If there is literature,two places to start would be pubmed ( pubmed.ncbi.nlm.nih.gov) and Google scholar. You may also search for communities where people with the disease hang out-- subreddits, forums, Facebook groups, etc-- and learn about lifestyle and common problems from them. If you know what it is, that just makes it a matter of figuring what type of info it is you desire, and optimizing your search for that. Scihub would also be a good place to look.
One way to easily find good research papers about it, is to go to the Wikipedia page and looking at the citations. They tend to cite the larger summaries, and they'll sometimes be available on pubmed-- if not you may need to look at scihub for the full text. That's a good introduction to the research paper side of information
One thing I've also heard is if your email the author on the research paper, they'll often send it to your for free. While distribution is through expensive journals, researchers can and often want to distribute them freely to intetested parties. Just another alley to search
One way to easily find good research papers about it, is to go to the Wikipedia page and looking at the citations. They tend to cite the larger summaries, and they'll sometimes be available on pubmed-- if not you may need to look at scihub for the full text. That's a good introduction to the research paper side of information
One thing I've also heard is if your email the author on the research paper, they'll often send it to your for free. While distribution is through expensive journals, researchers can and often want to distribute them freely to intetested parties. Just another alley to search