Transplantation of cord blood progenitor cells can promote bone resorption in autosomal recessive osteopetrosis

Allogeneic BMT has been reported to be the only curative therapy for children with juvenile autosomal recessive osteopetrosis. We report the case of a 14-month-old child in whom bone resorption was observed after cord blood transplantation (CBT). The patient was given CBT from an unrelated newborn matched for five of six HLA antigens. At the time of transplantation, the child presented with neurological symptoms, with feeding problems and visual impairment. A successful engraftment of donor hematopoiesis was demonstrated and the child experienced grade I acute GVHD. Progressive bone clearing was achieved and a bone marrow trephine demonstrated signs of osteoclast function. Despite full engraftment and bone resorption, neurologic deterioration did not improve. This experience documents that CBT can promote the correction of juvenile osteopetrosis. The shorter time needed both to identify an unrelated donor and to perform the transplant, as well as the lower incidence of GVHD make this procedure more appealing than BMT in children lacking an HLA-compatible relative.