PROTOCOL OUTLINE: Patients receive filgrastim (G-CSF) subcutaneously daily on days 0-6 followed by apheresis to collect peripheral blood stem cells (PBSC) on days 5-7. PBSCs are processed in vitro for enrichment of CD34 cells and transduced with a Fanconi's anemia complementation C (FACC) retroviral vector on days 5-10. Patients receive transduced PBSCs IV over no more than 2 hours on days 8-10. PBSC infusions may be repeated no more than every 2 months for up to 4 courses total.