Acute megakaryoblastic leukemia (AMKL) is life-threatening leukemia in which malignant megakaryoblasts proliferate abnormally and injure various tissues. Megakaryoblasts are the most immature precursor cells in a platelet-forming lineage; they mature to promegakaryocytes and, ultimately, megakaryocytes which cells shed membrane-enclosed particles, i.e. platelets, into the circulation. Platelets are critical for the normal clotting of blood. While malignant megakaryoblasts usually are the predominant proliferating and tissue-damaging cells, their similarly malignant descendants, promegakaryocytes and megakaryocytes, are variable contributors to the malignancy.AMKL is commonly regarded as a subtype of acute myeloid leukemia (AML). More formally, it is classified under the AML-M7 category of the French-American-British classification and by the World Health Organization of 2016 in the AML-Not Otherwise Specified subcategory.Acute megakaryoblastic leukemia falls into three distinct groups which differ in underlying causes, ages of presentation, responses to therapy, and prognoses. These groups are: AMKL occurring in young children with Down syndrome, i.e. DS-AMKL; AMKL occurring in children who do not have Down syndrome, i.e. non-DS-AMKL (also termed pediatric acute megakaryoblastic leukemia or pediatric AMKL); and AMKL occurring in non-DS adults, i.e. adult-AMKL. AMKL, while rare, is the most common form of AML in DS-AMKL, occurring ~500-fold more commonly in Down syndrome children than in children without Down syndrome; non-DS-AMKL and adult-AMLK are rare, accounting for <1% of all individuals diagnosed as in the AML-M7 category of leukemia. DS-AMKL
Pathophysiology
Individuals with Down syndrome almost always have three instead of the normal two copies of chromosome 21.
They are registered to the IRS under the name Superior Mesenteric Artery Syndrome Research, Awareness and Support, but also work under the DBA of SMAS Patient Assistance. See also
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