The main cause of mucopolysaccharidosis type I (Hurler syndrome OMIM #607014, Scheie syndrome OMIM #607016, Hurler-Scheie syndrome OMIM #607015) is a mutation in the α-L-iduronidase (IDUA) gene, which results in a deficiency or relative deficiency of the α-L-iduronidase enzyme. The gene discussed is IDUA; the disease is Scheie syndrome.