A new case of rare erythrocytosis due to EGLN1 mutation with review of the literature

Introduction. - The origin of polycythemia is often simple to detect. Sometimes it is necessary to look for hereditary forms, the decisive parameters being the dosage of erythropoietin and the measurement of the oxygen dissociation curve (P50). These rare diseases are related to high oxygen-affinity haemoglobins, abnormalities of the erythropoietin receptor or dysfunction of the HIF (hypoxia-inducible factor) pathway. Case report. - We report the case of a 56-year-old patient with unexplained polycythemia associated with normal serum erythropoietin and normal P50, in whom the never previously described mutation c.400C>T (p.Gln134*) on exon 1 in the EGLN1 gene (encoding PHD2) was found. Conclusion. - In the face of an unexplained polycythemia a good cooperation between clinicians and biologists is necessary to be able to characterize rare hereditary pathologies. (C) 2020 Societe Nationale Francaise de Meclecine Interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.