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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 > Hurler syndrome

Hurler syndrome (MPS I)

Alternative Names: Mucopolysaccharidosis Type I-H (MPS IH); Alpha-L-Iduronidase Deficiency (IDUA Deficiency)

Disease Category: Lysosomal Diseases

A rare, inherited lysosomal disorder, caused by a missing or abnormal enzyme that cannot break down glycosaminoglycans (GAGs, complex sugar molecules with amino groups that are critical components of connective tissues). There is significant overlap of symptoms between three syndromes (this form, Scheie, and the combined form). Symptoms affect the heart, eyes, ears, liver, spleen, and respiratory, neurological, and musculoskeletal systems. Hurler syndrome is the severe form of mucopolysaccharidosis type I (MPS I).

Research groups studying this disease

Lysosomal Diseases
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Lysosomal Disease Network (LDN)