Faconi anemia and bone marrow clonal chromosome abnormalities.

Clonal chromosome abnormalities were detected in bone marrow cells of 20 patients with Fanconi anemia investigated at various stages of the disease. Two presented with acute leukemia, six with myelodysplastic syndrome, and 12 had minor or no morphological abnormalities of hematopoietic cells. Abnormalities of chromosome 7 were detected in nine patients (monosomy, isochromosome, or other structural rearrangement), and chromosome 1 was rearranged in four. The types and the significance of clonal chromosome abnormalities which may be present without apparent evolution toward acute leukemia or myelodysplastic syndrome in Fanconi anemia patients are discussed.