Bone Marrow Transplantation Osteopetrosis occurs because there is a defect in cells called osteoclasts, which are necessary for the formation of bone marrow. In patients with osteopetrosis, osteoclasts don't work correctly and the cavity for bone marrow does not form. Few blood cells form because of the absence of bone marrow. Other blood-forming organs, particularly the spleen and liver, take over in blood production. As a result, these organs become greatly enlarged.
Bones look solid on X-ray, but are actually brittle.
Bone Marrow Transplantation allows the osteoclasts to be replaced with normal cells. This is the only approach that has resulted in a cure. Because of the high failure rate and side effects, this tends to be reserved for the most severe cases. Cord blood was used in lieu of bone marrow. The Red Cross said this was a very high participation.