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Juvenile myelomonocytic leukemia

Disease definition

A rare myelodysplastic/myeloproliferative neoplasm characterized by a proliferation primarily of granulocytic and monocytic lineages with infiltration of the liver and spleen, among other organs. Blasts and promonocytes account for less than 20% of white blood cells in peripheral blood and bone marrow. Erythroid and megakaryocytic abnormalities are often present. BCR-ABL1 fusion is absent, while somatic mutations in genes of the RAS pathway or monosomy 7 may be found. The condition may also occur in the context of neurofibromatosis type 1 or Noonan syndrome-like disorder. Children of less than three years are predominantly affected, with a clear male preponderance. Most patients present with constitutional symptoms, signs of infection, and hepatosplenomegaly.


Classification level: Disorder
  • Synonym(s):
    • JMML
    • Juvenile chronic myelomonocytic leukemia
  • Prevalence: 1-9 / 1 000 000
  • Inheritance: Not applicable 
  • Age of onset: Childhood, Infancy
  • ICD-10: C93.3
  • ICD-11: 2A42
  • OMIM: 607785
  • UMLS: C0349639
  • MeSH: D054429
  • GARD: 9884
  • MedDRA: 10023249
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