Direct sequencing analyses were performed on six genes associated with hereditary erythrocytosis [HBB, exon 2 and exon 3 of HBA2, VHL, EGLN1 (previously PHD2), exon 12 of EPAS1 (previously HIF2A), and exons 5-8 of EPOR].
These results suggest a role for Stat5 in regulation of Epo-mediated cell growth and implicate altered kinetics of Epo-induced Jak2 and Stat5 activation in the pathogenesis of familial erythrocytosis associated with this naturally occurring EpoR gene mutation.
The finding of only five disease-causing mutations in our PFCP patient pool of 43 subjects (12%) indicates that EPOR gene mutations are not the major genetic defect associated with PFCP.
Familial erythrocytosis, associated with high haemoglobin levels and low serum erythropoietin (Epo), has been shown to co-segregate with a sequence repeat polymorphism at the 5' region of the erythropoietin receptor (EpoR) in a large Finnish family.
The recently discovered mutations in patients with CMD (V617F and exon 12 of JAK2 gene, MPL gene), and those identified in hereditary erythrocytosis and in hereditary thrombocytosis have improved our ability to discriminate these conditions.
The rs182123615JAK2 variant was described in several contexts including myeloproliferative neoplasms and congenital erythrocytosis and was supposed to be pathogenic.
Primary familial polycythemia: a frameshift mutation in the erythropoietin receptor gene and increased sensitivity of erythroid progenitors to erythropoietin.
Direct sequencing analyses were performed on six genes associated with hereditary erythrocytosis [HBB, exon 2 and exon 3 of HBA2, VHL, EGLN1 (previously PHD2), exon 12 of EPAS1 (previously HIF2A), and exons 5-8 of EPOR].
Recently, a missense mutation [c.950C>G (p.Pro317Arg)] in the prolyl hydroxylase domain protein 2 (PHD2) gene, whose encoded protein has HIF-1alpha as a substrate, provided evidence of the PHD2 role in a case of familial erythrocytosis.