set eyes Diamond-shaped eyebrows Ears that are low-set, backward-rotated, thick outer rim Deeply grooved philtrum (upper lip line) Learning delays Genetics About 90% of JMML patients have some sort of genetic abnormality in their leukemia cells that can be identified with laboratory testing. This includes: 15-20% of patients with neurofibromatosis 1 (NF1) 25% of patients with mutations in one of the RAS family of oncogenes (only in their leukemia cells) Another 35% of patients with a mutation in a gene called PTPN11 (again, only in their leukemia cells). Diagnosis The following criteria are required in order to diagnose JMML: All 4 of the following: No Philadelphia chromosome or BCR/ABL fusion gene. Peripheral blood monocytosis >1 x 109/L. Less than 20% blasts (including promonocytes) in the blood and bone marrow (blast count is less than 2% on average) Splenomegaly At least one of: Mutation in RAS or PTPN11 Diagnosis of neurofibromatosis 1 Chromosome 7 monosomy Or two or more of the following criteria: Hemoglobin F increased for age. Immature granulocytes and nucleated red cells in the peripheral blood. White blood cell count >10 x 109/L. Clonal chromosomal abnormality (e.g., monosomy 7). Granulocyte-macrophage colony-stimulating factor (GM-CSF) hypersensitivity of myeloid progenitors in vitro. These criteria are identified through blood tests and bone marrow tests. The differential diagnosis list includes infectious diseases like Epstein–Barr virus, cytomegalovirus, human herpesvirus 6, histoplasma, mycobacteria, and toxoplasma, which can produce similar symptoms. Treatment There are two internationally accepted treatment protocols, which are geographically based: North America: the Children's Oncology Group (COG) JMML study Europe: the European Working Group for Myelodysplastic Syndromes (EWOG-MDS) JMML study The following procedures are used in one or both of the current clinical approaches listed above: Splenectomy The theory behind splenectomy in JMML is that the spleen may trap leukemic cells, leading to the spleen's enlargement, by harboring dormant JMML cells that are not eradicated by radiation therapy or chemotherapy for the active leukemia cells, thus leading to later relapse if the spleen is not removed. However, the impact of splenectomy on post-transplant relapse, though, is unknown. The COG JMML study includes splenectomy as a standard component of treatment for all clinically stable patients. The EWOG-MDS JMML study allows each child's physician to determine whether or not a splenectomy should be done, and large spleens are commonly removed prior to bone marrow transplant. When a splenectomy is scheduled, JMML patients are advised to receive