The Journal of Bone and Joint Surgery, Vol 62, Issue 3 384-399, Copyright © 1980 by Journal of Bone and Joint Surgery, Inc
Human osteopetrosis: a histological, ultrastructural, and biochemical study
F Shapiro, MJ Glimcher, ME Holtrop, AH Tashjian, D Brickley-Parsons and JE Kenzora
Histological ultrastructural, and biochemical studies of the tissues of a
patient with osteopetrosis were done. The bone contained an increased
number of osteoclasts which were characterized ultrastructurally by the
absence of ruffled borders and clear zones, hallmarks of actively resorbing
osteoclasts. In contrast with normal human bone, tissue collagenase was not
detected in osteopetrotic bone cultured in vitro, nor was tissue
collagenase activity released when the osteopetrotic bone was incubated
with parathyroid hormone. No striking abnormalities of parathyroid hormone
or calcitonin were found in the blood or parathyroid and thyroid glands.
Except for a slight increase in the extent of lysine hydroxylation of bone
collagen, no significant biochemical abnormality of collagen was found. The
histological, ultrastructural, and biochemical data support the hypothesis
that the basic defect in osteopetrosis is cellular and the osteoclasts, in
particular, are abnormal. They appear to be unable to resorb bone and
cartilage, and they do not appear to respond to parathyroid hormone in a
completely normal way. Clinical Relevance: Bone marrow transplantation has
produced improvement in both experimental animals and humans and should be
actively considered in a child with osteopetrosis who is not thriving.