What is Hereditary Multiple Exostoses?
Hereditary Multiple Exostoses (HME, EXT, MHE, Diaphyseal Aclasis, Familial Bony Spurs) is usually but not necessarily an inherited condition which can produce bony lumps close to the end of any bone, but particularly those of the limbs. These lumps tend to grow during childhood, causing occasional discomfort. Sometimes a limb may end up shorter, or less straight than normal. These problems sometimes require hospital appointments and surgery. Lumps usually stop growing at the end of childhood. The genetics of Hereditary Multiple Exostoses has recently become clearer. Genes responsible for this condition are now being identified.
Whilst reading our website, please bear in mind that the severity of Hereditary Multiple Exostoses varies from person to person. As a Support Group we are in contact with HME sufferers who have lived long and active lives without serious problems, those who have had severe problems and many in between. Problems you may read about in the personal accounts on the website are not inevitable for everyone, but it can be helpful to be aware of them.
More About HME
The information provided on this site is designed to support, not replace, the relationship that exists between a patient or site visitor and his or her doctor. The medical information is based on minutes taken at the meetings the Group has held at the Nuffield Orthopaedic Centre, Oxford, United Kingdom, since 1997. In particular, the material contained in What is HME? and The Natural History and Treatment of Arm Problems in HME is based on talks given to the Group by orthopaedic surgeons with a particular interest in HME and has been seen and approved by the speakers.
What is HME?
This section summarises what is known about HME at the moment. Start here if this is the first time you have come across the condition. There are five pages:
- What is HME?
- Normal bone growth, what is an exostosis, what is multiple exostoses and how common is it?
- Genetics
- Recent discoveries about the genetics of HME, why only some bones are affected and why genetic studies are important.
- Effects
- How changes in growth rate affect the forearm and lower leg, nerves and tendons and cause pain and discomfort. What you should do if a lump starts growing again or becomes painful.
- Treatment
- Treatment may be for cosmetic reasons, because a lump is blocking movement or pressing on a nerve or tendon, growth is uneven, there is pain or discomfort, or the cartilage has become thickened. Rarely treatment may be needed because malignancy is suspected.
- Other Info
- This page includes an explanation of the terms doctors use, references to scientific papers and links to other HME sites on the Internet.
Arm Problems in HME
Arm problems are common in HME. This section is based on a talk given to the Support Group by Mr Peter Burge FRCS, Consultant Orthopaedic Surgeon and arm specialist. In his talk Mr Burge described the problems that can occur and how they can be treated. He also discussed the recently introduced forearm lengthening procedure.
The Role of the Radiographer in HME
Ever wondered what happens when you have an x-ray? Radiographer Peter Machin explains.
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Which name do you use for this condition?
What's in a name?
When doctors don't understand something, they simply describe it in Greek or Latin. How would you describe HME? Perhaps "lumps on my bones"? Or you might add "inherited from one of my parents"? In fact, that's all these complicated and rather frightening names mean:
- Exostosis
- A lump on a bone, from the Greek words "ex" which means "out of" and "osteon" which means "bone".
- Exostoses
- Lumps (the plural of exostosis is exostoses).
- Multiple Exostoses
- Many lumps.
- Hereditary Multiple Exostoses
- Many lumps, passed on from one of your parents.
- Multiple Hereditary Exostoses
- Same as Hereditary Multiple Exostoses.
- Hereditary Multiple Exostosis
- This name is also used, although it is not really correct since it means "many lump".
- Familial Bony Spurs
- Lumps that run in families (which comes to the same thing).
- Osteochondroma
- A lump of bone and cartilage, from the Greek words "osteon" which means "bone" and "chondros" which means "cartilage" (gristle). Exostoses have a little bit of cartilage at the tip and this is just a more detailed way of describing them.
- Osteochondromata
- Lumps (plural of osteochondroma).
- Multiple Osteochondromata
- Many lumps.
- Osteochondromatosis
- The condition of having lumps.
- Diaphyseal Aclasis
- Another feature of HME, though less noticeable than the lumps. The "diaphysis" is "the bit that grows between" the ends of a bone, that is, the middle part or shaft (as opposed to the "epiphysis" which means "the bit at the end"). "a" means "without" and "clasis" means "breaking". There is disruption of normal modelling, or remodelling of bone.