Jak2 V617F mutation is a G to T somatic mutation at nucleotide 1,849 in exon 14 of JAK2, leading to constitutive activation of signaling pathways downstream of the erythropoietin receptor. It occurs in 95% of patients with polycythemia vera as well as a smaller percentage of patients with other myeloproliferative neoplasms, encodes a constitutively active Janus kinase that upregulates JAK/STAT signal transduction, resulting in unregulated myeloproliferation (erythrocytosis, often with leukocytosis and/or thrombocytosis).
May occur in:
Polycythemia vera (95% of cases) Essential thrombocythemia (50-60% of cases) Primary myelofibrosis (50-60% of cases) Refractory anemia with ringed sideroblasts associated with significant thrombocytosis (50% of cases)
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