ALPL and Onset: In October 2015, the FDA approved asfotase alfa, a bone‐targeted human recombinant TNSALP replacement therapy for patients with perinatal‐, infantile‐ and juvenile‐onset HPP.3 This recombinant glycoprotein contains the catalytic domain of TNSALP, human immunoglobulin G1 Fc domain, and a deca‐aspartate peptide, which attaches to bone.