Multiple Exostoses, Hereditary

  • Wim Wuyts
  • Filip Vanhoenacker
  • Wim Van Hul
Reference work entry


Multiple osteochondroma; Multiple cartilaginous exostoses; Diaphyseal aclasis

Definition and Characteristics

Autosomal dominant bone disorder characterized by bony outgrowths (osteochondroma) mainly located at the juxtaepyphyseal parts of the long bones [1]. Number, size, site and shape of the osteochondroma can vary greatly between patients. Pressure of the osteochondromas on neighboring tissues and organs causes pain, reduced mobility and compression of nerves, muscles and blood vessels. Deformity of legs, forearms (resembling Madelung deformity) and shorter stature are frequently observed in osteochondroma patients. In 0.5–2% of these patients chondrosarcoma development is observed.


The prevalence of hereditary multiple exostoses is estimated to be one in 50,000 world wide.


EXT1 localized on chromosome 8q24 [2] and EXT2 localized on chromosome 11p11.2. [3,4].

Molecular and Systemic Pathophysiology

EXT1 and EXT2 genes encode glycosyltransferases which form a...

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  1. 1.
    Schmale et al. (1994) The natural history of hereditary multiple exostoses. J Bone Joint Surg 76:986–992PubMedGoogle Scholar
  2. 2.
    Ahn J et al. (1995) Cloning of the putative tumour suppressor gene for hereditary multiple exostoses (EXT1). Nat Genet 11:137–143PubMedGoogle Scholar
  3. 3.
    Wuyts W et al. (1996) Positional cloning of a gene involved in hereditary multiple exostoses. Hum Mol Genet 5:1547–1557PubMedGoogle Scholar
  4. 4.
    Stickens D et al. (1996) The EXT2 multiple exostoses gene defines a family of putative tumour suppressor genes. Nat Genet 14:25–32PubMedGoogle Scholar
  5. 5.
    Lind T et al. (1998) The putative tumor suppressors EXT1 and EXT2 are glycosyltranserases required for the biosynthesis of heparan sulfate. J Biol Chem 273:26265–26268PubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Berlin Heidelberg 2009

Authors and Affiliations

  • Wim Wuyts
    • 1
  • Filip Vanhoenacker
    • 1
  • Wim Van Hul
    • 1
  1. 1.Department of Medical GeneticsUniversity of AntwerpAntwerpBelgium