2 is about the age where autism begins to show itself. They all seem normal prior to that because they aren't able to express the signs that would signal autistic behavior.
I did a little looksee through the links, but I didn't see a definite cause. Both my cousin and my almost 18 yr old son had extremely high fevers at age 2. My son has behavioral problems, but is intelligent. He just feels compelled to break every rule. He lives with his father now.
I took him to a lot of doctors, medical and shrinks, but no one could come up with a definite diagnosis. Our long time family physician at the time, told me his problems are genetic.
As a parent, his behavior I hate to say, does make you look bad.