Stem Cell Transplant (SCT) for Dyskeratosis Congenita or SAA

Transplantation with stem cells is a standard therapy in many centers around the world. Previous experience with stem cell transplantation therapy for leukemias, lymphomas, other cancers, aplastic anemia and other non-malignant diseases, has led to prolonged disease-free survival or cure for some patients. However, the high doses of pre-transplant radiation and chemotherapy drugs used, and the type of drugs used, often cause many side effects that are intolerable for some patients. Slow recovery of blood counts is a frequent complication of high dose pre-transplant regimens, resulting in a longer period of risk for bleeding and infection plus a longer time in the hospital. Recent studies have shown that using lower doses of radiation and chemotherapy (ones that do not completely kill all of the patient's bone marrow cells) before blood or bone marrow transplant, may be a better treatment for high risk patients, such as those with Dyskeratosis Congenita (DC) or Severe Aplastic Anemia(SAA). These low dose transplants may result in shorter periods of low blood counts, and blood counts that do not go as low as with traditional pre-transplant radiation and chemotherapy. Furthermore, in patients with Dyskeratosis Congenita or SAA, the stem cell transplant will replace the blood forming cells with healthy cells. It has recently been shown that healthy marrow can take and grow after transplantation which uses doses of chemotherapy and radiation that are much lower than that given to patients with leukemia. While high doses of chemotherapy and radiation may be necessary to get rid of leukemia, this may not be important to patients with Dyskeratosis Congenita or SAA. The purpose of this research is to see if this lower dose chemotherapy and radiation regimen followed by transplant is a safe and effective treatment for patients with Dyskeratosis Congenita or SAA.