Idursulfase (ELAPRASE®, Takeda, Lexington, MA), a purified recombinant form of IDS produced in human cell lines, administered intravenously at a weekly dosage of 0.5 mg/kg in patients with MPS II demonstrated significant improvements in multiple markers of cardiorespiratory health compared to the placebo group, including 6-minute-walk distance, predicted forced vital capacity, and absolute forced vital capacity [9] resulting in enzyme replacement therapy becoming an FDA-approved treatment for MPS II [10]. Here, IDS is linked to mucopolysaccharidosis type 2.