What is Autism?
Autism (sometimes called “classical autism”) is the most common condition in a group of developmental disorders known as the autism spectrum disorders (ASDs).
Autism is characterized by three distinctive behaviors. Autistic children have difficulties with social interaction, display problems with verbal and nonverbal communication, and exhibit repetitive behaviors or narrow, obsessive interests. These behaviors can range in impact from mild to disabling. Autism varies widely in its severity and symptoms and may go unrecognized, especially in mildly affected children or when more debilitating handicaps mask it. Scientists aren’t certain what causes autism, but it’s likely that both genetics and environment play a role.
Source: National Institutes of Health
http://www.ninds.nih.gov/disorders/autism/autism.htm