IDUA and Scheie syndrome: Mucopolysaccharidosis type I (MPS I), often referred to by the eponyms Hurler, Hurler-Scheie, and Scheie syndromes depending upon degree of central nervous system (CNS) involvement and velocity of disease progression, results from a deficiency of the activity of α-l-iduronidase (IDUA) and results in tissue storage of the GAG species heparan sulfate (HS) and dermatan sulfate (DS).