Enzyme replacement therapy for mucopolysaccharidosis I: laronidase

Mucopolysaccharidosis type I (MPS I) is a storage disorder caused by the deficiency of the lysosomal enzyme α-L-iduronidase. MPS I has a chronic progressive evolution with multisystemic symptomatology and wide clinical variability, with its main manifestations in the skeletal, respiratory, cardiac and neurological systems. Until recently, therapeutic options for MPS I were limited to hematopoietic stem cell transplantation for severe cases, and palliative care. Laronidase (Aldurazyme®, BioMarin/Genzyme, CA, USA), a synthetic variant of the human α-L-iduronidase, is a specific treatment for MPS I. Enzyme replacement therapy with intravenous infusion of laronidase aims to reduce and/or prevent the accumulation of glycosaminoglycans (dermatan and heparan sulfate), which is probably the most important, although possibly not the only, cause of the clinical manifestations of MPS I. This article reviews the data published to date on the clinical indications and user experience of laronidase in patients with MPS I.