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Metabolic Myopathies

Carnitine deficiency

What is carnitine deficiency?

Carnitine deficiency is one of a group of metabolic muscle diseases that interferes with the processing of food (in this case, fats) for energy production.

What are the symptoms of carnitine deficiency?

If confined to muscles, this disease causes weakness in the hips, shoulders, and upper arms and legs. The neck and jaw muscles also may be weak. Heart muscle weakness may occur.

In more severe cases, in which other tissues are affected, symptoms can include low blood sugar, fatigue, vomiting, abdominal pain, growth retardation, low weight, enlarged liver and episodes of brain function abnormalities.

What causes carnitine deficiency?

Carnitine deficiency may occur in response to a genetic mutation (gene defect) in the protein responsible for bringing carnitine into the cell (primary carnitine deficiency), or it may occur secondary to other metabolic diseases (secondary carnitine deficiency). See Causes/Inheritance for more.

What is the progression of carnitine deficiency?

The disease has its onset from infancy to early adulthood and is slowly progressive.

What is the status of research on carnitine deficiency?


  • development of enzyme replacement therapies; and
  • development of gene therapies.

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