What Is It?
Autism is a developmental disorder of the brain. People with autism have problems communicating and interacting socially. They also may have unusual patterns of behavior, interests and activities.
Doctors use the term autism spectrum disorder (ASD). This term includes the five kinds of autism.
The three main types of autism are:
There are also two rare autism disorders:
Signs of autism spectrum disorder are typically first seen before a child's third birthday. However, only half of children with autism are diagnosed before kindergarten.
Rett syndrome appears to be caused by a genetic mutation.
The causes of the other types of autism remain unknown. Various studies suggest that autism may:
Studies have found no link between vaccines and autism.
All types of autism except Rett syndrome are more common in boys than in girls.
Page 1 of 9 Next Page: Autism Symptoms
From Health A-Z, Harvard Health Publications. Copyright 2007 by the President and Fellows of Harvard College. All rights reserved. Written permission is required to reproduce, in any manner, in whole or in part, the material contained herein. To make a reprint request, contact Harvard Health Publications. Used with permission of StayWell.
You can find more great health information on the Harvard Health Publications website.