Objective: To analyze clinical and cytogenetic features of hematological disorders associated with 20q- and t (20;21) (q11;q11) abnormalities.
Methods: Following short-term culture of bone marrow cells, karyotypic analysis was carried out with R-banding. 20q- and t(20;21) (q11;q11) was detected by fluorescence in situ hybridization (FISH) using dual-color 20q11/12 probe, ST 20qter /ST 21qter probes, SE20(D20Z1)/SE 13/21 probes, and WC20/WC21 probes.
Results: Six (2.3%) of the 257 patients with 20q- detected by conventional karyotypic analysis were found to have t(20;21) (q11;q11) abnormality. Five cases had myelodysplastic syndrome, 1 had acute lymphoblastic leukemia. Above results were all confirmed by FISH.
Conclusion: i (20q-), t(20;21) (q11;q11) seems to be a rare but recurrent chromosomal abnormality which is specifically associated with myeloid disease, late occurrence and poor prognosis. The translocation between chromosome 20q11 and 21q11 may form a novel fusion gene which has an important role in the pathogenesis of the disease.