Growing evidence suggests that a small minority of persons with autism progress to the point where they no longer meet the criteria for a diagnosis of autism spectrum disorder (ASD). Various theories exist as to why this happens. They include the possibility of an initial misdiagnosis, the possibility that some children mature out of certain forms of autism and the possibility that successful treatment can, in some instances, produce outcomes that no longer meet the criteria for an autism diagnosis.
If it's true that the brains of people with autism are actually "wired" differently to those of neurotypical people, it's hard to see how anyone could grow out of it. Some can and do adapt their behaviour over time, to fit in better, but that doesn't mean they aren't autistic any more. It's like when a blind person navigates their way easily round their own home, because they've learnt where everything is. They haven't stopped being blind.