The Study on Glycoproteins in the Liver of Patients with Inherited Lysosomal Storage Disorder

The hepatic sugar material of an inherited lysosomal storage disorder was studied. The pathological livers studied were obtained from a case of GM1-gangliosidosis type II, two cases of I-cell disease, a case of a new type of mucolipidosis with β-galactosidase deficiency, a case of Hunter syndrome and a case of Morquio ndrome. Five other normal livers from autopsy cases were used for a control study. The results were as follows; 1. GM1-gangliosidosis type II: the main substance of accumulation in the liver was glycoproteins with glycosaminoglycans also slightly accumulated. 2. New type of mucolipidosis: the accumulation of crude free oligosaccharides was evidently increased, its amount being 65mg/10g of wet liver weight. The molecular weight of this oligosaccharide was estimated to be approximately 2,500, and was composed of galactose, mannose and glucosamine. The oligosaccharides were fractionated to asialo- and sialo- substances. 3. I-cell disease: there were no accumulations of free oligosaccharides and glycoproteins in the liver, however, sialic acid in the water soluble sugar fraction was remarkably increased. 4. Hunter syndrome and Morquio syndrome: the main substance of accumulation in the liver was glycosaminoglycans with glycoproteins also present. From these studies, it was shown that glycoproteins and glycosaminoglycans were acccmulated in the liver of patients with GM1-gangliosidosis type II and Mucopolysaccharidoses, which supports the “multicomponent storage hypothesis”due to secondary effects of lysosomal enzyme deficiency. It is important to prove free oligosaccharides from the liver of a patient with this new type of mucolipidosis, because it is considered that pursuit of abnormal accumulated material will bear a very significant meaning in clarifying the metabolic pathway of inherited lysosomal disorders in addition to enzymati