A case of atypical femoral fracture under antiresorptive therapy in an HPP patient has been published; it shows the importance of avoiding antiresorptive therapy in all carriers of an ALPL mutation or overt HPP patients.25 In this study, 2 patients (case 1 and case 3) had been treated with antiresorptives. The gene discussed is ALPL; the disease is hypophosphatasia.