[Fanconi's anemia: chromosome anormalies].

Two types of chromosome abnormalitie are observed in the bone marrow and the blood of a patient with Fanconi's anemia. There abnormalities involved in two stages: firstly the presence of a clone with 47 chromosomes + 21, which was not found during later examinations. One and a half years later, following a decline in the hematological condition, there appeared duplication of certain chromosome segments of the long arm of the 3 chromosome and of the intermediate segment of the long arm of the 12 chromosome. This latter type of abnormality affected differently the bone marrow and the blood in the bone marrow, we found 2 clones, one bore 2 markers obtained from 3 and 12, the other and marker obtained from the 12 chromosome. In the blood, there was simply a minority clone with only the marker originating in the 3 chromosome. This observation should be compared with the descriptions made by other authors. In all cases abnormal clones present an apparently unbalanced karyotype, characterised by excess material.