At what age do symptoms of Asperger's syndrome first appear?

Many of the symptoms of Asperger's syndrome are noticeable within the first two years after birth, although in some cases, symptoms may not become noticeable until the child goes to school. Parents should not be concerned if their infant or toddler shows one or two symptoms because it is common for young children to display at least one of the symptoms of Asperger's syndrome. Symptoms starting to have a serious effect on the child's behavior and development are cause of concern, and should be addressed with the child's physician.