Acute megakaryoblastic leukemia with a four-way variant translocation originating the RBM15-MKL1 fusion gene.

Acute megakaryoblastic leukemia (AMKL) with t(1;22)(p13;q13) is a subset of acute myeloid leukemia (AML) representing <1% of all cases and about 70% of pediatric AMKL in the first year of life. We present a case of a 7-month-old female in whom the bone marrow karyotype showed the derivative chromosome der(22)t(1;22)(p13;q13). The RBM15-MKL1 fusion transcript was detected by RT-PCR and confirmed by sequencing analyses. FISH analyses revealed the presence of the four-way translocation t(1;22;17;18)(p13;q13;q22;q12).