At the same time the patient demonstrated the currently used diagnostic criteria for JMML as well (see Section 1), that is, hepatosplenomegaly, persistent peripheral blood monocyte count > 1 × 109/L, no Philadelphia chromosome or BCR-ABL fusion gene, bone marrow blasts 4%, myeloid blasts in the peripheral blood 1-2%, and peripheral blood white blood cell count 85.4 × 109/L. The gene discussed is ABL1; the disease is juvenile myelomonocytic leukemia.