¹Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA

²Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA

Correspondence to: Dr M Haskins, University of Pennsylvania, School of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104-6051, USA

The genetic mucopolysaccharidoses (MPS) are a family of lysosomal storage diseases resulting from defective catabolism of glycosaminoglycans (GAGs). Echocardiographic abnormalities in dogs with MPS type VII (Sly syndrome, -glucuronidase deficiency) included mitral valve thickening and insufficiency, large aortic dimensions in both the long and short axes, and thickened aortic valves. Grossly, at post mortem examination, there was nodular thickening of the mitral valve, a prominent ductus diverticulum, and a dilated aorta with thickened walls. Histologically, cytoplasmic vacuolation was seen in cells of the mitral valves, coronary arteries, and aorta. By electron microscopy, the cells of the mitral valve were packed with electron-lucent cytoplasmic vacuoles. The mean residual activity of -glucuronidase in the aorta and myocardium was <1% of normal, the mean hexosaminidase a activity >2.5 times normal, and the mean GAG concentrations more than twice normal. In three MPS VII dogs that received heterologous BMT at 6 weeks of age, the echocardiographic abnormalities were improved, and the histopathologic and ultrastructural pathology was reduced. In the aorta and myocardium, the mean -glucuronidase activity of the BMT group was 4.5% and 11% of normal, respectively, and the hexosaminidase A activity and GAG concentrations were normalized. Bone Marrow Transplantation (2000) 25, 1289-1297.

bone marrow transplantation; cardiovascular; canine; lysosomal storage; mucopolysaccharidosis