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IDS gene

iduronate 2-sulfatase

Normal Function

The IDS gene provides instructions for producing an enzyme called iduronate 2-sulfatase (I2S), which is essential for the breakdown of large sugar molecules called glycosaminoglycans (GAGs). Specifically, I2S removes a chemical group known as a sulfate from a molecule called sulfated alpha-L-iduronic acid, which is present in two GAGs called heparan sulfate and dermatan sulfate. I2S is located in lysosomes, which are compartments within cells that digest and recycle different types of molecules.

Health Conditions Related to Genetic Changes

Mucopolysaccharidosis type II

Hundreds of variants (also called mutations) in the IDS gene have been found to cause mucopolysaccharidosis type II (MPS II). Variants that change one DNA building block (nucleotide) are the most common. All the variants that cause MPS II reduce or completely eliminate the function of the I2S enzyme in cells.

There are two types of MPS II: the neuropathic form, which is more severe, and the non-neuropathic form, which is less severe. It is difficult to tell which variants cause each form of the disorder. However, variants that remove large pieces of the gene or rearrange the genetic material, completely eliminating I2S enzyme function, often cause the neuropathic form of the disorder.

Lack of I2S enzyme activity leads to the accumulation of heparan sulfate and dermatan sulfate within lysosomes in cells. The buildup of these GAGs increases the size of the lysosomes, which is why many tissues and organs are enlarged in people with MPS II. Researchers believe that the accumulated GAGs may also interfere with the functions of other proteins inside the lysosomes and disrupt the movement of molecules inside the cell. In addition, buildup in lysosomes may trigger the release of molecules called cytokines that stimulate inflammation and may contribute to the progression of MPS II.

More About This Health Condition

Other Names for This Gene

  • iduronate 2-sulfatase (Hunter syndrome)
  • iduronate-2-sulfatase

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Azambuja AS, Pimentel-Vera LN, Gonzalez EA, Poletto E, Pinheiro CV, Matte U, Giugliani R, Baldo G. Evidence for inflammasome activation in the brain of mucopolysaccharidosis type II mice. Metab Brain Dis. 2020 Oct;35(7):1231-1236. doi: 10.1007/s11011-020-00592-5. Epub 2020 Jul 4. Citation on PubMed
  • Clarke LA. The mucopolysaccharidoses: a success of molecular medicine. Expert Rev Mol Med. 2008 Jan 18;10:e1. doi: 10.1017/S1462399408000550. Citation on PubMed
  • Jacques CE, Donida B, Mescka CP, Rodrigues DG, Marchetti DP, Bitencourt FH, Burin MG, de Souza CF, Giugliani R, Vargas CR. Oxidative and nitrative stress and pro-inflammatory cytokines in Mucopolysaccharidosis type II patients: effect of long-term enzyme replacement therapy and relation with glycosaminoglycan accumulation. Biochim Biophys Acta. 2016 Sep;1862(9):1608-16. doi: 10.1016/j.bbadis.2016.05.021. Epub 2016 May 29. Citation on PubMed
  • Martin R, Beck M, Eng C, Giugliani R, Harmatz P, Munoz V, Muenzer J. Recognition and diagnosis of mucopolysaccharidosis II (Hunter syndrome). Pediatrics. 2008 Feb;121(2):e377-86. doi: 10.1542/peds.2007-1350. Citation on PubMed
  • Scarpa M. Mucopolysaccharidosis Type II. 2007 Nov 6 [updated 2024 Apr 11]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from Citation on PubMed
  • Trowbridge JM, Gallo RL. Dermatan sulfate: new functions from an old glycosaminoglycan. Glycobiology. 2002 Sep;12(9):117R-25R. doi: 10.1093/glycob/cwf066. Citation on PubMed
  • Wraith JE, Scarpa M, Beck M, Bodamer OA, De Meirleir L, Guffon N, Meldgaard Lund A, Malm G, Van der Ploeg AT, Zeman J. Mucopolysaccharidosis type II (Hunter syndrome): a clinical review and recommendations for treatment in the era of enzyme replacement therapy. Eur J Pediatr. 2008 Mar;167(3):267-77. doi: 10.1007/s00431-007-0635-4. Epub 2007 Nov 23. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.