Association of EGLN1 genetic polymorphisms with SpO ₂ responses to acute hypobaric hypoxia in a Japanese cohort

Background: Recent studies have explored various genetic and physiological factors related to high-altitude adaptation in highlander populations. However, the effects of single nucleotide polymorphisms (SNPs), influencing such adaptation, on physiological responses to hypobaric hypoxia have not been examined in lowlanders with lowlander ancestry. Thus, we aimed to investigate the association between SNPs around the EGLN1 genomic region, possibly involved in high-altitude adaptation, and physiological changes to hypobaric hypoxia exposure in a cohort of Japanese lowlanders. Methods: Physiological data were obtained from 46 healthy Japanese male students under different atmospheric pressure conditions (equivalent to sea level and altitudes of 2500 and 4000 m). Genotypes of seven SNPs around EGLN1 were determined in all subjects by PCR-direct sequencing or TaqMan SNP genotyping assay. Results: Results of the association study suggest that percutaneous arterial oxygen saturation (SpO ₂ ) responses of individuals with rs12097901 and rs2790859 alleles, whose frequencies are high in highlander populations (HL alleles), may be susceptible to acute hypobaric hypoxia. SpO ₂ levels of individuals with HL alleles were lower than those of individuals with non-HL alleles. At the same time, the subjects with HL alleles did not appear to have any remarkable hematological or pulmonary features that may counteract the low levels of SpO ₂ . One may hypothesize that the low SpO ₂ levels in HL allele carriers could be a risk factor for acute mountain sickness in Japanese population. Conclusions: Our findings suggest that rs12097901 and rs2790859 genotypes affect SpO ₂ responses and may be associated with the susceptibility to acute hypobaric hypoxia in Japanese population.