Three adult cases resembling hereditary bone dysplasia.

Hereditary bone dysplasia with hyperphosphatasemia is a generalized disorder of bone formation which begins in infancy, uniformly involves the skull and long bones and results in progressive deformities and short stature. This entity has been described 27 times under various names, including juvenile Paget's disease, but only two case reports have described the condition in adults. In the present report two siblings and an unrelated individual are described with features resembling hereditary bone dysplasia. In all three the condition developed in infancy but was first recognized in middle age. Clinical and radiographic features of short stature, extensive thickening of the calvarium with areas of "cotton wool sclerosis", and bowed deformities of the long bones were present. The serum alkaline phosphatase was elevated in one case and normal in two. One patient demonstrated a marked clinical and biochemical response to a six month course of disodium etidronate after failing to respond to a trial of salmon calcitonin. There were significant differences between these three cases and classic hereditary bone dysplasia as described in infants and children. The patients themselves also had variable features. These observations suggest that either hereditary bone dysplasia is indeed variable, especially as afflicted children pass into adulthood, or different skeletal diseases are presently being included under the general term hereditary bone dysplasia with hyperphosphatasemia.