Autism is a rare syndrome that affects an individual's social interactions and communication skills.
This lifelong developmental disability is estimated to occur in approximately one in 1,000 births. It is more commonly found in males than females at a ratio of 4 to 1. Autistic behaviors typically begin appearing between the ages of 18 months and three years of age. Children with autism can demonstrate a wide variety of behaviors. All of the characteristics listed below do not need to be present in order for autism to be diagnosed.