Relier Pairs polycythemia veraVersion en ligne information about thus blood cancer par Kennedy Ellis 1 what do you experience? 2 polycythemai vera 3 the mutation in which gene causes this blood cancer 4 enlarged spleen 5 what does polycythemia cause? 6 drawing blood janus kinase 2 (JAK2) increased number of red blood cells itchiness, headches, dizziness, bleeding/bruising, weakness, fatigue helps fight infection and filter unwanted material and gets bigger when there is too much RBCs heart attack or stroke helps reduce # of RBCs