Hereditary Multiple Osteochondromas: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Hereditary Multiple Osteochondromas?
A primary care doctor is often the first to notice the condition. An orthopedic surgeon usually manages the growths, and a geneticist may help with testing and family counseling. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What it is
Hereditary multiple osteochondromas is a genetic condition passed down in families. It causes noncancerous growths called osteochondromas, made of bone and cartilage, to form on bones, usually near the ends of long bones during childhood.
Symptoms
Many people have few or no problems. Symptoms can include hard bumps near a joint, uneven bone growth leading to shorter arms or legs, and pressure on nerves or tendons causing pain, numbness, or joint stiffness. In rare cases, a growth can turn into a cancer called chondrosarcoma, usually in adulthood.
Causes and who gets it
It is caused by mutations in the EXT1 or EXT2 genes, which normally keep bone growth under control. A child has a one in two chance of getting it if one parent has it. It affects about one in fifty thousand people.
How doctors diagnose it
Doctors often find the growths during an exam or on an X-ray. A genetic blood test can confirm the diagnosis by finding a change in the EXT1 or EXT2 gene.
Treatment
Growths causing no pain need only regular checkups. Painful growths can be removed by a surgeon, who can also correct problems such as a difference in leg length.
When to see a doctor
See a doctor if you or your child has a hard lump near a bone or joint, especially if it is growing, painful, or causing numbness, weakness, or trouble moving a limb.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance; a concierge doctor usually charges more and often works alongside insurance. Either can handle exams, testing, and monitoring, referring to specialists when needed.
Common questions
Are the growths cancerous?
No, osteochondromas are noncancerous growths. In a small number of people, one growth can turn into a cancer called chondrosarcoma. This is why regular follow-up matters.
Will my children get this condition?
If a parent has the condition, each child has a one in two chance of inheriting it. A genetic counselor can help families understand testing options.
Do the growths need to be removed?
Not always. Many growths cause no problems and are simply watched over time. Painful ones can be removed with surgery.
Do the growths keep growing in adults?
Most growths stop growing once a person finishes growing, usually in the late teens or early twenties. A growth that keeps growing in an adult should be checked by a doctor.
Sources
- NIH Genetic and Rare Diseases Information Center - Multiple congenital exostosis
- MedlinePlus Genetics - Hereditary multiple osteochondromas
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
