EXT1

EXT1 is a gene that provides instructions for making an enzyme called exostosin-1. This enzyme is part of a complex that produces heparan sulfate, a long chain of sugar molecules that attach to proteins and form proteoglycans. Proteoglycans are found on the surface of cells and in the extracellular matrix, the lattice of proteins and other molecules outside the cell. Heparan sulfate proteoglycans have many functions, including regulating the growth and division (proliferation) of cells and the process by which cells mature to carry out specific functions (differentiation).

Function

The EXT1 gene is located on the short (p) arm of chromosome 8 at position 24.1. This gene is active (expressed) in many tissues, but it is not well understood why mutations that eliminate the function of one copy of the EXT1 gene lead specifically to the formation of osteochondromas.

Clinical significance

Mutations in the EXT1 gene are responsible for multiple osteochondromas, a condition characterized by the development of multiple benign (noncancerous) bone tumors called osteochondromas. The number of osteochondromas and the bones they affect vary greatly among affected individuals. Osteochondromas can cause skeletal abnormalities including deformities and short stature. In some cases, these growths can cause pain and nerve damage.

See also

• EXT2
• Multiple osteochondromas

External links

• EXT1 at Genetics Home Reference
• EXT1 at National Center for Biotechnology Information

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