Since it was originally described in 1943 by L. Kanner, the concept of autism has changed. Autistic disorder is now recognized as a pervasive developmental disorder diagnosed on the basis of three behaviorally altered domains: social deficits, impaired language and communication, and stereotyped and repetitive behaviors. The prevalence of the autistic disorder according to these criteria has raised to about 0.3%, and the prevalence of the pervasive developmental disorders is estimated between 0.3 and 0.6%. Autism is now considered as an heterogeneous neurodevelopmental syndrome, with genetic and environmental factors contribution.