Bone marrow failure syndrome unresponsive to therapy, including but not limited to the following: Congenital pure red cell aplasia (Diamond Blackfan anemia) Confirmed by bone marrow aspirate More than 6 transfusions per year despite steroid therapy Kostmann's neutropenia Confirmed by bone marrow aspirate Unable to maintain absolute neutrophil count greater than 750/mm3 or recurrent life threatening infections or more than 4 hospitalizations per year despite therapy with filgrastim (G-CSF) No myelodysplasia or aplastic anemia