FAQ

Autism is a complex neurodevelopmental disorder associated with difficulties in social interaction, verbal and nonverbal communication, and repetitive behaviors or interests. It is part of a group of disorders called autism spectrum disorders (ASD), so named because impairments range from mild to severe and vary with each individual.

Disorders also include Pervasive Developmental Disorder not otherwise specified (PDD-NOS), Asperger’s Syndrome, Rett Syndrome, and Childhood Disintegrative Disorder.

Autism statistics from the U.S. Centers for Disease Control and Prevention (CDC) identify around 1 in 88 American children as on the autism spectrum–a ten-fold increase in prevalence over the last 40 years. Careful research shows that this increase is only partly explained by improved diagnosis and awareness. Studies also show that autism is four to five times more common among boys than girls. An estimated 1 out of 54 boys and 1 in 252 girls are diagnosed with autism in the United States.

There is no one cause of autism just as there is no one type of autism. Over the last five years, scientists have identified a number of rare gene changes, or mutations, associated with autism. Research has identified more than a hundred autism risk genes. In around 15 percent of cases, a specific genetic cause of a person’s autism can be identified. However, most cases involve a complex and variable combination of genetic risk and environmental factors that influence early brain development.

Many studies have been conducted to determine if a link exists between immunization and increased prevalence of autism, with particular attention to the measles-mumps-rubella (MMR) vaccine and vaccines containing the preservative thimerosal. These studies have found no link between vaccines and autism.