Enzyme replacement therapies in lysosomal storage diseases

Lysosomal storage diseases (LSDs) comprise about 50 unique monogenic autosomal or X-linked diseases with an estimated combined incidence of 1 in 7,000 to 8,000 live births. They occur secondary to genetic mutations that result in deficiency or reduced activity of native intracellular enzymes that catabolize biological macromolecules. These enzyme defects result in accumulation of specific macromolecular compounds within lysosomes in various tissues and organs, causing progressive damage that can become life-threatening in some diseases. LSD management traditionally involved supportive care measures tailored to disease stage, the organs and systems involved, and the degree of impairment. However, enzyme-replacement therapy (ERT) is now commercially available for six LSDs, typically used lifelong with traditional management practices for each.