I'm disabled. And when I write my fanfic, I find lot of my interest in disability comes out, but in a sideways fashion. For instance, when I used to write HP fanfic, the main POV character I did was Lupin. I knew it was because of his disability. I empathised.
Even when I wrote other characters, I got told that I sometimes wrote their magical powers as if they were disabilities - well, they are, aren't they? I mean, Harry's aunt certainly sees magic that way. And HP is a wonderful universe to write about disability in, and of all kinds. There are a lot of magical accidents and an equal number of unfair prejudices.
I've moved into another fandom now (The Mighty Boosh). Yeah, I don't think I write so much about disability now.