Essential Thrombocythemia is one of several disorders classified as a myeloproliferative neoplasm (MPN). Other MPNs include Chronic Myeloid Leukemia (CML), Polycythemia Vera (PV), Primary Myelofibrosis (MF), Chronic Neutrophilic Leukemia (CNL), Mastocytosis, Chronic Eosinophilic Leukemia, and MPN unclassifiable.
The JAK2-V617F mutation is found in approximately 50% of patients diagnosed with ET. JAK2 is a tyrosine kinase involved in signal transduction for erythropoietin (EPO), thrombopoietin(TPO), granulocyte-colony stimulating factor (G-CSF), and others.
The platelet increase resulting from this mutation can cause microvascular occlusions of the distal extremities, the eye, and the central nervous system. However, not all patients experience these. When the platelet counts become extremely high, thrombocythemia can also lead to deep vein thrombosis and/or bleeding in some patients.
Patients also have a possible risk (although it is quite a low risk) of evolution into another MPN or acute leukemia.
