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Genetic and Rare Diseases Information Center (GARD)

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Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes

Other Names for this Disease
  • MELAS syndrome
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What are the signs and symptoms of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS)?

The signs and symptoms of MELAS often appear in childhood following a period of normal development. Early symptoms may include muscle weakness and pain, recurrent headaches, loss of appetite, vomiting, and seizures. Most affected individuals experience stroke-like episodes beginning before age 40. These episodes may involve temporary muscle weakness on one side of the body, altered consciousness, vision abnormalities, seizures, and severe headaches resembling migraines. Repeated stroke-like episodes can progressively damage the brain, leading to vision loss, problems with movement, and a loss of intellectual function.[1]

Many people with MELAS have a buildup of lactic acid in their bodies (lactic acidosis). This can lead to vomiting, abdominal pain, extreme fatigue, muscle weakness, and difficulty breathing. Involuntary muscle spasms, impaired muscle coordination, hearing loss, heart and kidney problems, diabetes, and hormonal imbalances may also occur.[1]

Last updated: 12/3/2013

  1. Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. Genetics Home Reference. November 2006; Accessed 10/17/2011.