I had the occasion to work with parents of autistic children. These parents had done their research and one component seemed to be that their autistic children had intestinal problems. That could also apply to my grandson but I do not jump to conclusions but most parents felt vaccines were involved. I had the utmost respect for these parents because the only agenda they had was to find out what caused it. My daughter says Adam was fine unti after vaccines around 18 months and other parents noted the same thing. This is not to be dismissed. So they say it is not vaccines. OK, make other suggestions and someone had better get a handle on this because it is becoming more and more common.
The intestinal issues were possibly a result of vagus nerve over stimulation.