Hereditary Multiple Osteochondromas

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Hereditary Multiple Osteochondromas is not the name you expected.

Disorder Subdivisions

  • None

General Discussion


Hereditary multiple osteochondromas (HMO) is a rare genetic disorder characterized by multiple benign (noncancerous) bone tumors that are covered by cartilage (osteochondromas), often on the growing end (metaphysis) of the long bones of the legs, arms, and digits. These osteochondromas usually continue to grow until shortly after puberty and may lead to bone deformities, skeletal abnormalities, short stature, nerve compression and reduced range of motion. Hereditary multiple osteochondromas is inherited as an autosomal dominant genetic condition and is associated with abnormalities (mutations) in the EXT1or EXT2 gene.


Hereditary multiple osteochondromas was formerly called hereditary multiple exostoses.

Supporting Organizations

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

MHE Coalition

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

MHE Research Foundation

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

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

NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases

Information Clearinghouse
One AMS Circle
Bethesda, MD 20892-3675
Tel: (301)495-4484
Fax: (301)718-6366
Tel: (877)226-4267

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  9/19/2012
Copyright  2012 National Organization for Rare Disorders, Inc.