Mutations and thrombosis in essential thrombocythemia

Essential thrombocythemia (ET) constitutes one of the three JAK2/MPL/CALR-mutated myeloproliferative neoplasms (MPNs), which also include polycythemia vera (PV) and primary myelofibrosis (PMF)1. ET is defined by clonal thrombocytosis (platelet count ≥450 × 109/L) and characteristic bone marrow megakaryocyte morphology; the clinical phenotype in ET might include leukocytosis, splenomegaly, microvascular symptoms, and thrombohemorrhagic complications1. Most patients with ET enjoy a near-normal life expectancy while disease progression into fibrotic or leukemic transformation is relatively infrequent (<1% in the first 10 years of disease).