Autism may result from a faulty chemical switch that doesn't get flipped in time to help the brain develop normally, a new research study suggests.
Building on what they hope will be an important insight into the cause of autism, French researchers are testing a high blood pressure medication on dozens of European children with autism.
The team, which has a financial stake in the drug, has tried it on 30 children with autism; now they are testing it in more, hoping to improve core characteristics of autism for the first time.
There are drugs to treat some of autism's symptoms, but none that address the underlying social and communication difficulties and repetitive behaviors, which define the condition. Previous attempts to develop an effective drug against the condition, which affects at least one in 88 U.S. schoolchildren, have either failed or are also still experimental.
In a study out today in the journal Science, the researchers offer an explanation for the promise of their drug, bumetanide, a generic diuretic long used to treat the fluid retention of high blood pressure.
The researchers found that the drug, given during pregnancy, could reverse autism symptoms in newborn mice bred with a genetic condition that often causes autism in people, and in rats exposed to the epilepsy drug valproic acid, which is known to trigger autism.
They suspect that bumetanide is flipping a chemical switch in the brain — changing the chemical GABA from stimulating electrical activity in the brain to tamping it down. This switch needs to be flipped during or near birth for the brain to develop normally, says lead researcher Yehezkel Ben-Ari of the French Institut National de la Santé et de la Recherche Médicale, in Marseilles, France.
Because this switch fails to flip in rodents with two very different triggers of autism, the researchers say they may have found an underlying cause of the condition.
That is a "pretty incredible finding and really great," says Andrew Zimmerman, a pediatric neurologist and autism expert at the University of Massachusetts Medical School in Worcester, Mass.
He and other researchers note that it's too early for people to try the drug outside of carefully watched clinical trials. There are just so many unknowns, from what the drug will do to the developing brain to how much of the drug to give and when.
"So many things cure cancer in mice and rats, and so many things cure all kinds of things and then when we give them to humans they have adverse affects and don't fix the problems we thought they could fix," says Gary Goldstein, president and CEO of the Kennedy Krieger Institute, a Baltimore-based clinic and research center. "I wouldn't give it to my child, I can tell you that."
Ben-Ari and his colleagues have patented a version of bumetanide and formed a company, Neurochlore, in Marseilles, to test the drug in children. He says bumetanide should not be given to pregnant women — despite his success with rodents — because it is impossible to determine which children will go on to develop autism and unethical to test on healthy ones.
It should be used as early in childhood as possible, Ben-Ari says, and his team is testing the drug in children as young as 2. Autism is typically diagnosed around age 4, but experts are working to push that diagnosis earlier. It is widely believed that the sooner treatment begins, the more effective it is likely to be.
Ben-Ari says he is hopeful that the drug will show benefits across a broad spectrum of children with autism, but behavioral therapy and possibly other pharmaceutical treatments will likely still be needed, too, he says.
"It's important for people to understand there is no drug to cure a medical disease as complicated as autism," he says.
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