Chronic familial hyperphosphatasemia.

Two siblings displaying macrocrania and multiple skeletal deformities, as well as cardiomegaly, had high levels of serum alkaline phosphatase and markedly increased urinary hydroxyproline excretion. The radiological findings of chronic familial hyperphosphatasemia, which are typical of a rare bone-remodeling disease, are presented. Scintigraphy disclosed intense uptake of the radionuclide by the skeletons of both patients. This finding, considered to be related to abnormal collagen metabolism, can be used in the diagnosis and assessment of skeletal involvement in such patients.