The overall scores calculated for NP1, Ch3L1, CD14, and IGFBP2 almost reached control values in early-treated MPS I dogs, while the corresponding values for late-treated MPS I dogs were similar to those for untreated MPS I dogs—suggesting that the overall score can predict the efficacy of gene therapy in the canine model of Hurler syndrome. The gene discussed is NPTX1; the disease is Scheie syndrome.