Well, so far, the best information points to autism not being a disease. It isn't something that's a malfunction of normal processes. It's the processes themselves being different at a fundamental level.
In other words, the only way to conceivably "cure" autism would be by preventing it from happening in the first place. And there's just not a way to do that with current technology and knowledge. I'm not even sure if it'll ever be possible.
It's like trying to cure red hair.