Hypophosphatasia: A case report

Hypophosphatasia (HPP) is a rare metabolic disorder caused by low tissue-nonspecific alkaline phosphatase (ALP) activity, presenting symptoms from bone demineralization to tooth loss. It affects multiple systems and is diagnosed based on clinical symptoms, radiological findings, and lab tests. This case report emphasizes considering HPP in patients with unexplained bone pain and low ALP levels, especially with underlying osteopenia or osteoporosis. It highlights the importance of genetic testing and counseling for early diagnosis and treatment, aiming to raise clinician awareness.

We present a case of a 65-year-old female patient who was referred to our endocrinology clinic for complaints of generalized bone pain and hypothyroidism. Initial evaluation revealed osteopenia, managed with calcium and vitamin D supplementation. Persistently low ALP levels and elevated vitamin B6 levels led to the diagnosis of HPP, confirmed by genetic testing identifying a pathogenic ALPL gene variant [c.119C>T (p.Ala40Val)]. Despite conservative treatment, her bone density declined, although remaining in the osteopenic range. The Fracture Risk Assessment score indicated a low risk of major osteoporotic and hip fractures, not warranting immediate treatment. Plans are underway to initiate enzyme replacement therapy with asfotase alfa.

Recognizing HPP is crucial, as early diagnosis and treatment can significantly improve patient outcomes and prevent complications.