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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 > Sensory Ataxia Neuropathy Dysarthria and Ophthalmoplegia

Sensory Ataxia Neuropathy Dysarthria and Ophthalmoplegia (SANDO)

Alternative Names: Sensory Ataxia Neuropathy Syndrome, SANDO, Sensory Ataxic Neuropathy-Dysarthria-Ophthalmoparesis Syndrome

Disease Category: Mitochondrial Disorders

A rare, inherited disorder caused by depletion (fewer) or deletions (fragmented) DNA within mitochondria (specialized cell structures that produce energy) in skeletal muscles and limb nerves. It is characterized by abnormal sensations such as tingling, numbness, or pain in the arms and legs, ataxia (lack of coordination), generalized muscle weakness, seizures, ptosis (eyelid drooping), ophthalmoplegia (eye muscle weakness), dysarthria (speech impairment due to muscle weakness), vision loss, migraines, liver disease, cognitive impairment, depression, and myoclonus (muscle twitches).

Research groups studying this disease

Mitochondrial Disorders
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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.