Someone out there would pay to learn what you know, what you have to do is find those people, and present the information in

a concise, accurate, and attractive way.

You can do that by using Google, and a number of other good sites like:

www.ezines.com

www.overture.com

www.alexa.com

and find out how often that subject is being searched, what competition is out there, what they have to offer.   

It may seem strange, but there are people who are “expert” in the experience of a rare disease  who can teach other people about it.

Make a list of some of the things you know well, or can do well, and start doing some research

 Write something, and submit it to Ezine sites ( do a search on Google ), and you could get published, with a link back to your site and some contact info.