Mucopolysaccharidosis type I (MPS I) is a rare autosomal recessive disorder caused by deficiency of lysosomal hydrolase alpha-L-iduronidase (IDUA, EC 3.2.1.76), involved in the degradation of glycosaminoglycans (GAG) heparan sulphate (HS) and dermatan sulphate (DS). This evidence concerns the gene IDUA and Scheie syndrome.