There is a vast spectrum of clinical manifestations encountered in individuals with lysosomal storage diseases. Lysosomes are organelles that are involved in the degradation of intracellular proteins, recycled products and organelle in the cell. Lysosomal storage disorders occur when an enzyme necessary for breaking down these molecules is deficient, and, as a result, the substrate accumulates within the lysosomes of cells and may affect different organ systems. This is a longitudinal natural history study of patients with Gaucher disease and other storage disorders. Gaucher disease, the most common lysosomal storage disorder, results from the inherited deficiency of the enzyme glucocerebrosidase, which breaks down the lipid glucocerebroside. The disease is characterized by extremely variable phenotypes, with some patients presenting in childhood with virtually all the complications of Gaucher disease, while others remain asymptomatic into their eighth decade. Often patients with Gaucher disease develop hepatosplenomegaly, anemia, thrombocytopenia and bony problems. Gaucher disease has traditionally been divided into three clinical subtypes, delineated by the absence or presence of neurologic involvement and its progression: