INCREASED CHROMOSOME FRAGILITY OF DONOR CELLS IN FANCONI'S ANEMIA AFTER BONE MARROW TRANSPLANTATION

Bone marrow transplantation appears to be an effective method of treatment of cases of Fanconi's anemia (FA) in the aplastic phase. A 20 year old Hispanic female with FA was successfully treated by bone marrow transplantation from her sister as donor. There was a polymorphism involving chromosome 20 between the donor and the recipient. Following the successful engraftment, karyotypes prepared from the blood of the recipient (presumably donor cells) had the karyotype of the donor. The chromosome breakage rate of the recipient before radiation and marrow transplant was 10.9 breaks per 100 mitotic cells using mitomycin C technique. The breakage rate of the donor before transplant was 2.0. Following the transplantation procedure, lymphocytes from the recipient (presumably donor cells) had a breakage rate of 9.8. These clinical and experimental findings suggest that a plasma or other marrow micro-environmental factor in FA may be responsible for the increased chromosomal fragility previously observed in this disease.