Polycythemia VeraPolycythemiaThrombocythemia, EssentialJanus Kinase 2Primary MyelofibrosisMyeloproliferative DisordersMutationPedigreeDNA Mutational AnalysisPipobromanThrombocytosisPhenotypeErythroid Precursor CellsAloeErythropoietinPhlebotomyReceptors, ThrombopoietinErythropoiesisGranulocytesReceptors, ErythropoietinThrombosisHydroxyureaBloodlettingHematocritMutation, MissenseHematopoiesis, ExtramedullaryErythroid CellsAmino Acid SubstitutionGPI-Linked ProteinsPlatelet CountMegakaryocytesColony-Forming Units AssayBudd-Chiari SyndromeIsoantigensLeukemia, Myeloid, Chronic, Atypical, BCR-ABL NegativeChromosomes, Human, 19-20ThrombopoietinBone MarrowHomozygoteHematopoietic Stem CellsSplenomegaly