Glycogen storage disease type 2

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Disease Overview

Glycogen storage disease type 2, also known as Pompe disease or acid maltase deficiency disease, is an inherited metabolic disorder.[864][865][866] While glycogen storage disease type 2 is a single disease, it may be classified in 2 forms according to the rates of disease progression, its severity and the age at which symptoms start. The classic infantile-onset starts before 12 month of age and involves the heart muscle (myocardiopathy). The later-onset form may start before 12 months of age (non-classic infantile-onset), or after 12 months of age, but does not affect the heart. Muscle weakness is a main symptom in all forms. The infantile-onset is the most severe form and, if untreated, it may lead to death from heart failure in the first year of life. The late-onset form is usually milder, but if untreated may lead to severe breathing problems.[864][11724] 

Glycogen storage disease type 2 is caused by variants (mutations) in the GAA gene which have instructions to produce the enzyme acid alpha-glucosidase (acid maltase), needed to break down glycogen, a substance that is a source of energy for the body. The enzyme deficiency results in the accumulation of glycogen inside lysosomes, structures within cells that break down waste products within the cell. Accumulation of glycogen in certain tissues, especially muscles, impairs their function.[864][865][866]

In 2006, the U.S. Food and Drug Administration (FDA) approved the enzyme replacement therapy Myozyme as a treatment for all patients with glycogen storage disease type 2. Another similar drug called Lumizyme has recently been approved for the treatment this disease.[864][866][8904] Additional treatment of Pompe disease is symptomatic and supportive and may include respiratory and feeding support and physical therapy.[864]
 


Synonyms

  • Pompe disease
  • Acid maltase deficiency disease
  • Aglucosidase alfa
  • Alpha-1,4-glucosidase deficiency
  • Cardiomegalia glycogenica diffusa
  • Deficiency of alpha-glucosidase
  • GSD II
  • Deficiency of lysosomal alpha-glucosidase

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National Organization for Rare Disorders