Update on glycogen storage disease: a brief review of the main disorders.

A glycogen storage disease (GSD) is a metabolic disorder caused by a deficiency of an enzyme or transport protein affecting glycogen synthesis, glycogen breakdown, or glucose breakdown, typically in muscles and/or liver cells. Several enzymes are required for the processes of glycogenesis and glycogenolysis. Glycogen storage diseases happen when a person doesn't have one or more of these enzymes. GSD in almost all cases is genetic (In exceptional cases, it can be environmental, like GSD in livestock). Genetic GSD results mainly from inborn error in carbohydrate metabolism, where genetically faulty or malfunctioning enzymes or transport proteins are involved. It has many different types and diagnoses depending upon history, physical examinations and more specifically, blood tests and biopsies for related disturbances and genetic testing wherever mutations are being suspected. It is very important to distinguish the different types so that the patient receives the correct treatment. To even summarize the treatment modalities of the different sub-groups was beyond the scope of this study. We hope that it will elucidate better approaches and techniques amongst collaborative team members from the medical fraternity.