What causes ASDs and is there a treatment?

by CDC

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What Causes ASDs?

It is suspected that there may be multiple causes for ASD due to a complex interaction of genetic and environmental factors. Family studies have shed the most light on the genetic contribution to autism. Studies of twins have shown that in identical twins there is about a 75% rate of both twins having autism, while in non-identical twins this occurs about 3% of the time. The inheritance pattern is complex and suggests that a number of genes are involved.

For the majority of people with ASDs, the cause is not known; however, ASD tends to occur more frequently than expected among individuals who have certain other medical conditions, including Fragile X syndrome, tuberous sclerosis, congenital rubella syndrome, and untreated phenylketonuria (PKU). Some harmful substances ingested during pregnancy also have been associated with an increased risk of autism, specifically, the prescription drug thalidomide.

What are CDC's efforts?

CDC has established a collaborative autism research network to explore potential causes and factors that make it more likely that a child will have autism. Some of the theories being investigated include infection and immune function, hormones and reproductive factors, genetic factors, gastrointestinal factors, socio-demographic factors, and others.

If you would like to learn more about a specific genetic condition that you think could cause an ASD, you can go to the National Library of Medicine's Genetics Home Reference Web site. Information on each genetic condition includes symptoms, how common it is, related genes, treatments, and links to resources where you can learn more about the condition. The Genetics Home Reference also can help you learn more about genetics, including genetic testing, genetic counseling, and gene therapy.

There is no known cure for ASDs. However, early and intensive education can help children grow and learn new skills. The goal of these efforts is to help with the difficult symptoms of an ASD in a child and to improve the child's skills that help him or her talk, interact, play, learn, and care for his or her needs. Medicines can relieve symptoms and be helpful for some people, but structured teaching of skills (often called behavioral intervention) is currently the most effective treatment.

What is CDC doing about ASDs?

Metropolitan Atlanta Developmental Disabilities Surveillance Program (MADDSP)

CDC tracks the number of children with autism spectrum disorders (ASDs) and four other disabilities in a five-county area in metropolitan Atlanta (Georgia) through the Metropolitan Atlanta Developmental Disabilities Surveillance Program (MADDSP).

We are now looking at information on children who had ASDs in 1996. Based on our initial analysis of the information we gathered, 2-3 of every 1,000 children 3-10 years of age in metropolitan Atlanta had an ASD. We will be putting more findings on this Web site in late 2002.

Brick Autism Project

In late 1997, a citizen's group in Brick Township, New Jersey, told the New Jersey Department of Health and Senior Services (DHSS) of their concerns about what seemed to be a larger-than-expected number of children with autism in Brick Township. Because of the complexity of the disorder and the citizens' concern that environmental factors might play a role, the New Jersey DHSS contacted CDC and the Agency for Toxic Substances and Disease Registry (ATSDR) for help. CDC and ATSDR worked together on a project to find out how common ASDs were in Brick Township and to study the possible relationship of environmental factors to ASDs in the community.

Funded Projects including ADDM and CADDRE Networks

CDC funds ASD-related projects in several states. These state projects look at how common ASDs are in children. Some of the projects also study what factors make it more likely that a child will have an ASD. CDC provides technical support to all of the state projects to help them conduct their studies.

About the Author

www.cdc.gov
The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.