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