Lysosomal storage disorders (LSDs) is a term used to describe a group of diseases caused by a defect in lysosome enzymes. Lysosomes act as the "recycling center" of each cell, breaking down unwanted materials into simple waste products. The lack of certain lysosomal enzymes causes a buildup of waste products in many cells of the body.
The clinical symptoms depend on the cells and tissues that use the deficient enzyme and if any working amount of enzyme is present. The types of LSDs are named for the substance that builds up in the cells.
Mucopolysaccharidoses (MPS) disorders are the most common (1 in 25,000 births) of the LSDs. There are more than 40 known types, including those known by the common names listed below:
- Fabry disease - causes kidney and heart problems, pain, and a skin rash
- Gaucher disease - causes the spleen to enlarge, anemia, and bone lesions if untreated; can also cause progressive neurologic problems
- MPS disorders (Hurler/Hunter/Morquio)
- Niemann-Pick B disease - leads to enlargement of the spleen and liver, as well as lung disease
- Pompe disease - a storage disease in which glycogen builds up in the liver, heart and muscle, and can be fatal if it develops in infancy (also known as acid maltase deficiency)
- Tay-Sachs disease - a lysosome storage disease that occurs more commonly in people of Eastern European Ashkenazi descent. It causes degeneration of the brain in infants with early death.