Polycythemia VeraThrombocythemia, EssentialPolycythemiaJanus Kinase 2ThrombocytosisPrimary MyelofibrosisHydroxyureaMyeloproliferative DisordersReceptors, ThrombopoietinPipobromanErythroid Precursor CellsThrombosisPlatelet CountMegakaryocytesAloeGranulocytesErythropoietinThrombopoietinPhlebotomyMutation, MissenseCarbazilquinoneMutationErythropoiesisAmino Acid SubstitutionLeukocytosisLeukemia, Myeloid, Chronic, Atypical, BCR-ABL NegativeSplenomegalyGPI-Linked ProteinsBone MarrowReceptors, ErythropoietinIsoantigensHomozygoteBloodlettingHematocritBlood PlateletsAntisickling AgentsHematopoietic Stem CellsErythroid CellsHematopoiesis, ExtramedullaryPoint MutationLeukemia, Myelogenous, Chronic, BCR-ABL PositivePlatelet Aggregation InhibitorsThrombocytopeniaReceptors, CytokineInterferon-alphaThrombopoiesisDNA Mutational AnalysisColony-Forming Units AssayHeterozygoteErythrocyte InclusionsProto-Oncogene ProteinsHematopoiesisBudd-Chiari SyndromeAnemia, Refractory