Current guidelines recommend the initiation of long-term elosulfase alfa (Vimizim®, BioMarin Pharmaceutical Inc., Novato, CA), a recombinant human GALNS enzyme replacement therapy (ERT) approved for the treatment of MPS IVA [7, 8], in all patients as soon as possible after a confirmed diagnosis [9]. Here, GALNS is linked to mucopolysaccharidosis type 4A.