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Exostoses, Multiple Cartilaginous also refered to as (MHE) Multiple Hereditary Exostoses also often referred to as Hereditary Multiple Exostoses (HME) Multiple Osteochondromas (MO) is the preferred term used by the World Health Organization.

MHE / MO / HME is a genetic Disorders of bone in which benign cartilage-capped bone tumors that grow outward from the metaphyses of long bones, growth plates of long bones or from the surface of flat bones throughout the body.

These Exostoses / Osteochondromas can cause numerous problems, including: compression of peripheral nerves or blood vessels; irritation of tendons and muscles resulting in pain and loss of motion; skeletal deformity; short stature; limb length discrepancy; chronic pain and fatigue; mobility issues; early onset arthritis; and an increased risk of developing chondro- sarcoma, reported risk of 2%-5% over life time.

It is not uncommon for MHE / MO / HME patients to undergo numerous surgical procedures throughout their lives to remove painful or deforming Exostoses / Osteochondromas and or to correct limb length discrepancies and improve range of motion.

Surgery, physical therapy and pain management are currently the only options available to MHE / MO / HME patients, but their success varies from patient to patient and many struggle with pain, fatigue and mobility problems throughout their lives.

MHE / MO / HME is an autosomal dominant hereditary disorder. This means that a patient with MHE / MO / MHE has a 50% chance of transmitting this disorder to his / her children.

This is equal for both male and female patients. Normally this disorder does not skip a generation.

Most individuals with MHE / MO / HME have a parent who also has the condition, however, approximately 10% -20% of individuals with MHE / MO / HME have the condition as a result of a spontaneous mutation are thus the first person in their family to be affected.

There are two known Genes that cause this disease EXT1 located on chromosome 8q23-q24 and EXT2 located on chromosome 11p11-p12. Approximately 60 to 70% are located EXT1 gene and 20 to 30% are located EXT2 mutation. Genetic Testing, Prenatal Diagnosis and Preimplantion Genetic Diagnosis "PDG" are available. Please check the Genetics section for more detailed information.

The major defect in the EXT genes that cause MHE is the lack of Heparan Sulphate.

The MHE Research Foundation, includes Comprehensive information on Research being conducted and MHE Conferences, Orthopeadics, Genetics and Chronic Pain that can be associated with this disorder . For more information on Hereditary Multiple Exostoses please vist the MHE Research Foundation's Website: http://www.MHEResearchFoundation.org