This disease is a metabolic muscle disorder, a group of diseases that interferes with the processing of food (in this case, carbohydrates) for energy production.
This disease principally affects the liver. It causes swelling of the liver, slowing of growth, low blood sugar levels and, sometimes, seizures.
In children, these symptoms often improve around puberty. Muscle weakness may develop later in life, and is most pronounced in the muscles of the forearms, hands, lower legs and feet. Weakness often is accompanied by loss of muscle bulk and exercise intolerance. The heart can be affected as well.
The disorder is caused by a defect in the debrancher enzyme gene, which interferes with the breakdown of glycogen (stored sugar) in the muscles and liver. For more, see Causes/Inheritance.
This disease can begin anywhere from infancy to the 50s and is slowly progressive. The infantile-onset form may be life-threatening in childhood.
Researchers on metabolic diseases of muscle are making progress on a number of fronts, including: