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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 > Sanfilippo syndrome A

Sanfilippo syndrome A (MPS IIIA)

Alternative Names: Mucopolysaccharide Storage Disease Type III A; Mucopolysaccharidosis Type III A; Sanfilippo Disease, Sanfilippo Syndrome Type A

Disease Category: Lysosomal Diseases

A rare, inherited, lysosomal disorder, caused by a missing or abnormal enzyme that cannot break down heparan sulfate (a complex sugar molecule containing sulfate). This disease is the most severe and rapidly progressive of four types (A, B, C, and D), each caused by different mutated genes. Some symptoms include psychomotor (mental and motor skill) regression, behavioral and sleep problems, hirsutism (excessive hair growth), seizures, unsteady gait, and vision and hearing loss.

Research groups studying this disease

Lysosomal Diseases
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Lysosomal Disease Network (LDN)

Accelerates research to find the first-ever FDA-approved treatment or cure for Sanfilippo syndrome.