Hereditary multiple exostoses Hereditary Multiple Exostoses ( HME ) is a medical condition whereby multiple exostoses ( bony spurs or lumps , also known as osteochondromas ) develop on the bones of a child . Generally , when a person with HME reaches maturity , and their bones stop growing , the exostoses also stop growing . It is estimated to occur in 1 in 50 , 000 people . A person with HME is more likely to develop a form of bone cancer called chrondosarcoma as an adult . It is an autosomal dominant disorder . ( MHE ) Multiple Hereditary Exostoses are also often referred to as Hereditary Multiple Exostoses ( HME ) Multiple Osteochondromas ( MO ) is the preferred term used by the World Health Organization . MO is a genetic bone disorder in which benign cartilage-capped bone tumors grow outward from the metaphyses of long bones , growth plates of long bones or from the surface of flat bones throughout the body . If necessary , the exostoses can be removed by surgery . 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 , with a reported risk of 2%-5% over life time . It is not uncommon for MO patients to undergo numerous surgical procedures throughout their lives to remove painful or deforming Exostoses / Osteochondromas , correct limb length discrepancies or improve range of motion . Surgery , physical therapy and pain management are currently the only options available to MO patients , but success varies from patient to patient and many struggle with pain , fatigue and mobility problems throughout their lives . MO is an autosomal dominant hereditary disorder . This means that a patient with MO has a 50% chance of transmitting this disorder to his or her children . This is equal for both male and female patients . Normally this disorder does not skip a generation . Most individuals with MO have a parent who also has the condition , however , approximately 10% -20% of individuals with MO have the condition as a result of a spontaneous mutation and 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 in the EXT1 gene and 20 to 30% are located in the EXT2 mutation . Genetic Testing , Prenatal Diagnosis and Preimplantion Genetic Diagnosis `` PDG '' are all available . 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 , MHE Conferences , Orthopeadics , Genetics and Chronic Pain associated with this disorder . External links Medcyclopaedia Online Mendelian Inheritance in Man ( OMIM ) ( HME Type I ) Online Mendelian Inheritance in Man ( OMIM ) ( HME Type II ) For more information on Hereditary Multiple Exostoses please vist the MHE Research Foundation 's Website : http : //www.MHEResearchFoundation.org  This genetic disorder article is a stub . You can help Wikipedia by expanding it . Categories : Genetic disorders | Genetic disorder stubs In other languages : Français | Nederlands 