[From gene to disease; JAK2 and polycythaemia vera].

The identification of a point mutation in the JAK2 gene in most patients with polycythaemia vera (PV) has led to increased insight into the pathogenesis of the disease. The mutation causes cytokine-independent growth and proliferation of haematopoietic precursor cells, leading to erythrocytosis. The JAK2-V617F mutation is present in 65-97% of PV-patients and, when found, is indicative for the disease. Future research will have to show if the mutated gene can serve as a target for specific, antiproliferative therapy.