Clinically, the child presented with fever, diarrhea, normal white blood cell count (5.9 × 109/L) without circulating abnormal cells, anemia, thrombocytopenia, and hepatomegaly; bone marrow examination showed hypercellularity with agranular lymphoid blast cells expressing pre-B immunophenotype (cyCD79α+CD19+sCD22+CD10+CD34+sIgM−) and dim myeloid-associated markers (CD13+CD33+). This evidence concerns the gene CD33 and Thrombocytopenia.