Hypophosphatasia

Hypophosphatasia is characterised by low serum alkaline phosphatase levels and defective bone and tooth mineralisation. It presents with a broad spectrum of severity, ranging from perinatal lethal forms to mild adult-onset or odontohypophosphatasia. Clinical features may include skeletal deformities, fractures, premature tooth loss, and muscle weakness. Radiographically, it can mimic rickets or osteomalacia. Diagnosis is confirmed with low ALP levels, elevated substrates (like pyridoxal 5’-phosphate), and genetic testing. Enzyme replacement therapy (asfotase alfa) is approved for severe cases and has significantly improved outcomes. Orthopaedic care focuses on fracture management and skeletal support.