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Researchers have found dozens of new genes that may play a role in causing autism, according to two studies published Wednesday in the medical journal Nature.
Scientists identified 60
genes with a greater than 90% chance of increasing a child's autism
risk. Previous research has yielded only 11 genes that had been
confirmed with this level of certainty.
Though other studies
have shown the importance of genetics in the development of autism,
experts say these new studies zero in on the exact nature of the genetic
mutations that cause the disorder.
The researchers say these genes appear to be clustering around three sets of key biological functions.
The first set focuses on
the development of synapses in the brain, which are responsible for all
kinds of communication between nerves. The second set is responsible for
the creation of genetic instructions, and the third is responsible for
DNA packaging within cells.
Each of these functions
could have an effect on the individual that would cause the traits
commonly associated with autism, according to one of the studies.
Dr. Matthew State,
chairman of the Department of Psychiatry at the University of
California, San Francisco, and co-author of both studies, believes that
the most important thing to take away from the studies is a new
knowledge base. Instead of focusing on environmental factors, he says,
these studies are focusing on what happens inside of the brain.
This kind of genetic
research has been used to treat all kinds of disorders and diseases,
State says, but before now had not been applied to psychiatric
disorders. Similar genetic studies for childhood leukemia took it from
nearly always fatal to a treatable, often curable disease.
"It's the understanding
of biology at that level that's helped treatments for cancer. It's
something we've been missing in psychiatric disorders in general," State
said. "They lay the groundwork for a transformed understanding of the
disorder and hopefully a transformation in how we're able to diagnose
and treat it."
Autism is a complex
disorder, one that has been difficult to treat because it is so poorly
understood. By tapping into the genetic foundation of the disorder,
scientists theorize, it may be possible to provide more personalized
treatment based on a person's own unique gene set.
"I think that if
everybody were to be genotyped when they're diagnosed, the more this is
studied, the more we'll be able to say what the biological causes are
... and we can target your symptoms with more personalized medicine,"
said Dan Smith, senior director of neuroscience at the advocacy
organization Autism Speaks.
In addition to
developing treatments based on a better understanding of the disorder,
the study provides hope for the prevention of autism as well. A portion
of the genes studied were de novo genes: not passed down from either
parent but developed in the egg or sperm shortly before conception.
Further studies could determine what environmental factors cause those
genes to mutate.
"This is going to begin
to give us an opportunity to study the interactions between genes and
environment," State said. "The rate of new mutation increases with age,
specifically fathers, because a lot of these mutations are in sperm."
State is optimistic about the future and what these two studies will contribute.
"The big difference is
that five years ago, we had no idea. When you have no idea, you have no
opportunity to think in a systematic or rational way to develop
treatment," he said. "We can finally say something really concretely
about a large number of genes that contribute to risk."
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