Hereditary Exostoses, Multiple

National Organization for Rare Disorders, Inc.

It is possible that the main title of the report Hereditary Exostoses, Multiple is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Diaphyseal Aclasis
  • EXT
  • External Chondromatosis Syndrome
  • Multiple Cartilaginous Exostoses
  • Multiple Exostoses
  • Multiple Exostoses Syndrome
  • Multiple Osteochondromatosis

Disorder Subdivisions

  • None

General Discussion

Hereditary multiple exostoses (HME) is a rare genetic disorder characterized by multiple bony growths or tumors (exostoses), often on the growing end (metaphysis) of the long bones of the legs, arms, and digits. These bony growths are covered by cartilage and usually continue to grow until shortly after puberty. Exostoses may lead to bone deformities, skeletal abnormalities, short stature, nerve compression and reduced range of motion. Hereditary multiple exostoses is inherited as an autosomal dominant genetic condition and is associated with abnormalities (mutations) in the EXT1 and EXT 2 genes.


NIH/National Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse
1 AMS Circle
Bethesda, MD 20892-3675
Tel: (301)495-4484
Fax: (301)718-6366
Tel: (877)226-4267
TDD: (301)565-2966

MHE Coalition
6783 York Road, Apt. #104
Parma Heights, OH 44130-4596
Tel: (440)842-8817

MHE and Me- A Support Group for Kids with Multiple Hereditary Exostoses
PO Box 651
Pine Island, NY 10969-0651
Tel: (845)258-6058
Fax: (845)258-6058

MUMS National Parent-to-Parent Network
150 Custer Court
Green Bay, WI 54301-1243
Tel: (920)336-5333
Fax: (920)339-0995
Tel: (877)336-5333

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

MHE Research Foundation
79-77 Street
Brooklyn, NY 11209
Tel: (718)569-0479
Fax: (201)786-1758
Tel: (877)486-1758

For a Complete Report

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc. ® (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see

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