Mucopolysaccharides

Abstract

Mucopolysaccharides or glycosaminoglycans (GAGs) are polysaccharides, which consist of repeating disaccharide units. Deficiencies of certain lysosomal enzymes result in accumulation of GAGs in tissue and urine. All mucopolysaccharidoses (MPS) represent chronic, progressive disorders which exhibit a wide variety of clinical manifestations, from skeletal abnormalities to intellectual impairment. Diagnosis should be based on firm clinical observations before biochemical tests are initiated. A four-step process is then recommended. The first step should be a relatively unspecific screening test for urinary GAG excretion. The second step should be the differentiation of urinary GAGs by electrophoresis or thin-layer chromatography (TLC). In the third step the enzyme deficiency should be demonstrated. Finally, for future genetic counseling, the identification of the distinct mutations in both alleles should be considered. In this chapter, the dimethylene method as a urinary screening test, electrophoresis and TLC for GAG differentiation and the enzyme assays from leukocytes as well as dried blood will be introduced. Furthermore, pitfalls will be discussed and a short survey of alternative methods will be given. © 2008 Springer-Verlag.