Glycogen storage disease type II, also known as acid maltase deficiency or Pompe disease, is characterized by an enzyme acid maltase deficiency. The body uses the enzyme acid maltase to metabolize glycogen for energy. Among all the glycogen storage diseases, this is the only one with a lysosomal metabolism deficiency.

Diagnostic procedures include electromyography, muscle biopsy, ischemic forearm test, and creatine kinase levels. A patient's medical history must also be analyzed, and he must also have a physical examination. A biochemical assay will conclude the diagnostic findings.

Treatment depends on which symptoms are being experienced by patients, such as physical therapy, occupational therapy, as well as respiratory and cardiac treatments. Families may avail of genetic counseling for information on future pregnancies. Myozyme is a recently FDA-approved medication, the first developed to effectively treat Pompe disease. However, the treatment must be taken for the whole of the patient's life and is quite costly.

Symptoms of GSD type II are classified according to time of onset. Infantile, also known as early onset, is characterized by enlarged heart and liver, lack of muscle tone, and weakness. These symptoms are noticed usually not long after birth. Development is not affected until a few months after birth, and will worsen as the disease progresses. However, mental function remains unaffected. Juvenile onset symptoms are exhibited anytime from early to late childhood. These include weakness of lower limbs, diaphragm, progressive weakness of respiratory muscles in trunk, and intolerance to exercise. Adult onset symptoms include degeneration of respiratory muscles in trunk, diaphragm, and lower limbs, as well as muscle weakness. In many cases, headaches during nighttime or waking time occur, respiratory distress, muscle weakness, and decreased deep tendon reflexes.

The disease is caused by its autosomal recessive nature.

glycogenstoragediseasetypeii