Osteopetrosis is an inherited disorder characterized by the inability to reabsorb and remodel bone due to osteoclast dysfunction. The encroachment by bone and mineralized cartilage of the medullary cavities leads to extramedullary hematopoiesis (hepatosplenomegaly) and cranial-nerve foramina leads to blindness, auditory nerve damage, and occulomotor and facial nerve palsies. Defective bone re-absorption also leads to macrocephaly, frontal bossing, hypertelorism, exophthalmos, increased intracranial pressure, retarded tooth eruption, retarded linear growth and psychomotor delay. Death occurs within the first years of life. The only curative therapy is allogeneic bone marrow transplantation with a HLA-identical donor, which restores hematopoiesis, monocyte-macrophage function and bone recovery, but there is no sensorial deficit restoration once present. The authors report two cases of allogeneic bone marrow transplant for infantile malignant osteopetrosis. The first child, on day 1260 after bone marrow transplantation (BMT), showed radiologic bone recovery and no progression of neurological deficits with a bone biopsy showing no signs of osteopetrosis. The second child showed signs of bone re-absorption and no progression of neurological deficits on day 700. The authors emphasize the importance of early diagnosis of osteopetrosis and the necessity of bone marrow transplantation before neurological deficits have begun.
Osteopetrosis; bone marrow transplantation
