Beta-Mannosidosis, and inherited disorder of glycoprotein metabolism, occurs in the caprine species, but has not yet been identified in man. Deficiencies of tissue and plasma Beta-mannosidase activities, and the accumulation and the excretion of a Man (Beta1-4)G1cNAc (Beta1-4)G1cNAc trisaccharide and Man (Beta1-4)GlcNAc disaccharide, are associated with profound neonatal neurological deficits, myelin deficiency and ubiquitous cytoplasmic lysosomal storage vacuoles. The metabolic basis and the pathogenesis of beta-mannosidosis will be investigated in affected goats to be produced from the Beta-mannosidosis colony. I. Enzyme studies. Acidic and neutral Beta-mannosidases from the liver of normal, carrier and affected goats will be purified with conventional purification techniques and immunoaffinity chromatography. Immunochemical, biochemical and physical properties of the normal gene product will be characterized in order to define the molecular defect in the abnormal gene product. Enzyme activities and substrate specificities will be determined by incubation with artificial and natural substrates to be isolated from affected tissues and urine. II. Oligosaccharide studies. Novel complex oligosaccharides with Beta-mannose residues, identified in preliminary studies of affected tissues, will be isolated by conventional gel permeation and high pressure liquid chromatography and will be characterized by mass spectrometry of the permethylated intact oligosaccharide alcohols. Carbohydrate composition analysis, methylation linkage studies and enzymatic degradations will be performed. These methods will also be used to isolate, characterize and compare the oligosaccharides in tissues from affected and normal caprine fetuses. III. Clinical, morphological and genetic studies. The phenotypes and genotypes of the clinically normal, affected and carrier states will be characterized. Genetic markers will be identified to confirm family relationships and to define linked markers. Pre-and postnatal clinical, morphological and biochemical perturbations will be compared to define the development of Beta-mannosidosis. Special morphological studies will be performed to define the pathogenesis of the sesorineural deafness and other neurological deficits. Results will be assessed to clarify the metabolic basis and the pathogenesis of this lethal inherited disease. The outcomes of these studies will facilitate our understanding of normal and perturbed glycoprotein metabolism and will provide the basis for diagnostic and therapeutic approaches to the putative human Beta-mannosidosis counterpart.
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