Exostoses, Multiple Hereditary

**Definition:** Hereditary disorder transmitted by an autosomal dominant gene and characterized by multiple exostoses (multiple osteochondromas) near the ends of long bones. The genetic abnormality results in a defect in the osteoclastic activity at the metaphyseal ends of the bone during the remodeling process in childhood or early adolescence. The metaphyses develop benign, bony outgrowths often capped by cartilage. A small number undergo neoplastic transformation.

**Tree numbers:** - C04.557.450.565.575.610.615.325 - C04.700.330 - C05.116.099.708.670.615.325 - C05.116.540.310.500 - C16.320.700.330

**Synonyms:** - Exostoses, Multiple, Type I - Exostosis, Familial - Exostosis, Hereditary Multiple - Exostosis, Multiple - Exostosis, Multiple Cartilaginous - Familial Exostoses - Hereditary Multiple Exostoses - Hereditary Multiple Exostosis - Multiple Cartilaginous Exostoses - Multiple Hereditary Exostoses - Multiple Osteochondromas - Multiple Osteochondromatosis - Osteochondromas, Multiple - Bessel-Hagen Disease - Chondrodysplasia, Hereditary Deforming - Diaphyseal Aclasis - Exostoses, Familial - Exostoses, Hereditary Multiple - Exostoses, Multiple Cartilaginous - Exostoses, Multiple