This film didn't ring any bells with me, but a friend is trying to remember it. The details she has are as follows...
"...a woman who lived with her two or three adult sons. She had no legs and lived under her bed on a mechanics board. I am assuming they lived in the Appalachians and were up to no good. Does this sound familiar?"
Never mind, it turned out to be an episode of the X-Files.
one of the best and most disurbing episodes! inbreeders! eewww!