usually they get into set routines & get very very agited if its broken everything has to be in the right place always
From what I know they vary from child to child. In my nephew we noticed that he was sensitive to loud noises, he was very particular with food; throwing up at the sight of certain foods and certain smells. When it came to his speech, he seemed to revert back to when he was one when he babbled and repeated certain sounds. He also didn't interact with other children very well.
This was just my experience, as I said, the symptoms vary and there are different severities of this condition. I hope this helps. All the best.
My young grandson suffers fron Tuberous sclerosis, and has mild autism. He does not give eye contact, and that is how he was diagnosed with autism. He also cannot speak, and gets very aggressive, throws tantrums for no reason, he can hum tunes, but cannot talk, he finds it difficult to concentrate on anything, and has a low attention span.