The IDUA mutations, p.Trp402ter (rs121965019) and p.Pro533Arg (rs121965021), have been already reported to account for more than 50% of MPSI alleles in most populations.7 The influence of mutations on IDUA enzyme activity has broad variability, and thus, IDUA is provided in different forms; however, there is not a significant relationship between the IDUA genotypes and various phenotypes that are observed in MPSI. This evidence concerns the gene IDUA and mucopolysaccharidosis type 1.