ABSTRACT
The lysosomal catabolism of glycans is an ordered mechanism which, at the moment, is difficult to explain. This chapter shows that stepwise modifications of the tridimensional structure of the oligosaccharides occur and that each removal of a mannose residue modifies that spatial conformation of the oligosaccharide formed so that the next mannose residue to be removed is well presented to the next a-mannosidase. Until 1895, date of the first description by Hurler of a storage disease due to an autosomal recessive genetic defect in lysosomal glycosidases involved in the catabolism of glycoconjugates, a syndrome called “gargoylism” was described. This syndrome was characterized by the following symptoms: mental retardation, facial dysmorphy, dysostosis multiplex, and vacuolated lymphocytes. The diagnosis of glycoproteinoses and the discovery of new types of glycoproteinoses are based on the systematic analysis of the material accumulated in urine of patients and in amniotic fluid at antenatal diagnosis.
