**5. Juvenile myelomonocytic leukemia (JMML)**

JMML is a rare myeloid disorder of childhood. Although the etiology of JMML is not known, children with neurofibromatosis type 1 (NF1) have high risk for developing JMML. Children diagnostic at 2 years old and up have a poorer prognosis. Thrombopenia and a high HbF level have also been associated with a poor prognosis. Currently, BMT appears to be the best therapy for JMML.
