Lysosomal IDUA enzyme activity, β-hexosaminidase enzyme activity, and GAG levels. (A) IDUA activity was measured in spleen, liver, heart, kidney, and lung of WT (n = 9), MPS I (n = 8), and MPS I nBMT-hi mice (n = 7) at 37 weeks of life. (B) The β-hexosaminidase activity was measured in the same organs of WT (n = 9), MPS I (n = 8), and MPS I nBMT-hi mice (n = 7) at 37 weeks of life. (C) At 37 weeks of age, the level of sulfated GAGs was determined, using the Blyscan assay in the indicated organs of WT (n = 9), MPS I (n = 8), and MPS I nBMT-hi (n = 7). (D) At 37 weeks of age, the levels of ΔDiHS-0S, ΔDiHS-NS, ΔDi-6S, and mono-sulfated Galβ1-4GlcNAc (6S) (mono-sulfated KS) were determined using liquid chromatography tandem mass spectrometry in the plasma of WT (n = 9), MPS I (n = 8), and MPS I nBMT-hi (n = 7). Median, mean, and minimum/maximum values are shown. Statistical comparison between groups was performed using Wilcoxon nonparametric unpaired test, 2 sides.