Autism is a syndrome, or condition, with many possible causes.  Anything that makes the central nervous system (CNS) develop abnormally can cause autism.  The CNS functions as a computer for the body.  Messages from the CNS control all aspects of learning, thinking, and movement that allow us to learn about and function in the world.

Any interruption or change in the early development of the system will affect continuing development of the system and result in a developmental disability.  The event that initially triggers these developmental differences could happen during fetal development, during birth, or after birth.  It is not always possible to identify the exact causes of the damage.