Lysosomal storage diseases

Abstract

Lysosomal storage disorders (LSDs), over 40 different diseases, are now considered treatable disorders. Only a few short years ago, Lysosomal storage disorders were seen as interesting neurodegenerative disorders without any potential for treatment. Effective treatment strategies such as bone marrow transplantation (BMT), enzyme replacement therapy (ERT), and glycolipid synthesis inhibition have been developed in the last 20 years and continue to be researched and evaluated. Bone marrow transplantation began approximately 15 years ago and has shown benefit for some of the lysosomal storage disorders. In order to be effective, the transplant must be performed early in the course of the disease, before the development of irreversible neurologic damage. Diseases such as Hurler appear to respond to BMT, however, improvement in bone disease is much less vigorous than responses in other organs. Krabbe disease responds if the transplant is performed before irreversible signs of neurologic damage appear. Metachromatic leukodystrophy may respond if the transplant can be performed early enough although peripheral nerve findings appear to progress. Other diseases, eg, GM1- and GM2-gangliosidoses do not appear to be altered by BMT. Despite its high cost, ERT has been very effective treatment for type I (non-neuronopathic) Gaucher disease. Enzyme replacement therapy for other LSDs, including ERT for Fabry and Pompe diseases, which are planned to be imminently introduced, and other enzymes such as for Morquio and Hunter diseases that are in the study phases, may be marketed in the very near future. Glycolipid inhibitors, such as N-butyldeoxynijirimycin (OGS-918), have been effective in reducing the liver and spleen volume in type I Gaucher disease. These oral inhibitors may prove to be important adjuncts to ERT and provide the advantage of being able to cross the blood/brain barrier, which limits enzyme access to brain. Currently, clinical studies are being conducted on patients with type III Gaucher disease and Fabry disease using OGS-918. Other, potentially more specific, glycolipid inhibitors are being developed.

Direct Multiplex Assay of Lysosomal Enzymes in Dried Blood Spots for Newborn Screening

“…Depending on the disorder, they can manifest from birth to adulthood. Until recently, there has been minimal therapeutic intervention available to alter the natural course of the disorders, but with the recent availability of commercial preparations of recombinant enzymes, selective lysosomal disorders are now amenable to therapeutic intervention (7)(8)(9). There is excellent documentation that enzyme replacement therapy for Gaucher disease [acid ␤-glucocerebrosidase (ABG) deficiency] and Fabry disease [acid ␣-galactosidase A (GLA) deficiency] may alter the natural progression of the disorders and improve the clinical phenotype.…”

Untitled

“…From these lines of evidence, we propose that anti-inflammatory therapy by a phosphodiesterase inhibitor during an appropriate period, may be a reliable supportive treatment for Krabbe's disease for which there is no effective treatment except bone marrow transplantation [6,23,47-49]. …”

Metabolic disorders: an overview and key messages for pharmacists

“…Bone marrow transplantation alleviates some of the disorders by introducing donor cells that can express the enzyme 13. Enzyme replacement therapy represented a major advance for this patient group.…”