Identification of Two Novel <i>EPOR</i> Gene Variants in Primary Familial Polycythemia: Case Report and Literature Review.

Primary familial and congenital polycythemia is a rare disease characterized by an increase in red cell mass that may be due to pathogenic variants in the EPO receptor (<i>EPOR</i>) gene. To date, 33 genetic variants have been reported to be associated. We analyzed the presence of <i>EPOR</i> variants in two patients with polycythemia in whom <i>JAK2</i> pathogenic variants had been previously discarded. Molecular analysis of the <i>EPOR</i> gene was performed by Sanger sequencing of the coding regions and exon/intron boundaries of exon 8. We performed in vitro culture of erythroid progenitor cells. Segregation studies were done whenever possible. The two patients studied showed hypersensitivity to EPO in in vitro cultures. Analysis of the <i>EPOR</i> gene unveiled two novel pathogenic variants. Genetic testing of asymptomatic relatives could guarantee surveillance and proper management.