Hematopoietic Stem Cell Transplantation in High Risk Patients With Fanconi Anemia

OBJECTIVES: Primary * Determine whether the incidence of neutrophil engraftment is acceptable in high-risk patients with Fanconi's anemia treated with busulfan, cyclophosphamide, fludarabine, and antithymocyte globulin followed by allogeneic hematopoietic stem cell transplantation. Secondary * Determine the tolerability of mycophenolate mofetil in these patients. * Determine the incidence of acute and chronic graft-vs-host disease in patients treated with this regimen. * Determine the incidence of major infections in patients with a history of major infections treated with this regimen. * Determine the incidence of relapse in patients with refractory anemia with excess blasts, refractory anemia with excess blasts in transformation, or acute myeloid leukemia treated with this regimen * Determine the probability of 1-year survival of patients treated with this regimen. OUTLINE: Patients are stratified according to donor/recipient HLA type (identical vs other). * Cytoreductive combination chemotherapy: Patients receive busulfan intravenously (IV) over 2 hours twice daily on days -7 and -6 and cyclophosphamide IV over 2 hours and fludarabine IV over 30 minutes once daily on days -5 to -2. * Graft failure prophylaxis: Patients receive methylprednisolone IV twice daily on days -5 to 30 and anti-thymocyte globulin IV over 4-6 hours twice daily on days -5 to -1. * Graft-vs-host disease prophylaxis: Patients receive cyclosporine IV over 2 hours twice daily on days -3 to 100 (if patient has a matched sibling donor) or days -3 to 180 (if patient has another donor type). Patients also receive mycophenolate mofetil orally or IV twice daily on days -3 to 45. * Allogeneic hematopoietic stem cell transplantation (HSCT): Patients undergo allogeneic HSCT (using bone marrow or umbilical cord blood) on day 0. Patients receive filgrastim (G-CSF) subcutaneously beginning on day 1 and continuing until blood counts recover. After completion of study treatment, patients are followed periodically for 3 years.