Assessment of Vitamin D Status and Calcium–Phosphate Metabolism in Patients with Hypophosphatasia—A Single-Center Cohort Study

Background

Hypophosphatasia (HPP) is a rare genetic disorder caused by a loss-of-function mutation in the ALPL gene, which encodes tissue-nonspecific alkaline phosphatase (TNSALP). Reduced TNSALP activity in HPP primarily leads to bone mineralization disorders. Given the complex and challenging nature of issues related to vitamin D and HPP, it is essential to evaluate each patient individually and adjust the appropriate dose of vitamin D according to their specific needs in order to maintain calcium phosphate homeostasis and normal vitamin D levels. Maintaining proper vitamin D homeostasis in patients with hypophosphatasia is one of the greatest challenges.