Polycythemia vera (PV) is a clonal myeloproliferative disease characterized by an erythroid dominant trilineage proliferation of hematopoietic precursor cells. PV belongs to the family of chronic myeloproliferative disorders (MPD), which includes hematological diseases that share clinical and biological similarities, such as a hematopoietic stem cell origin: PV, essential thrombocythemia (ET), primary myelofibrosis (PMF), chronic myeloid leukemia (CML), some types of hypereosinophilic syndrome (HES), systemic mast cell disease (SMD) and other rare disorders. Recently, a specific point mutation in the Janus kinase 2 (JAK2) gene was described in a majority of PV patients and thus constitutes a sensitive diagnostic marker for the disease.
