These genes are thought to be on the seventh and thirteenth chromosome. In 1980 it was found that among 11 families with a father diagnosed with autism more than half of their children were autistic. The apparently normal parents of autistic children had undiagnosed mild symptoms of autism when tested. Early signs of Autism may appear in the first months of life. Autistic infants tend to stray away from other people, avoiding touch and become limp or stiff when picked up or help.
Autistic children dont reach maturation as fast as normal children.
A normal child will point to objects or smile when seeing their mother before the end of their first year, but children with autism develop this behavior much later. These symptoms may go on unnoticed by parents or doctors in infancy, but by the age of two to three it is clear that something is wrong. The Center for Disease Control and Prevention states that one in 500 children in America suffer from autism. Autistic children are unable to recognize themselves or remember things that they have just done. For example, if an autistic child were to show someone a toy of theirs, they would forget they have just showed it and show the toy repeatedly as if they have never presented it before.