UDP-glucuronic acid decarboxylase 1 is an enzyme that in humans is encoded by the UXS1 gene. UDP-glucuronate decarboxylase (UGD; EC 4.1.1.35) catalyzes the formation of UDP-xylose from UDP-glucuronate. UDP-xylose is then used to initiate glycosaminoglycan biosynthesis on the core protein of proteoglycans.[supplied by OMIM]