Juvenile CML is characterized by all EXCEPT:

-JMML is a childhood mixed MDS/MPD that includes childhood leukemias previously classified as CMML, juvenile CML, and infantile monosomy 7 syndrome. - Remember: presence of bcr/abl fusion (Philadelphia chromosome) is not compatible with a diagnosis of juvenile myelomonocytic leukemia (JMML). Diagnostic criteria of JMML: Category -1 - Age < 13yrs - Splenomegaly - Absolute monocyte count >1000/cu mm - Blasts in peripheral blood/marrow < 20% - Absent philadelphia chromosome & BCR/ ABL fusion gene Category -2 - Somatic mutation in RAS/ PTPN11 - Clinical diagnosis of NF-1/ Monosomy-7 Categoty - 3 - Circulating myeloid precursors - Leukocytes > 10,000/cu mm - Elevated fetal Hb, HbF - clonal cytogenetic abnormalities