Hypophosphatasia: nonlethal disease despite skeletal presentation in utero (17 new cases and literature review).

Hypophosphatasia (HPP) is caused by deactivating mutation(s) within the gene that encodes the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP). Patients manifest rickets or osteomalacia and dental disease ranging from absence of skeletal mineralization in utero to only loss of adult dentition. Until recently, HPP skeletal disease in utero was thought to always predict a lethal outcome.