Polycythemia VeraPolycythemiaThrombocythemia, EssentialHydroxyureaJanus Kinase 2Primary MyelofibrosisMyeloproliferative DisordersPipobromanThrombocytosisErythroid Precursor CellsAloeErythropoietinPhlebotomyReceptors, ThrombopoietinErythropoiesisGranulocytesReceptors, ErythropoietinThrombosisBloodlettingHematocritAntisickling AgentsMutationErythroid CellsMutation, MissenseHematopoiesis, ExtramedullaryPlatelet CountAmino Acid SubstitutionGPI-Linked ProteinsColony-Forming Units AssayMegakaryocytesBudd-Chiari SyndromeLeukemia, Myeloid, Chronic, Atypical, BCR-ABL NegativeIsoantigensBone MarrowChromosomes, Human, 19-20ThrombopoietinHomozygoteSplenomegalyHematopoietic Stem Cells