ALPL and hypophosphatasia: Hypophosphatasia (HPP, OMIM: 146300, 241500, 241510) is a rare inherited mineral metabolism disorder caused by low enzymatic activity in the tissue nonspecific alkaline phosphatase (TNSALP) as a result of mutations (pathogenic variants) in the ALPL gene that is localized on chromosome 1p36.12 [1].