Regulation of erythropoietin production in a case of congenital erythropoietin-dependent pure erythrocytosis

Congenital erythrocytosis with increased erythropoietin level

The term "absolute erythrocytosis" denotes a heterogeneous group of disorders characterized by an increased red blood cell mass. The authors describe a 20-month-old girl with absolute erythrocytosis. Erythropoietin levels were found to be extremely increased, although extensive evaluation failed to reveal a cause for such an inappropriate increase. Of interest is also the documentation of spontaneous erythroid colony formation in the patient's bone marrow cultures. Although such a finding is considered typical of polycythemia vera, the diagnostic criteria of this myeloproliferative disorder were not met.

Sequence analysis of the 3' hypoxia-responsive element of the human erythropoietin gene in patients with erythrocytosis

Erythrocytosis arises from a variety of pathogenic mechanisms. We sequenced a 256-bp region 3' to the erythropoietin (Epo) gene which included a 24- to 50-bp minimal hypoxia-responsive element spanning HIF-1- and HNF-4-binding sites in 12 patients with erythrocytosis and 4 normal subjects. Four polymorphisms were found, none of which affected the HIF-1-binding site, although one polymorphism was present in the HNF-4 consensus region. The data indicate that none of these polymorphisms cause erythrocytosis.