Multiple Hereditary Exostoses


This disease causes bones to grow benign bone tumors. The tumors normally grow on long flat bones.

Some patients have uneven limbs because the tumors do not grow evenly, disturbing the amount of nourishment in different parts of the body.

Gene Mutation

Mutations in the EXT1 and EXT2 genes cause MHE. They code the instructions to make exostosin-1 and exostosin-2, which later bind together and form a complex structure in the golgi apparatus, thus damaging haparan sulfate. Without correct cumbers of haparan sulfate, MHE occurs. It is not known why.

Chemical Composition of haparan sulfate

10% of cases of MHE are not caused by the EXT genes. It is not known what causes these cases.


This is an autosomal inheritance pattern

There are about 1 in 50,000 people that have this disease, thus making it very rare.

Gender does not affect MHE, but there are more boys than female with MHE. about 75% of cases are male while 25% are female.

More Examples

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