What is Glycogen Storage Disease?

Glycogen storage disease is an inherited disorder that affects metabolism. Individuals with the condition are either unable to create glycogen or their bodies cannot convert stored glycogen to usable glucose. Most medical authorities believe that there are at least 11 different forms of glycogen storage disease, each occurring in one or more specific parts of the body, especially in the liver, muscles, or intestines. Many people with a form of the disease are subject to hypoglycemia, muscle cramps and weakness, and possible failure of vital organs like the heart or kidneys.

Glucose is a type of blood sugar that provides the body's cells with the energy. Glucose is digested and processed from many different foods and liquids, introduced into the bloodstream, and carried to cells throughout the body. After meals, healthy bodies store excess glucose for later use by converting it to glycogen. When a person needs extra energy, enzymes activate glycogen molecules and convert them back into usable glucose. An individual who has a glycogen storage disease, however, may not be able to convert glycogen into glucose because of an enzyme deficiency.

A glycogen storage disease may manifest in a single part of the body, such as the liver or certain muscles, or be more widespread. The different types of storage diseases are classified by the organs or muscles affected, the type of enzyme deficiency, and the symptoms that are present. Since glycogen storage diseases are congenital, symptoms are usually recognized in infancy. A baby with a form of the disease might suffer from hypoglycemia, a swollen liver, muscle cramps, aches, and a lack of energy. Depending on the specific enzyme deficiency, a child may be subject to anemia, delayed or stunted growth, renal failure, heart failure, or even death.

Pediatricians and specialists usually diagnose glycogen storage disease by conducting physical examinations, investigating family history, and collecting blood and urine samples for laboratory analysis. The presence or absence of glucose, enzymes, and cholesterol in blood and urine screenings allow doctors to determine the specific type of a glycogen storage disease. Once a diagnosis has been made, treatment plans can be considered and enacted immediately in an effort of preventing long-term health problems.

Enzyme replacement therapy is an effective form of treatment for some types of glycogen storage diseases. A doctor injects a solution containing specific enzymes directly into a patient's bloodstream, promoting better regulation of glycogen levels and increasing the body's ability to use glucose. Treatment may also involve careful monitoring of dietary intake to prevent hypoglycemia and related health issues. Babies need frequent feedings of foods that are high in carbohydrates and free from sucrose and lactose in order to promote healthy glucose production. Medical researchers are continuously experimenting with various intravenous and oral medications in hopes of finding a more effective means of treatment for glycogen storage diseases.