Indeed, the clinical success of several ERT regimens for many diseases including MPS I (laronidase), MPS II (idursulfase), MPS VI (galsulfase), Pompe disease (alglucosidase alfa), Gaucher disease (imiglucerase), Fabry disease (agalsidase β), and Batten disease (cerliponase alfa) indicate that rhGNS will likely have a significant clinical role even if further research into gene therapy is pursued [42,43,60,61]. Here, IDS is linked to juvenile neuronal ceroid lipofuscinosis.