ALPL and osteoporosis: To date, the only treatment approved for patients with HPP is bone‐targeted enzyme‐replacement therapy with asfotase alfa.9 Bisphosphonates are generally considered to be contraindicated in HPP because they can inhibit mineralization and because bisphosphonate treatment of adult patients with mild HPP has been associated with atypical femoral fractures.6, 9, 26, 27 In this study, 10 patients with potentially damaging ALPL variants and osteoporosis had been treated with bisphosphonates and were followed up for an average of just over 6 years.