Pyrophosphate arthropathy in hypophosphatasia

The association of hypophosphatasia and pyrophosphate arthropathy in an adult patient has been described on 1 previous occasion. We report a further 2 patients with this disease combination. One patient suffers from the type of hypophosphatasia that presents in adult life, with fractures that are either spontaneous or the result of minimal trauma. The other patient suffered from the severe type of hypophosphatasia that presents in infancy but survived longer than is usual; the necropsy findings on this patient are reported.