Hereditary Multiple Exostoses
General Description
The following is a general description of Hereditary Multiple Exostoses. It is not meant for diagnostic or medical purposes but to provide the general public with an basic understanding of this syndrome.
Introduction
Hereditary Multiple Exostoses is a disorder affecting bone growth. It is inherited in an autosomal dominant fashion. This means that there is a 50% chance of an affected parent passing the trait to their offspring and that the sex of the offspring or the affected parent probably has no bearing on the frequency of transmission. An exostosis (singular) can be described as a bony growth (or bump) that develops off of a "normal" bone. Exostoses (plural), can develop off of almost any bone, with the possible exception of the bones of the face and head. The number and size of these exostoses (or bony growths) can be somewhat variable among affected individuals. This means that some individuals may have many large exostoses, whereas other individuals may have only a few small ones. The factors that result in these differences are not yet understood.
Complications
Sometimes, the exostoses are minor (almost unnoticeable) and have no affect on the affected individuals lifestyle. On the other hand, they can result in moderate to severe problems. These include short stature as well as, bowed arms and legs. In addition, the exostoses can sometimes be positioned such that they impair normal movement of the joints or pinch nerves and tendons. Generally these growths are not malignant and as an individual becomes an adult and stops getting taller, the exostoses also stop growing. However, in rare cases the exostoses can develop into a malignant tumor. This most frequently happens to adults in their 20's to 50's.
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This page last updated 1/30/97.