Polycythemia VeraBudd-Chiari SyndromeRadiology, InterventionalPortasystemic Shunt, Transjugular IntrahepaticPolycythemiaThrombocythemia, EssentialJanus Kinase 2Primary MyelofibrosisMyeloproliferative DisordersSyringomyeliaPipobromanThrombocytosisSyndromeForamen MagnumErythroid Precursor CellsAloeErythropoietinPhlebotomyReceptors, ThrombopoietinErythropoiesisEncephalocelePlatybasiaGranulocytesCranial Fossa, PosteriorReceptors, ErythropoietinThrombosisHydroxyureaBloodlettingHematocritMutationMeningomyeloceleMutation, MissenseHematopoiesis, ExtramedullaryErythroid CellsAmino Acid SubstitutionGPI-Linked ProteinsPlatelet CountDecompression, SurgicalMegakaryocytesColony-Forming Units AssaySubarachnoid SpaceDecompressive CraniectomyIsoantigensHomozygoteChromosomes, Human, 19-20Bone MarrowLeukemia, Myeloid, Chronic, Atypical, BCR-ABL NegativeThrombopoietinSplenomegalyHematopoietic Stem CellsDown SyndromePelvic BonesSpinal CanalCerebrospinal Fluid PressureMetabolic Syndrome X