Hypophosphatasia: A missed diagnosis

Hypophosphatasia is a disorder of bone metabolism due to defective tissue nonspecific alkaline phosphatase (ALP). It is most severe in early life but can present at any age, leading to a likely underdiagnosis of its adult, and commonly less severe, forms. This is the case of a 42-year-old female who presented to endocrinology asking about her low ALP levels in the setting of prior bilateral metatarsal fractures and was diagnosed with hypophosphatasia. This case report aims to highlight the importance of making this diagnosis in order to avoid commonly prescribed therapies that can be harmful. Antiresorptive therapies as well as supplementation with calcium or Vitamin D can potentially worsen the disease. There are no Food and Drug Administration-approved treatments for adult hypophosphatasia, but asfotase alfa and teriparatide are two promising therapies currently being studied. The following core competencies are addressed in this article: Practice-based learning and improvement, Medical knowledge.