Fast Five Quiz: Glycogen Storage Disease Type II (Pompe Disease)

Wayne E. Anderson, DO


August 06, 2021

Muscle weakness is the most common symptom in all forms of the disease. Glycogen accumulation within the muscles, peripheral nerves, and the anterior horn cells causes this weakness.

The classic infantile form of glycogen storage disease type II is characterized by severe muscle weakness (myopathy) and abnormally diminished muscle tone (hypotonia) without muscle wasting. Additional abnormalities may include cardiomegaly, hepatomegaly, and macroglossia. Affected infants may also have poor feeding, failure to thrive, breathing problems, and hearing loss. Most infants with glycogen storage disease type II cannot hold up their heads or move normally. Without treatment, progressive cardiac failure usually causes life-threatening complications by the age of 12 to 18 months.

The nonclassic infantile form of glycogen storage disease type II usually presents within the first year of life. Patients older than 6 months have motor delays and/or slowly progressive muscle weakness. Death may result from ventilatory failure in early childhood. In this form, cardiac disease is not a major cause of morbidity; however, cardiomegaly may be seen. Initial symptoms may include delayed motor skills (crawling, sitting) and myopathy. Unlike the classic infantile form, cardiac failure does not typically occur.

In the late-onset form of glycogen storage disease type II, symptoms may not be evident until childhood, adolescence, or adulthood. This form is usually milder than the infantile-onset form of the disorder. Most individuals experience progressive muscle weakness, especially in the legs and the trunk, including the diaphragm, the rib cage muscles, and the abdominal muscles. They may ultimately die of respiratory failure.

Learn more about the symptoms of glycogen storage disease type II.


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