Glycoprotein lysosomal storage disorders: alpha- and beta-mannosidosis, fucosidosis and alpha-N-acetylgalactosaminidase deficiency

Biochim Biophys Acta. 1999 Oct 8;1455(2-3):69-84. doi: 10.1016/s0925-4439(99)00077-0.


Glycoproteinoses belong to the lysosomal storage disorders group. The common feature of these diseases is the deficiency of a lysosomal protein that is part of glycan catabolism. Most of the lysosomal enzymes involved in the hydrolysis of glycoprotein carbohydrate chains are exo-glycosidases, which stepwise remove terminal monosaccharides. Thus, the deficiency of a single enzyme causes the blockage of the entire pathway and induces a storage of incompletely degraded substances inside the lysosome. Different mutations may be observed in a single disease and in all cases account for the nonexpression of lysosomal glycosidase activity. Different clinical phenotypes generally characterize a specific disorder, which rather must be described as a continuum in severity, suggesting that other biochemical or environmental factors influence the course of the disease. This review provides details on clinical features, genotype-phenotype correlations, enzymology and biochemical storage of four human glycoprotein lysosomal storage disorders, respectively alpha- and beta-mannosidosis, fucosidosis and alpha-N-acetylgalactosaminidase deficiency. Moreover, several animal disorders of glycoprotein metabolism have been found and constitute valuable models for the understanding of their human counterparts.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Carbohydrate Sequence
  • Congenital Disorders of Glycosylation / enzymology*
  • Disease Models, Animal
  • Fucosidosis / enzymology*
  • Fucosidosis / genetics
  • Glycoside Hydrolases / deficiency
  • Hexosaminidases / deficiency*
  • Humans
  • Molecular Sequence Data
  • Phenotype
  • alpha-Mannosidosis / enzymology*
  • alpha-Mannosidosis / genetics
  • alpha-N-Acetylgalactosaminidase


  • Glycoside Hydrolases
  • Hexosaminidases
  • NAGA protein, human
  • alpha-N-Acetylgalactosaminidase