For Families > Disorders and Treatments > A-Z Disorder Guide > Autistic Disorder and Asperger's Disorder (Pervasive Developmental Disorders) > Causes

Autistic Disorder and Asperger’s Disorder (Pervasive Developmental Disorders): Causes


These disorders are congenital, which means that something happened to the child before birth to cause the problem. The concordance rate for Autistic Disorder is 91% for identical twins but 0% for fraternal twins. Evidence indicates that the brain structure and chemicals in these children are abnormal, and therefore they do not process information in the usual way, especially in terms of sounds and language. We do know that a parent's behavior does not cause the disorder.