Skip to main content

Diseases Studied

The Rare Diseases Clinical Research Network is an NIH-funded research network of 20 active consortia or research groups working to advance treatment for diseases that are rare. Use the search tools on this page to find the diseases we currently study. You can reach out to the indicated consortia or research groups for more information on those diseases and studies underway.

This network focuses on clinical research and does not generally support clinical care outside of research activities. To learn about other rare diseases, please visit the Genetic and Rare Diseases Information Center (GARD), which is an NIH program that helps the public find reliable information about rare and genetic diseases. Their staff are specialists. Contact them at 1-888-205-2311 or email

All Diseases > Mitochondrial Encephalomyopathy Lactic Acidosis with Stroke-Like Episodes

Mitochondrial Encephalomyopathy Lactic Acidosis with Stroke-Like Episodes (MELAS)

Alternative Names: MELAS Syndrome; Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-Like Episodes

Disease Category: Mitochondrial Disorders

A rare, inherited disorder of the nerves and muscles caused by mutations affecting the mitochondria (specialized cell structures that produce energy). The main manifestations are stroke-like episodes causing neurological problems such as hemiparesis (muscle weakness on one side of the body) or hemianopsia (loss of vision on the left or right side), seizures, encephalopathy (brain disease), lactic acidosis (high blood lactate levels). Other symptoms and signs include: hearing loss, severe recurrent headaches, altered consciousness, intellectual disability, muscle and abdominal pain, loss of appetite, vomiting, fatigue, myoclonus (muscle jerking), ataxia (lack of coordination), diabetes, hormonal imbalance, heart problems, and kidney problems.

Research groups studying this disease

Mitochondrial Disorders
NAMDC logo

North American Mitochondrial Disease Consortium (NAMDC)

Improves quality of life for people affected by mitochondrial disease through education, outreach, advocacy, and clinical research initiatives.

Promotes research and education for the diagnosis, treatment, and cure of mitochondrial disorders while providing support to those affected.