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iduronidase, α-L-
Symbol IDUA
Entrez 3425
HUGO 5391
OMIM 252800
RefSeq NM_000203
UniProt P35475
Other data
EC number
Locus Chr. 4 p16.3

Iduronidase (EC, L-iduronidase, alpha-L-iduronidase) is an enzyme with the system name glycosaminoglycan alpha-L-iduronohydrolase.[1][2][3] This enzyme catalyses the hydrolysis of unsulfated alpha-L-iduronosidic linkages in dermatan sulfate.

It is involved in the degeneration of glycosaminoglycans such as dermatan sulfate and heparan sulfate. It is found in the lysosomes of cells.


A deficiency in the IDUA protein isassociated with mucopolysaccharidoses (MPS). MPS, a type of lysosomal storage disease, is typed I through VII. Type I is known as Hurler syndrome and type I,S is known as Scheie syndrome, which has a milder prognosis compared to Hurler's. In this syndrome, glycosaminoglycans accumulate in the lysosomes and cause substantial disease in many different tissues of the body. IDUA mutations result in the MPS 1 phenotype, which is inherited in an autosomal recessive fashion.[4] The defective alpha-L-iduronidase results in an accumulation of heparan and dermatan sulfate within phagocytes, endothelium, smooth muscle cells, neurons, and fibroblasts. Under electron microscopy these structures present as laminated structures called Zebra bodies.

Prenatal diagnosis of this enzyme deficiency is possible.


  1. ^ Matalon, R., Cifonelli, J.A. and Dorfman, A. (1971). "L-Iduronidase in cultured human fibroblasts and liver". Biochem. Biophys. Res. Commun. 42: 340–345. doi:10.1016/0006-291x(71)90108-2. PMID 4993544. 
  2. ^ Rome, L.H., Garvin, A.J. and Neufeld, E.F. (1978). "Human kidney α-L-iduronidase: purification and characterization". Arch. Biochem. Biophys. 189: 344–353. doi:10.1016/0003-9861(78)90221-7. PMID 30407. 
  3. ^ Srivastava, R.M., Hudson, N., Seymour, F.R. and Weissman, B. (1978). "Preparation of (aryl α-L-idopyranosid)uronic acids". Carbohydr. Res. 60: 315–326. doi:10.1016/s0008-6215(78)80038-x. 
  4. ^ Scott, HS; Nelson, PV; Litjens, T; Hopwood, JJ; Morris, CP (September 1993). "Multiple polymorphisms within the alpha-L-iduronidase gene (IDUA): implications for a role in modification of MPS-I disease phenotype.". Human Molecular Genetics 9: 1471-1473. doi:10.1093/hmg/2.9.1471. PMID 8242073. 

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