Fabry disease is an X-linked inborn error of glycosphingolipid catabolism caused by the deficient activity of the lysosomal enzyme, α-galactosidase A (α-Gal A). This enzymatic defect results in the progressive accumulation of GL-3 and related glycosphingolipids with terminal α-galactosyl moieties in the lysosomes of endothelial, epithelial, perithelial, and smooth muscle cells throughout the body. In classically affected males who have little, if any, α-Gal A activity, the glycosphingolipid deposition in the vascular endothelium is responsible for the major clinical manifestations of the disease, including angiokeratomas, acroparesthesias, and hypohidrosis. With advancing age, the progressive vascular glycosphingolipid accumulation leads to renal failure, cardiac and cerebrovascular disease, and early death. Based on the United States and European dialysis and transplantation registries, most classically affected males go into renal failure between the ages of 35 and 45 years. Prior to the advent of renal transplantation and dialysis, the average age of death for classically affected males in one series was 41 years. The incidence of classical Fabry disease is estimated to be ˜1 in 40,000–60,000 males.