Glycogen storage disease type II (also called Pompe disease or acid maltase deficiency) is a rare genetic disorder caused by a deficiency in the enzyme acid alpha-glucosidase (GAA), which is needed to break down glycogen, a stored form of sugar used for energy. It is the only glycogen storage disease with a defect in lysosomal metabolism, and was the first glycogen storage disease to be identified—in 1932. The build-up of glycogen causes progressive muscle weakness throughout the body and affects various body tissues, particularly in the heart, skeletal muscles, liver and nervous system. Transmission is by autosomal recessive inheritance. Children have a 1 in 4 chance of inheriting the disease when both parents carry the abnormal gene. It is estimated to occur in about 1 in 40,000 births. The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... The International Classification of Diseases for Oncology (ICD-O) is a domain specific extension of the International Statistical Classification of Diseases and Related Health Problems for tumor diseases. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... MedlinePlus (medlineplus. ... eMedicine is an online clinical medical knowledge base that was founded in 1996. ... The Diseases Database is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... Ribbon diagram of the catalytically perfect enzyme TIM. An enzyme is a protein that catalyzes, or speeds up, a chemical reaction. ... Electron micrograph of a section of a liver cell showing glycogen deposits as accumulations of electron dense particles (arrows). ... Magnified view of refined sugar crystals. ... Glycogen storage disease is any one of several inborn errors of metabolism that result from enzyme defects that affect the processing of glycogen synthesis or breakdown within muscles, liver, and other cell types. ... Glycogen storage disease is any one of several inborn errors of metabolism that result from enzyme defects that affect the processing of glycogen synthesis or breakdown within muscles, liver, and other cell types. ... The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. ... A top-down view of skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ... The liver is one of the largest internal organs of the human body. ... The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and processes input from the senses, and initiates actions. ...

Variants

Pompe disease has three forms defined by age of onset and progression of symptoms:

Infantile, or early onset, is noticed shortly after birth. Symptoms include severe lack of muscle tone, weakness, and enlarged liver and heart. Mental function is not affected. Development appears normal for the first weeks or months but slowly declines as the disease progresses. Swallowing may become difficult and the tongue may protrude and become enlarged. Most children die from respiratory or cardiac complications before 2 years of age. Look up birth in Wiktionary, the free dictionary. ... Many animals have longer and more flexible tongues than humans. ...

Juvenile onset symptoms appear in early to late childhood and include progressive weakness of respiratory muscles in the trunk, diaphragm and lower limbs, as well as exercise intolerance. Intelligence is normal. Most patients do not live beyond the second or third decade of life. A diaphragm is some sort of separating membrane. ... Intelligence is usually said to involve mental capabilities such as the ability to reason, plan, solve problems, think abstractly, comprehend ideas and language, and learn. ...

Adult onset symptoms also involve generalized muscle weakness and wasting of respiratory muscles in the trunk, lower limbs, and diaphragm. Many patients report respiratory distress, headache at night or upon waking, diminished deep tendon reflexes, and proximal muscle weakness, such as difficulty in climbing stairs. Intellect is not affected. A small number of adult patients live without major symptoms or limitations

Treatment

Cardiac and respiratory complications are treated symptomatically. Physical and occupational therapy may be beneficial for some patients. Alterations in diet may provide temporary improvement but will not alter the course of the disease. Genetic counseling can provide families with information regarding risk in future pregnancies.

Prognosis

The prognosis for individuals with Pompe disease varies according to the onset and severity of symptoms. The disease is particularly lethal in infants and young children.

External links

• Pompe's disease page at Online Mendalian Inheritance in Man
• The website of the Pompe's Group of the Association for Glycogen Storage Disease (UK)
• International Pompe Association - A federation of Pompe disease patient's groups world-wide.