Atypical chronic myelogenous leukemia (aCML), BCR/ABL1 negative is a rare disorder classified into the category of myelodysplastic/myeloproliferative neoplasms (MDS/MPN), according to the 2016 revision of the World Health organization (WHO) classification of myeloid neoplasms and acute leukemia (1). The gene discussed is ABL1; the disease is myeloproliferative disorder.