Exostosin 1

**Definition:** A bifunctional glycosyltransferase involved in transferring GLUCURONIC ACID and N-ACETYLGLUCOSAMINE in the elongation of HEPARAN SULFATE chains. Mutations in the gene EXT1, coding for this protein (as well as mutations in other genes), are responsible for defects in heparan sulfate synthesis resulting in HEREDITARY MULTIPLE EXOSTOSES. Exostosin-1, along with EXOSTOSIN-2, is a component of heparan sulfate polymerase.

**Tree numbers:** - D08.811.913.400.001.250 - D08.811.913.400.100.250.250

**Synonyms:** - Exostosin-1 - EXT1 Heparan Sulfate Copolymerase - Heparan Sulfate Copolymerase EXT1 - Multiple Exostoses Protein 1