Cytoxan, Fludara, and Antithymocyte Globulin Conditioning Followed By Stem Cell Transplant in Treating Fanconi Anemia

OBJECTIVES: Primary * To determine the probability of engraftment in patients with Fanconi anemia treated with cyclophosphamide, fludarabine phosphate, and antithymocyte globulin followed by HLA-genotypically identical sibling donor hematopoietic stem cell transplantation that is T-cell depleted. Secondary * To evaluate the incidence of acute graft-versus-host disease (GVHD) and chronic GVHD in patients treated with this regimen. * To evaluate the incidence of regimen-related toxicity in these patients. * To evaluate the 1-year survival of patients treated with this regimen. * To evaluate the incidence of late secondary malignancies (e.g., squamous cell carcinoma of the head and neck or cervix) in patients treated with this regimen. OUTLINE: * Preparative cytoreductive therapy: Patients receive cyclophosphamide IV over 2 hours on days -6 to -3 and fludarabine phosphate IV over 30 minutes and anti-thymocyte globulin IV over 4-6 hours on days -6 to -2. * T-cell depleted donor hematopoietic stem cell transplantation: Patients undergo T-cell depleted donor bone marrow or umbilical cord blood stem cell transplantation on day 0. Patients also receive filgrastim (G-CSF) IV beginning on day 1 and continuing until blood counts recover. * Graft-versus-host disease prophylaxis: Patients receive cyclosporine IV over 2 hours or orally every 8-12 hours beginning on day -3 and continuing until day 100, followed by a taper. Patients will receive Mycophenolate Mofetil (MMF) therapy beginning on day -3 through day +30 or for 7 days after engraftment, whichever day is later, if no acute GVHD. Engraftment is defined as 1st day of 3 consecutive days of absolute neutrophil count \[ANC\] \> 0.5 x 10\^9/L. After completion of study therapy, patients are followed periodically.