Genomic instability in bone marrow failure syndromes.

Aneuploidy is frequently seen in leukemia and myelodysplasia (MDS) but was thought to be uncommon in aplastic anemia (AA). We examined marrow cells from 96 unselected patients with bone marrow failure syndromes to assess the frequency of undetected aneuploidy for chromosomes 7 and 8 by fluorescence in situ hybridization (FISH) as compared to routine cytogenetic analysis. Twenty-eight percent (27/96) of patients had an abnormal karyotype. FISH identified an additional 27 patients with undetected monosomy 7 or trisomy 8. Those patients with undetected monosomy 7 generally had a poor clinical outcome, suffering from lack of response to medical therapy or early death. In one AA/MDS patient with normal cytogenetics, FISH identified a large population of monosomy 7 cells, which clearly heralded a clinical relapse. In another patient, FISH studies were used to delineate instability of chromosome 8, with apparent disease progression from AA to MDS. We conclude that undetected aneuploidy exists in marrow cells of a significant percentage of patients with bone marrow failure syndromes.