EGLN1 and polycythemia: This could suggest a connection between EPAS1, EGLN1, and Hb production, especially based on what we know about Tibetan and Andean populations whose genetic variation in both genes has been implicated in protecting individuals from erythrocytosis/polycythemia, resulting from living at high-altitude (Peng et al. 2017; Peng et al. 2011; Wu and Kayser 2006).