Primary MyelofibrosisJanus Kinase 2Thrombocythemia, EssentialPolycythemia VeraMyeloproliferative DisordersReceptors, ThrombopoietinSplenomegalyMyelodysplastic-Myeloproliferative DiseasesThrombocytosisSea-Blue Histiocyte SyndromeBone MarrowMegakaryocytesMutationPrognosisKaryotypingPlatelet CountHematopoiesis, ExtramedullaryWorld Health OrganizationMutation, MissenseReticulinSurvival RateDisease ProgressionAmino Acid SubstitutionOsteosclerosis