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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed December 2008

What is the official name of the IDS gene?

The official name of this gene is “iduronate 2-sulfatase.”

IDS is the gene's official symbol. The IDS gene is also known by other names, listed below.

What is the normal function of the IDS gene?

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, compartments within cells that digest and recycle different types of molecules.

How are changes in the IDS gene related to health conditions?

mucopolysaccharidosis type II - caused by mutations in the IDS gene

More than 300 mutations in the IDS gene have been found to cause mucopolysaccharidosis type II (MPS II). Mutations that change one DNA building block (nucleotide) are the most common. All mutations that cause MPS II reduce or completely eliminate the function of I2S. It usually cannot be determined whether a certain mutation will cause severe or mild MPS II; however, mutations that result in the complete absence of I2S cause the more severe form of the disorder.

Lack of I2S enzyme activity leads to the accumulation of heparan sulfate and dermatan sulfate within cells, specifically inside the lysosomes. The buildup of these GAGs increases the size of the lysosomes, which is why many tissues and organs are enlarged in 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.

Where is the IDS gene located?

Cytogenetic Location: Xq28

Molecular Location on the X chromosome: base pairs 149,478,764 to 149,505,354

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The IDS gene is located on the long (q) arm of the X chromosome at position 28.

The IDS gene is located on the long (q) arm of the X chromosome at position 28.

More precisely, the IDS gene is located from base pair 149,478,764 to base pair 149,505,354 on the X chromosome.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about IDS?

You and your healthcare professional may find the following resources about IDS helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the IDS gene or gene products?

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

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding IDS?

breakdown ; cell ; DNA ; enzyme ; gene ; heparan sulfate ; molecule ; mutation ; nucleotide ; sulfate ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Clarke LA. The mucopolysaccharidoses: a success of molecular medicine. Expert Rev Mol Med. 2008 Jan 18;10:e1. doi: 10.1017/S1462399408000550. Review. (
  • Gene Review: Mucopolysaccharidosis Type II (
  • Martin R, Beck M, Eng C, Giugliani R, Harmatz P, Muñoz V, Muenzer J. Recognition and diagnosis of mucopolysaccharidosis II (Hunter syndrome). Pediatrics. 2008 Feb;121(2):e377-86. doi: 10.1542/peds.2007-1350. Review. (
  • NCBI Gene (
  • Trowbridge JM, Gallo RL. Dermatan sulfate: new functions from an old glycosaminoglycan. Glycobiology. 2002 Sep;12(9):117R-25R. Review. (
  • 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. Epub 2007 Nov 23. Review. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: December 2008
Published: February 8, 2016