Enzyme replacement therapy is given successfully in a) Fabry’s disease b) Gaucher disease c) Sanfilippo syndrome d) Pompe disease Answer: Gaucher disease Explanation: Gaucher disease: Gaucher disease is a lipid storage disease characterized by the deposition of glucocerebroside in cells of the macrophage- monocyte system. The disorder results from the deficiency of a specific lysosomal hydrolase, glucocerebrosidase. Enzyme replacement therapy (ERT) for type 1 Gaucher disease is now available. Most patients receive the recombinant enzyme. This preparation is highly effective in reversing the visceral and hematologic manifestations of Gaucher disease. Fabry disease: Fabry disease is an X-linked lysosomal disorder that leads to excessive deposition of neutral glycosphingolipids in the vascular endothelium of several organs and in epithelial and smooth muscle cells. Deficiency of alpha-galactosidase-A activity leads to lysosomal accumulation of glycosphingolipids, predominantly the cerebroside trihexosides. Two enzymes, agalsidase-alpha and agalsidase-beta reportedly help in normalizing renal function, cardiac function, and cerebro- vascular flow. Pompe disease: In some glycogen storage disorders, clinical trials have successfully used treatment involving replacement of the enzymes that are deficient or not working normally. For example, in glycogen storage disorder type II (Pompe disease), this treatment has been shown to help reverse the heart problems and muscle weakness that can occur. For the infantile form of Pompe disease, a recombinant enzyme replacement was approved by the FDA. Sanfilippo syndrome: Sanfilippo syndrome or Mucopolysaccharidosis III (MPS-III) is a rare autosomal recessive lysosomal storage disease. It is caused by a deficiency in one of the enzymes needed to break down the glycosaminoglycan heparan sulfate (which is found in the extra-cellular matrix and on cell surface glyco-proteins). No treatment for the underlying cause is available. Medical treatment is supportive and is directed toward improving the patient’s quality of life.