T. Ashmore, J. Inman,E. Cross, P. Baugher

Pacific University, Forest Grove, OR

PURPOSE: Acute mountain sickness (AMS) results from exposure to high altitude environments, especially those above 8000 ft. There are few predictors of AMS, and so it is thought that genetic polymorphisms could play a role. Genes that have been implicated in AMS susceptibility include NOS3and EPAS1. NOS3encodes an enzyme that synthesizes nitric oxide, a strong vasodilator whose G/T polymorphism has been implicated in altitude illnesses. EPAS1encodes a transcription factor that regulates hypoxic response, whose C/G polymorphism has also been linked to high altitude illnesses. Therefore, we investigated the association of NOS3and EPAS1polymorphisms with susceptibility to AMS. METHODS: We recruited 184 volunteers at Camp Muir (10,100 ft) in Mt. Rainier National Park. We administered a demographics questionnaire and the Lake Louise AMS score sheet. We also we collected buccal cells from each subject, from which we isolated genomic DNA and genotyped each individual for NOS3and EPAS1polymorphisms. RESULTS: We found that 36.9% of our participants met the criteria for AMS. As expected, our data showed no significant correlation between reported AMS and age, sex, race, weight, height, body mass index, alcohol use or smoking. With regard to NOS3, we found 48.4% of the subjects were found to exhibit the GG genotype, 39.1% the GT genotype, and 12.5 % the TT genotype, and Hardy-Weinberg equilibrium was confirmed (x2= 1.91). However, no significant correlation between GG/GT/TT genotypes and AMS was found (x2= 0.57, p=0.75). Interestingly, we did find an increased representation of the T allele in individuals reporting AMS symptoms (0.33 versus 0.31). However, these data were not significant (x2=0.58, p=0.44). With regard to EPAS1, 100% of our subjects were found to exhibit 2 copies of the EPAS1C SNP. Therefore, no correlation was found between EPAS1 allele frequency and AMS. CONCLUSION: As expected, we report no significant correlation between reported AMS symptoms and age, sex, race, weight, height, body mass index, alcohol use, or smoking. We also report no allelic variation with respect to the EPAS1C SNP in the population tested. Finally, we report an increase in the NOS3T SNP among those subjects with AMS symptoms, although the data were not significant.

Mazamas Mountaineering Organization Research Grant, Pacific Research Institute for Science and Math Summer Research Grant

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