describes three cases of what is probably a new form of storage disorder. The affected animals were English Springer Spaniels and they had developed progressive neurological signs when 2-3 years old. They had gross enlargement of the vagi and of the spinal nerves supplying the brachial plexus. By light microscopy in these nerves these were massive amounts of endoneurial loose fibrous tissue with dispersion of nerve fibres and many foamy phagocyte-like cells. In the central nervous system there was very severe cytoplasmic vacuolation of most neurones and neuroglia, perivascular phagocyte-like cells, loss of myelin, loss of Purkinje cells, numerous spheroids, hypertrophic astrocytes and fibrous astrocytosis. There was also foamy cytoplasmic vacuolation of renal convoluted tubules and pancreatic exocrine parenchyma and numerous foamy phagocyte-like cells in lymph node and lung. On ultrastructural examination membrane bound vacuoles were present in the cytoplasm of affected neurones and phagocyte-like cells. Most of the vacuoles were empty, some contained amorphous materials and some, in neurones, contained stacks of curved or straight lamellae. It is suggested that the stored material could be an oligosaccharide.