Multiple Hereditary Exostosis, EXT Genes, and Skeletal Development

ultiple hereditary exostosis is an autosomal domi-nant inherited disease in which osteochondral growths occur on the periphery of bones. These growths are comprised of bone surrounded by a cap of cartilage. A small number of these exostoses proceed to a low-grade chondrosar-coma1,2. Although the disease can occur spontaneously, it has been estimated that 80 % of affected individuals have a positive family history2. Research on the genetics of multiple hereditary exostosis over the past thirty years has been productive. Advances in the understanding of the disease have paralleled the methodologi-cal advances that have occurred in the field of molecular ge-netics. Initially, it was recognized that multiple hereditary exostosis is often inherited and that large families were available for genetic mapping. As techniques for gene mapping im