Mucopolysaccharidosis type 1 (MPS I) is an autosomal recessive lysosomal disorder caused by deficiency of the enzyme α-L-iduronidase (IDUA) resulting in an accumulation of the glycosaminoglycans (GAG) heparan sulfate and dermatan sulfate.1 This evidence concerns the gene IDUA and mucopolysaccharidosis type 1.