Abstract: Objective To investigate clinical characteristics of GATA 1 -positive non-Down syndrome (DS) acute megakaryoblastic leukemia (AMKL). Methods Clinical data of two children with AMKL were retrospectively analyzed, and related literatures were reviewed. Results Case one was a 2 -year-old girl diagnosed as AMKL by bone marrow morphology, immunotyping, molecular and genetic analysis, with no special facial features or developmental delay. Bone marrow chromosome karyotype at the beginning showed 50, XX, +8, +10, +21, +21[7]/46, XX[13]. Gene test identified a mutation of c.52dupT in GATA1 gene. After induction chemotherapy, peripheral blood chromosome showed 46 , XX. Now she has a disease-free survival. Case two was a 1 -year-old boy diagnosed as acute AMKL without Down's special features. The karyotype of bone marrow at the beginning was 47 , XY, + 21 [ 10 ]/ 46 , XY[10 ]. Gene test identified a mutation in GATA1 , and chromosome reexamination after bone marrow remission chemotherapy showed 46 , XY. Continuous bone marrow remission was observed at a 30 -month follow-up. Conclusion These cases emphasize that the importance of GATA1 testing for the non-DS AMKL.

Key words: AMKL; non-Down Syndrome; GATA1 -positive