IDUA and lysosomal storage disease: Mucopolysaccharidosis type I (MPS I) is a rare lysosomal storage disorder caused by deficiency of the enzyme alpha-L-iduronidase (IDUA) which is involved in the degradation of the glycosaminoglycans (GAGs) dermatan sulphate and heparan sulphate and has an estimated birth incidence of 1 in every 100.000 live births [1, 2].