Mucopolysaccharidosis type I (MPS I, MIM #607014) is an autosomal recessive subtype of lysosomal storage disorders (LSD) caused by the build-up of glycosaminoglycans (GAGs) in the lysosomes, which occurs as a result of an absence or deficiency of α-L-iduronidase (IDUA) enzyme commission (EC) number 3.2. This evidence concerns the gene IDUA and lysosomal storage disease.