|Multiple Hereditary Exostoses
| Multiple Hereditary Exostoses ("MHE") is a disorder when benign cartilage-capped bone tumors (exostoses) grow outward from the area of the growth plate of long bones or from the surface of flat bones. MHE is known by many different names, including: Multiple Cartilaginous Exostoses, Hereditary Multiple Exostoses, Osteochondromatosis, Hereditary Multiple Osteochondromata, Diaphyseal Aclasis, and more. Exostoses are either sessile or pedunculated. The sessile tumors have a broad-based attachment to the cortex of the bone, while the pedunculated ones have a pedicle arising from the cortex and are usually directed away from the growth plate. According to Wheeless' Textbook of Orthopadeics, more than 40% of people who have MHE have a shortened stature, 50% will have a forearm deformity, 45% will have an ankle deformity, and 20% will have a knee deformity. Hand and wrist deformities are also common, and so are limb-length discrepancies.
MHE is transmitted in an autosomal dominant manner, which means if one parent has it, there is a 50% chance that each of their offspring will inherit the disorder. 10% of cases of MHE are the result of a spontaneous mutation.
The symptoms of MHE are bony growths, which are diagnosed by physical examination and X-ray. Sometimes bone scans and MRI's are used. Most people are diagnosed by the age of three. In addition to shortened stature, bone deformities, and limb length discrepancies, the tumors can cause many other problems. They can compress or stretch peripheral nerves, causing pain and sensory and motor difficulties. They can block motion in adjoining joints. They can irritate overlying tendons and muscles, causing pain and loss of motion. Many people with MHE suffer from severe fatigue. Sometimes exostoses growing on ribs can cause breathing difficulties, and in rare cases, pelvic exostoses can cause urinary or intestinal obstruction. The most serious complication of MHE is that an exostosis can go through a malignant degeneration and become a chondrosarcoma.
Surgery, pain management, physical and occupational therapies are the only treatments used to alleviate the symptoms of this disorder. There are many types of surgeries. They include the removal of a tumor that is causing a problem (interfering with growth, pressing on a nerve, etc.), stapling the growth plate in wrists, knees, or ankles to help stop the limb from bowing, or lengthening of an arm or leg using something called a fixator. However, surgery itself can lead to complications, including staph infection, nerve palsy, and reflex sympathetic dystrophy syndrome ("RSD"), a very painful nerve disorder.
Sadly there is no cure for MHE but many scientists are looking for one. After one of my surgeries, a 3" x 4" tumor that was removed was sent to a laboratory in Texas to help the research that is going on.
Genetic testing is only available on a research basis, and will probably not be available for some time.
The genes that cause this disorder are EXT1 and EXT2. Some scientists have suggested that EXT3 (on chromosome 19p) is also involved but that has not yet been proved. EXT1 is located on the 8q24.1 chromosome and the EXT2 is located on the 11p11-p12 chromosome. So far, 49 mutations have been found in EXT 1, and 25 mutations in EXT2. Scientists believe that the EXT genes may be tumor suppressor genes.
The life of a person with Multiple Hereditary Exostoses is affected greatly because a simple task such as walking or even sitting can cause very severe pain because tumors can press on muscles, tendons, other bones, and nerves, and when that happens it hurts very much. Some people have deformities such as short forearms and have problems doing things like putting on their socks and their shoes. Also MHE causes fatiguing or tiredness and even doing something like walking into class might tire them out. Range of motion is impaired, because the tumors might grow near joints, making movement difficult and painful. Also a simple thing might hurt a person with MHE such as being tapped on the shoulder because when tumors are touched it hurts. People with MHE also might have to use special equipment to help them, such as pencil grips to help their fingers when they are writing or a seat cushion to relieve pressure from the hips, which can be affected. Some people can't write at all and need to use tape recorders or voice recognition softwear to help them. It can be very hard for people with MHE to sleep, because they are lying on painful tumors and can't get comfortable, so they try all kinds of things, like water beds, feather beds, piles of quilts and blankets. Sometimes a wheelchair is needed because some people have MHE so bad that they can't even walk. MHE is not a terminal disease but the tumors can be come cancerous. That means that people with MHE have to make sure to always get check ups, especially grown-ups who are having a lot of pain in a tumor suddenly, or a tumor seems to be growing very fast. Chondrosarcoma can usually be cured by surgical removal when it is found in early stages.
People with this disease also have amazing spirit. In spite of all the pain and surgeries and problems, they find the strength to live their lives in the best way they can.
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