Hereditary Multiple Exostoses

Hereditary multiple exostoses (HME), now known as hereditary multiple osteochondromas (HMO), is a genetic disorder which promotes the growth of multiple benign (noncancerous) osteochondromas (bone tumours). The tumours can appear at the end of long bones and on flat bones such the hip and the shoulder blade.
Osteochondromas (bone tumours) are made of cartilage and bone, and develop as a mass that grows away from the bone. Your child may inherit the gene from you but the tumours are not present at birth. Individuals affected by this disorder usually develop multiple exostoses by the age of 12. Once the child has reached their maximum height, the tumour stops growing and new tumours may also cease to develop.
It is an extremely rare disorder, occurring in 1 in every 50,000 individuals worldwide.

Symptoms associated with HME depend on the location of the tumours. These include:

  • Pain or numbness due to nerve compressure

  • Shortening or bowing of limps

  • Short stature (shorter than the average height for that age)

  • Visible protruding bony mass

  • Difference in limb lengths

  • Limited mobility​

Bring your child for a consultation from one of our internationally trained doctors at the Children's Hospital at The Aga Khan University Hospital.​
​Your time with your doctor maybe limited, so make sure to prepare for your visit beforehand. Here are some tips to help get y​ou started.​

HME can be diagnosed before birth or after if a child begins to exhibit symptoms.

Diagnosis before birth includes:

Testing DNA taken from the foetus. The DNA can be obtained by:

  • Amniocentesis in which the amniotic fluid surrounding the foetus is extracted using a needle to be tested. This is done after fifteen weeks of pregnancy

  • Chorionic villus sampling (CVS) in which a sample of the chorionic villi is extracted from the placenta for testing. The sample can be removed through the cervix or the abdominal wall. This is done between the eleventh and fourteenth week of pregnancy.

These procedures are used if you already have a child with HME or you or your partner suffer from this disorder. Before carrying out these tests on your foetus, the doctor should know the mutation in the gene responsible for causing HME. Therefore, the affected parent may have to undergo genetic testing (blood test).

Diagnosis after birth includes:

  • X-ray in which a small amount of radiation is used to generate an image of your child’s bones and organs

  • DNA testing. This is done by drawing a blood sample for testing​

The treatment options provided will depend on the symptoms your child is experiencing. These include:

  • Pain medications for painful lesions

  • Surgical excision if the tumour causes disturbance in growth or disability

  • Physical therapy

Your child may have to go numerous surgical procedures for subsequent growth of tumours that cause pains and deformities. They would require your constant support because even with complete removal of the tumour, it can still recur. 

If the tumour is not removed because of lack of symptoms, it must be monitored for there is a slim chance (less than 1%) that can turn cancerous. An adult that notices an extoses undergoing rapid growth or causing pain in a previously painless area should notify a doctor immediately for early detection and treatment.  ​

The Aga Khan University Hospital offers various support services to help with managing or recovering from the disease or condition. These include but are not limited to nutrition, physiotherapy, rehabilitation, specialized clinics and some patient support groups. Your doctor or nurse will advise you accordingly.

The Aga Khan University Hospital offers financial assistance to those who are in need and fulfil the eligibility criteria. For further information, you can contact the Patient Welfare Department. You can find the contact number of the Patient Welfare Department in the ‘Important Numbers’ section on the website homepage.

The financial counselling staff is available during office hours, at the main PBSD (Patient Business Services Department), to answer your financial queries on treatments’ costs and authorize admissions on partial deposit as per hospital policies allow. The financial counsellor in the emergency room is open 24/7. You can find the contact number of the Patient Business Services in the ‘Important Numbers’ section on the website homepage.​

Your doctor and or nurse will give you specific instructions about the prescribed medication. Please ensure that you take or use the prescribed medicine as advised. It can be dangerous to your health if you self-prescribe. Please inform the doctor or nurse beforehand if you have experienced any adverse reactions to any medications in the past. If you experience any symptoms of drug poisoning, overdose or severe reaction please contact the Pharmacy Service at The Aga Khan University Hospital immediately. You can find the contact number of the Pharmacy Services in the ‘Important Numbers’ section on the website homepage

The information provided on our website is for educational purposes and not intended to be a substitute for medical advice, diagnosis or treatment. You should always seek the advice of your doctor or other healthcare professional provider.