Advances in Therapies for Mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are severe, inherited metabolic diseases, classified among lysosomal storage diseases (LSDs). The presence of pathological variants of genes coding for enzymes involved in the degradation of glycosaminoglycans (GAGs) is a primary cause of each MPS type, and accumulation of these compounds is a characteristic feature of MPS. Depending on the kind of defective enzyme and the type of stored GAG(s), 12 classical types are distinguished, and a few other related diseases, whose classification is unclear. Although there is no fully effective cure for MPS, several kinds of therapeutic approaches have been proposed to treat these diseases, and some of them have been introduced into clinical practice. In this review article, we present and discuss very recent advances in developing various therapies for MPS, also indicating problems and limitations. This paper focuses on enzyme replacement therapy (ERT), cell- and gene-based therapies (including hematopoietic stem cell transplantation and gene therapy), inhibition of GAG synthesis, and some other newly developed therapeutic approaches. Perspectives on MPS therapies are also discussed.