This question is suffering of methodological deficiencies, mainly stemming from lack of prior literature research. So here is your homework:

Firstly, please disambiguate, what do you mean by Hypoxia? See https://en.wikipedia.org/wiki/Hypoxia and explain what kind of hypoxia you mean.

Secondly, try to understand the possibly invalid reductionist approach you are proposing, leading to another disambiguation: are there any 'hypoxia genes' or are there genes with variants implicated in causing 'hypoxia', or are you interested in genes which respond to 'hypoxia'? Anyway, which species are we talking?

Thirdly, please forget about proposing solutions like r-packages or database before defining the question properly. It's an XY problem.