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


Reviewed October 2012

What is the official name of the EXT2 gene?

The official name of this gene is “exostosin glycosyltransferase 2.”

EXT2 is the gene's official symbol. The EXT2 gene is also known by other names, listed below.

What is the normal function of the EXT2 gene?

The EXT2 gene provides instructions for producing a protein called exostosin-2. This protein is found in a cell structure called the Golgi apparatus, which modifies newly produced enzymes and other proteins. In the Golgi apparatus, exostosin-2 attaches (binds) to another protein, exostosin-1, to form a complex that modifies a protein called heparan sulfate so it can be used in the body. Heparan sulfate is involved in regulating a variety of body processes including the formation of blood vessels (angiogenesis) and blood clotting. It also has a role in the spreading (metastasis) of cancer cells.

How are changes in the EXT2 gene related to health conditions?

hereditary multiple exostoses - caused by mutations in the EXT2 gene

More than 90 mutations in the EXT2 gene have been identified in people with hereditary multiple exostoses type 2, a condition in which people develop multiple benign (noncancerous) bone tumors called exostoses. Most of these mutations prevent any functional exostosin-2 protein from being made, and are called "loss-of-function" mutations. The loss of exostosin-2 protein function prevents it from forming a complex with the exostosin-1 protein and modifying heparan sulfate. It is unclear how this impairment leads to the signs and symptoms of hereditary multiple exostoses.

Potocki-Shaffer syndrome - caused by mutations in the EXT2 gene

A mutation resulting in the deletion of the EXT2 gene causes a condition called Potocki-Shaffer syndrome. People with this condition have multiple exostoses (described above) and enlarged openings in two bones that make up much of the top and sides of the skull (enlarged parietal foramina). Other signs and symptoms seen in some people with Potocki-Shaffer syndrome include intellectual disability, developmental delay, distinctive facial features, vision problems, and defects in the heart, kidneys, and urinary tract.

Potocki-Shaffer syndrome (sometimes referred to as proximal 11p deletion syndrome) is caused by a deletion of genetic material from the short (p) arm of chromosome 11. In people with this condition, a loss of the EXT2 gene within this region is responsible for multiple exostoses. The deletion likely leads to a reduction of exostosin-2 protein and the inability to process heparan sulfate correctly. Although heparan sulfate is involved in many body processes, it is unclear how the lack of this protein causes multiple exostoses. The loss of another gene, ALX4, in the same region of chromosome 11 underlies the defects in skull development. The loss of additional genes in the deleted region likely contributes to the other features of Potocki-Shaffer syndrome.

Where is the EXT2 gene located?

Cytogenetic Location: 11p12-p11

Molecular Location on chromosome 11: base pairs 44,095,549 to 44,245,430

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

The EXT2 gene is located on the short (p) arm of chromosome 11 between positions 12 and 11.

The EXT2 gene is located on the short (p) arm of chromosome 11 between positions 12 and 11.

More precisely, the EXT2 gene is located from base pair 44,095,549 to base pair 44,245,430 on chromosome 11.

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

Where can I find additional information about EXT2?

You and your healthcare professional may find the following resources about EXT2 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 EXT2 gene or gene products?

  • exostoses (multiple) 2
  • exostosin 2
  • Glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-alpha-N- acetylglucosaminyltransferase
  • N-acetylglucosaminyl-proteoglycan 4-beta-glucuronosyltransferase
  • SOTV

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

What glossary definitions help with understanding EXT2?

angiogenesis ; benign ; blood clotting ; cancer ; cell ; chromosome ; clotting ; deletion ; developmental delay ; disability ; exostoses ; gene ; Golgi apparatus ; heparan sulfate ; hereditary ; metastasis ; mutation ; protein ; proteoglycan ; proximal ; sulfate ; syndrome

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


  • Francannet C, Cohen-Tanugi A, Le Merrer M, Munnich A, Bonaventure J, Legeai-Mallet L. Genotype-phenotype correlation in hereditary multiple exostoses. J Med Genet. 2001 Jul;38(7):430-4. (
  • Hall CR, Wu Y, Shaffer LG, Hecht JT. Familial case of Potocki-Shaffer syndrome associated with microdeletion of EXT2 and ALX4. Clin Genet. 2001 Nov;60(5):356-9. (
  • Ligon AH, Potocki L, Shaffer LG, Stickens D, Evans GA. Gene for multiple exostoses (EXT2) maps to 11(p11.2p12) and is deleted in patients with a contiguous gene syndrome. Am J Med Genet. 1998 Feb 17;75(5):538-40. (
  • Lonie L, Porter DE, Fraser M, Cole T, Wise C, Yates L, Wakeling E, Blair E, Morava E, Monaco AP, Ragoussis J. Determination of the mutation spectrum of the EXT1/EXT2 genes in British Caucasian patients with multiple osteochondromas, and exclusion of six candidate genes in EXT negative cases. Hum Mutat. 2006 Nov;27(11):1160. (
  • McCormick C, Duncan G, Goutsos KT, Tufaro F. The putative tumor suppressors EXT1 and EXT2 form a stable complex that accumulates in the Golgi apparatus and catalyzes the synthesis of heparan sulfate. Proc Natl Acad Sci U S A. 2000 Jan 18;97(2):668-73. (
  • NCBI Gene (
  • Romeike BF, Wuyts W. Proximal chromosome 11p contiguous gene deletion syndrome phenotype: case report and review of the literature. Clin Neuropathol. 2007 Jan-Feb;26(1):1-11. Review. (
  • Wakui K, Gregato G, Ballif BC, Glotzbach CD, Bailey KA, Kuo PL, Sue WC, Sheffield LJ, Irons M, Gomez EG, Hecht JT, Potocki L, Shaffer LG. Construction of a natural panel of 11p11.2 deletions and further delineation of the critical region involved in Potocki-Shaffer syndrome. Eur J Hum Genet. 2005 May;13(5):528-40. (
  • Wuyts W, Van Hul W, De Boulle K, Hendrickx J, Bakker E, Vanhoenacker F, Mollica F, Lüdecke HJ, Sayli BS, Pazzaglia UE, Mortier G, Hamel B, Conrad EU, Matsushita M, Raskind WH, Willems PJ. Mutations in the EXT1 and EXT2 genes in hereditary multiple exostoses. Am J Hum Genet. 1998 Feb;62(2):346-54. (
  • Wuyts W, Waeber G, Meinecke P, Schüler H, Goecke TO, Van Hul W, Bartsch O. Proximal 11p deletion syndrome (P11pDS): additional evaluation of the clinical and molecular aspects. Eur J Hum Genet. 2004 May;12(5):400-6. 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: October 2012
Published: February 8, 2016