Polycythemia VeraPolycythemiaThrombocythemia, EssentialJanus Kinase 2Primary MyelofibrosisMyeloproliferative DisordersThrombocytosisPipobromanErythroid Precursor CellsErythropoietinMutationMutation, MissensePhlebotomyPoint MutationErythropoiesisReceptors, ThrombopoietinReceptors, ErythropoietinHematocritAloeGranulocytesBloodlettingAmino Acid SubstitutionThrombosisHomozygoteHydroxyureaHematopoiesis, ExtramedullaryDNA Mutational AnalysisHeterozygoteVon Hippel-Lindau Tumor Suppressor ProteinGPI-Linked ProteinsExonsErythroid CellsPlatelet CountPedigreeIsoantigensColony-Forming Units AssayMegakaryocytesErythrocyte VolumeBudd-Chiari SyndromeBone MarrowRussiaSomatostatinomaFrameshift MutationPolymerase Chain ReactionLeukemia, Myeloid, Chronic, Atypical, BCR-ABL NegativeChromosomes, Human, 19-20ThrombopoietinHematopoietic Stem CellsLeukocytosisPhenotypeBase SequenceSplenomegalyAlleles