Erythropoietin receptor and hematological disease

This review will discuss evidence for the role of the erythropoietin (Epo) receptor in the development of erythrocytosis and other hematological disor ders, The possible causative role of mutations of other genes in the pathog enesis of idiopathic erythrocytosis will be considered, Polycythemia vera ( PV) is a myeloproliferative disorder that is caused by an undefined stem ce ll abnormality, characterized by a significant erythrocytosis, leukocytosis , and thrombocytosis. However, erythrocytosis may arise from apparent (or r elative) polycythemia in which the hematocrit is raised due to a low plasma volume. In such cases the red cell mass is normal. A group of disorders wi th increased red cell mass caused by stimulation of erythrocyte production is known as secondary polycythemia, Investigation of such patients may reve al a congenital abnormality such as high affinity hemoglobin or an acquired abnormality caused, for example, by smoking, renal Vascular impairment, or an Epo-producing tumor. Even after thorough examination there remains a co hort of patients for whom no definite cause for the erythrocytosis can be e stablished, A careful clinical history may reveal whether this idiopathic e rythrocytosis is likely to be congenital and/or familial, in which case the term "primary familial and congenital polycythemia" is sometimes applied, Access to a range of laboratory investigations may define the molecular pat hophysiology, We will now discuss how this process can be investigated. (C) 1999 Wiley-Liss, Inc.