This study is designed to determine whether hematopoietic progenitors transduced with the normal FACC gene can be re-infused safely into FA(C) patients. CD34+ cells obtained from G-CSF mobilized peripheral blood will be transduced ex vivo over a 72 hour period in the presence of IL-3, IL-6, and stem cell factor with the FACC retroviral vector. These transduced cells will be re-infused into FA(C) patients. Patients will be monitored for toxicities as well as evidence of successful gene transfer and expression. The procedure will be repeated up to a total of 4 times with each treatment 2-4 months apart. Theoretically, these rescued stem cells should have a selective growth advantage within the hypoplastic FA marrow environment in vivo.