[Clonal chromosomal aberrations in patients with aplastic anemia at the disease onset and transformation]

To estimate detectability and characteristic features of chromosomal aberrations in bone marrow cells of patients with aplastic anemia (AA).

The trial covered 155 AA patients admitted to the Hematological Research Center in 1987-2002. Cytogenetic study by G-differential staining was performed in 58 patients with AA and 5 patients with AA transforming into myelodysplastic syndrome (MDS) or acute leukemia (AL). Cytogenetic and morphological specimens of the latter's bone marrow were studied retrospectively using fluorescent in situ hybridization (FISH) with DNA probes for detection of monosomia 7 and deletion 7q.

Clonal chromosomal aberrations were detected in 4 out of 28 patients. Further examinations revealed no aberrations. Clonal diseases developed in 7 (4.5%) of 155 patients. In 2 patients the disease transformed into paroxysmal nocturnal hemoglobinuria, 5 (3.2%) patients developed variants of MDS and AL. Monosomia 7 or deletion 7q were diagnosed in 3 cases of MDS/AL. In retrospective study of bone marrow specimens of patients with transformation in MDS/AL with monosomia 7, FISH recognized a small elevation over control values in 2 cases.

Stable clonal chromosomal aberrations are not characteristic of AA. Some AA patients with subsequent MDS/AL may have minor neoplastic clone in the disease onset.