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Is Autism Genetic?

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Updated December 23, 2010

What Are Genes?

Genes are often described as the "blueprints for life." 30-50,000 genes make up human DNA -- the molecules which tell our bodies and minds how to grow, how to work, how to handle disease, and much more.

Despite the fact that scientists have "mapped" the entire human genome (that is, described and cataloged each gene), we are still very much in the dark as to how genes work. Which gene is responsible for humor? For the capacity to love? Or are these traits truly genetic at all? Questions like these are still very much up in the air.

Is Autism Genetic?

We know for sure that autism runs in families. Siblings of autistic people are more likely to be autistic, and twins are extremely likely to share autistic traits. This means there is almost certainly a genetic component to autism.

But that doesn't necessarily mean that a single gene is responsible, or that inherited genes are the only risk factor for autism. In many cases, genetic anomalies associated with autism are not inherited, but are considered to be "spontaneous mutations." In addition, many researchers believe that a combination of several genetic differences, PLUS some form of environmental "insult," may lead to autism.

Many Autisms, Many Genes?

Even more confusing, many researchers believe that different autistic people can trace their autism to different causes. That's because, as a "spectrum disorder," autism can present with such very different symptoms.

Some people with autism have co-existing conditions such as epilepsy, mental illness (bi-polar disorder is fairly common among autistic people), gastrointestinal issues and sleep disorders. Others have no such conditions, but do present with sensory sensitivities. Yet others are hyperactive.

Dr. Lisa Croen, a researcher at Kaiser Permanente in Oakland, California, has conducted dozens of autism studies. She suggests that people think about autism as "many concentric circles" of symptoms. It's possible that many different genes are implicated in autism -- and that different sets of genes may be implicated for different autistic people.

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