Fanconi's anaemia developing erythroleukaemia.

A 15-year-old boy with Fanconi's anaemia (FA) for 10 years developed acute erythroleukaemia. During the leukaemic phase, granulopoietic stem cells (CFUc) were absent from his bone marrow and blood, but proliferation and differentiation of bone marrow cells could be seen in semipermeable diffusion chambers in vivo, and globin synthesis of erythroblasts had become imbalanced. Chromosomal lesions of peripheral blood lymphocytes differed in the leukaemic phase from those in the pancytopenic phase. These data indicate that erythro-, myelo-, thrombo-, and lymphocytic cell lines all were involved in both the leukaemic and the pancytopenic process. It is suggested that terminal myeloproliferative disease developed as part of the natural history of FA.