Fanconi's anaemia. Simultaneous onset in 2 siblings and unusual cytological findings.

Fanconi's anaemia is reported in 2 siblings. The simultaneous onset of pancytopenia after possible exposure to common external agents suggest that both a frail genotype and environmental factors may be etiologically involved in the disorder. One of the children died after having developed a monoblastic leukaemia. This patient disclosed very striking cytological abnormalities, including a dyserythropoietic pattern and ropalocytosis. The physiopathology of the latter abnormality, which has hitherto not been noticed in Fanconi's anaemia, is uncertain.