Transient expression of trisomy 21 and monosomy 7 following cyclosporin A in a patient with aplastic anemia.

We present a patient with severe idiopathic aplastic anemia with no previous chromosomal abnormalities who developed trisomy 21 and monosomy 7 during treatment with intravenous (i.v.) cyclosporine. The abnormal karyotype disappeared when the drug was changed to the oral form. This cytogenetic aberration, previously unreported in association with cyclosporine, may reflect either a direct drug effect or the emergence of a hidden myelodysplastic cell clone subject to preferential survival during immunosuppression.