It really does depend on the disability.
I have two friends with majorish disabilities and both have dated. Jess is blind- her last relationship was 6 months and Lucy's got a disease where the muscles on her leg just haven't grown and she's currently with her boyfriend for about threeish months now.
A lot of the time the disabilities people have are not that noticeable, there are plenty of people out there who have learning problems but they are fine everywhere else. Like my sister- she has ADHD and 39345749873498 other learning difficulties, but she is the biggest flirt ever, gets along with everyone and wherever we go she gets at least two boys doing whatever she wants them to do AND SHE IS 10!!
To me honestly I wouldn't want to date someone with a 'syndrome' disability, I would like to hang around someone who could muck around with me, run about and do stupid things with me. Someone who I might not want to take responsibility for- if they needed help sure I'd be there, but I wouldn't want to be carer you know??