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Diseases

Genetic and Rare Diseases Information Center (GARD)

Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes


Other Names for this Disease
  • MELAS
  • MELAS syndrome
  • Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes
  • Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Symptoms

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What are the signs and symptoms of Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes?

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

The Human Phenotype Ontology provides the following list of signs and symptoms for Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.

Signs and Symptoms Approximate number of patients (when available)
obsolete Macrocephaly due to hydrocephalusis_obsolete: true 50%
Reticulated skin pigmentation 7.5%

Last updated: 8/1/2015

The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.

The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.

Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.


References
  1. Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. Genetics Home Reference. November 2006; http://ghr.nlm.nih.gov/condition/mitochondrial-encephalomyopathy-lactic-acidosis-and-stroke-like-episodes. Accessed 10/17/2011.


Other Names for this Disease
  • MELAS
  • MELAS syndrome
  • Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes
  • Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.