Meta-Biol

• Pathways

Exostosin 1 and 2 (EXT1 and 2) are dual-specific glycosyltransferases required to form heparan sulfate (HS) which is involved in regulating various body functions during development, homeostasis and pathology including blood clotting, angiogenesis and metastasis of cancer cells. They are able to transfer N-acetylglucosamine (GlcNAc) and glucuronate (GlcA) to HS during its synthesis. Defects in EXT2 cause exostoses 2 (MIM:133701), an autosomal dominant disorder characterised by multiple projections of bone capped by cartilage resulting in deformed legs, forearms and hands. Mutations causing exostoses 2 are V187Pfs*115, A361Pfs*44, D227N, G172*, Q258* and Y222* (Stickens et al. 1996, Wyuts et al. 1996, Philippe et al. 1997, Heinritz et al. 2009).