Autism spectrum disorder (ASD) affects brain processing related to the senses, social interaction, communication, and behavior. Common symptoms include not responding when called, avoiding eye contact, difficulty playing with others, lack of pretend play or unusual repetitive pretend play, and not enjoying changes in routine. Famous people who are believed to have had ASD include Abraham Lincoln, Albert Einstein, Thomas Edison, Beethoven, Bill Gates, and Charles Darwin. The document provides information about World Autism Awareness Day and symptoms of autism spectrum disorder.