Hypophosphatasia.

Hypophosphatasia is a rare inherited metabolic disease characterised by reduced plasma and tissue alkaline phosphatase activity, and may present in infancy, childhood or adulthood. The differing modes of inheritance, presentation and natural history are likely to reflect variable expression of the alkaline phosphatase gene defect. A case of infantile hypophophatasia presenting with hypercalcaemia is described and the histological and radiological resolution of the mineralisation defect present initially are reported.