Polycythemia VeraPolycythemiaThrombocythemia, EssentialJanus Kinase 2Primary MyelofibrosisMyeloproliferative DisordersPipobromanThrombocytosisErythroid Precursor CellsAloeErythropoietinPhlebotomyReceptors, ThrombopoietinErythropoiesisHeadacheGranulocytesReceptors, ErythropoietinThrombosisHydroxyureaBloodlettingHematocritFatigueRetrospective StudiesPruritusMutation, MissenseHematopoiesis, ExtramedullaryMutationErythroid CellsAmino Acid SubstitutionGPI-Linked ProteinsPlatelet CountMegakaryocytesColony-Forming Units AssayBudd-Chiari SyndromePainTreatment OutcomeIsoantigensDyspneaCoughLeukemia, Myeloid, Chronic, Atypical, BCR-ABL NegativeChromosomes, Human, 19-20ThrombopoietinBone MarrowHomozygoteFollow-Up StudiesSplenomegalyHematopoietic Stem Cells