Two Hypoxia Sensor Genes and Their Association with Symptoms of Acute Mountain Sickness in Sherpas

Introduction: Hypoxia-inducible factor (HIF) and von Hippel-Lindau tumor suppressor protein (VHL) are hypoxia sensors that control cellular responses to hypoxia. Although many Sherpas live at high altitudes for their entire lives, some of them manifest symptoms of acute mountain sickness (AMS) during mountaineering at extremely high altitudes. We hypothesize that the two hypoxia sensor genes might associate with the occurrence of AMS symptoms in Sherpas at extremely high altitude. Methods: In a village at an altitude of 3440 m, 104 Sherpas who had mountaineered at extremely high altitudes (over 5000 m were divided into two groups: Sherpas with (N = 45) and without (N = 59) histories of AMS symptoms.The rs 11549465 SNP in the HIF-1 alpha gene (HIF1A) and the rs28940298, rs779805, rs779808, rs 1678607, and 1149A > G SNPs in the VHL gene (VHL) were identified in the two Sherpa groups using PCR following RFLP. Results: There were no significant differences in either the genotype distributions or the allele frequencies of the HIF1A and VHL genetic variants between the two Sherpa groups. Conclusion: These genetic variants of HIF1A and VHL are not associated with AMS symptoms that occur in Sherpas at extremely high altitudes. It seems unlikely that HIF1A and VHL are associated with hypoxic sensing sensitivity in Sherpas.