Peggy Halliday: Autism is a developmental disorder that affects the functioning of the brain. The Center for Disease Control estimates that today, autism affects 1 in 150 individuals. Autism is characterized by impairments in three broad areas. The first is in social interactions, the second is in communication which includes language, and the third is in behavior. There are other features that are also associated with autism to a lesser or a greater degree in particular individuals and these include things like sensory issues such as taste, touch, texture, light, and noise. There also may be hyperactivity, a short attentions span, tantrum behavior, self-injury or aggression. There may be sleeplessness; all of these characteristics begin before the age of three.
No one knows what causes autism; this is an area of a great amount of research in the medical field today. There are a number of theories that are being checked out but we really don't know what causes autism. We know that researchers agree that there is some kind of genetic link and we know that at least in some children environmental factors probably play a role as well. Whatever the cause is, the likelihood to develop autism is present at a child's birth.