Specific polymorphisms of hypoxia-inducible factor-2 alpha (HIF2α), and Egl nine homolog 1 (ENGL1) genes, which are involved in the hypoxia inducible factor-1alpha (HIF-1α) oxygen sensing pathways, have demonstrated either a higher or lower frequency in those that succumb to AMS (Buroker et al., 2012; Yasukochi et al., 2018; Yu et al., 2016; Zhang et al., 2014). The gene discussed is EPAS1; the disease is ablepharon macrostomia syndrome.