Abstract
Lysosomal storage diseases (LSDs) form a group of more than 70 rare inherited metabolic diseases, usually caused by a malfunction of some of the lysosomal enzymes. The aim of this review is to introduce enzyme replacement therapy (ERT) which gained an indispensable role in the therapy of LSDs.
ERT is based upon replacement of the defective enzyme by a recombinant protein administred in a 2-4 hour infusion once a week or once a fortnight. This therapy is currently available for seven LSDs: Gaucher disease, Fabry disease, Pompe disease and mucopolysaccharidoses I, II, IVA and VI.
ERT significantly affects visceral manifestations of the diseases (hepatomegaly, splenomegaly, vital lung capacity, muscle weakness, anaemia, gastrointestinal disorders etc.), yet it is not effective in treating the central nervous system (CNS) involvement and only a small effect is observed in treating disease manifestations in bones, cartilage and heart valves. An immune reaction with clinical presentation of an allergic reaction and therapy effectiveness decrease can occur with a portion of patients.
Other modalities for LSDs therapy are concisely mentioned: haematopoietic stem cell transplantation, substrate reduction therapy, chaperons and gene therapy. Conclusion: ERT slows the progression of the disease and markedly alters its natural course, improves quality of life and prolongs patients' lifespan.
The limitations include insufficient effect in some tissues, possible allergic reactions and great financial demands. An essential presumption for effectiveness and success of ERT is its early initiation following quick diagnosis of the disease.