Cystinosis

Abstract

Most lysosomal storage disorders result from deficiencies of acid hydrolases that degrade lipids, carbohydrates, or proteins. As a consequence of these defects, macromolecules accumulate within lysosomes. This stands in stark contrast to lysosomal storage disorders resulting from deficiency of small molecule transporters, in which an amino acid, sugar, or vitamin fails to exit the lysosome. The resulting diseases, corresponding to storage of cystine, sialic acid, or cobalamin, are cystinosis, Salla disease, and cobalamin F disease, respectively. This chapter deals with the first and most common of these lysosomal membrane transport disorders.