A novel translocation t(3;22)(q21;q11) involving 3q21 in myelodysplastic syndrome-derived overt leukemia with thrombocytosis.

We report here a novel translocation t(3;22)(q21;q11) in myelodysplastic syndrome (MDS)-derived overt leukemia with thrombocytosis. A 44-year-old female was initially diagnosed as MDS with a low platelet count and normal karyotype. After 4 months, blood leukemic cells and platelets rapidly increased concomitantly and a diagnosis of acute myeloblastic leukemia (AML M1) was made. Chromosome analysis showed 46, XX, t(3;22)(q21;q11) in 14 of 20 metaphases. Fluorescence in situ hybridization analysis confirmed both the der(3)t(3;22) and the der(22)t(3;22). Our results suggest that unidentified gene(s) at 3q21 breakpoint may be implicated in the pathogenesis of abnormal thrombopoiesis as observed in the 3q21q26 syndrome.