The disease is called Gaucher disease, and it is the most common of the sphingolipidoses; its incidence in the general population is ∼1:2500. This class of disease results from defective hydrolysis of membranecomponents, sphingolipids , that are normally turned over in the cell by hydrolytic breakdown inthe lysosomes. The sphingolipids are lipid molecules with attached carbohydrate groups. A failure to beable to remove glucose from these molecules results in their accumulation in the lysosomes. In fact, over a few years, the cells which have rapid membrane turnover, such as the liver and spleen, become engorgedwith this lipid breakdown product. Clinically the patients have a large liver and spleen and may show signs of mental deterioration if much of the lipid accumulates in the brain as well.