9 - Mucopolysaccharidoses

Abstract

This chapter provides an overview of mucopolysaccharidoses. There are a number of disorders affecting the skeleton that arise from failure of the normal breakdown of complex carbohydrates. These carbohydrates accumulate in the tissues and appear in excess in the urine. These disorders are rare but demonstrate well the relation between inherited metabolic disease and the skeleton. They may be divided into two main groups, according to the nature of the substances stored, namely, the mucopolysaccharidoses and the mucolipidoses. In the latter group, lipids accumulate in addition to mucopolysaccharides and oligosaccharides appear in excess in the urine, providing the alternative term, the oligosaccharidoses. Most people find that the mucopolysaccharidoses are more difficult to understand than those inherited disorders that involve collagen. This is because the chemistry of the mucopolysaccharides (glycosaminoglycans) is complex, because it is not understood how defects in their metabolism can be related to their clinical features, and because these clinical features overlap with a large number of other diseases such as the spondylo-epiphyseal dysplasias and mucolipidoses.