Lysosomal storage disorders (LSDs) are a group of about 50 rare inherited metabolic disorders that result from defects in lysosomal function. New lysosomal storage disorders continue to be identified every day. They are characterized by an abnormal build-up of various toxic materials in the body's cells as a result of enzyme deficiencies. While clinical trials are in progress on possible treatments for some of these disorders, there is currently no approved treatment for many of them, which is why we are dedicating our efforts to three different lysosomal storage disorders: Fabry disease, alpha-mannosidosis, and nephropathic cystinosis.1,2