We’ve learned a lot about autism over the past decade but for all we’ve learned, much remains a mystery. Now, a new study says extra brain cells may be key factor.
Autism affects one in every 150 children born today in the United States, or about 1 percent of the population. It’s a spectrum of disorders ranging from a profound inability to communicate and mental retardation to relatively mild symptoms such as with Asperger’s syndrome.
As Reuters reports, scientists say “children with autism appear to have too many cells in a key area of the brain needed for communication and emotional development. This may help to explain why young children with autism often develop brains that are larger than normal, researchers say.
That means autism would develop in the womb because the part of the brain where the cells are found, the prefrontal cortex, typically develops during the second trimester of pregnancy.
“We found a really remarkable 67 percent increase in the total number of brain cells in the prefrontal cortex,” said Dr. Eric Courchesne of the University of California San Diego Autism Center of Excellence, whose study appears in the Journal of the American Medical Association. “It’s a part of the brain that’s important for social, emotional and communication functions, and it composes about 25 to 30 percent of the cerebral cortex,” Courchesne tells Reuters.
Several genes that may increase the risk of autism have been identified, but genetics only explain a small percent of cases. Recent studies have also pointed to environmental facts, possibly while in the womb, that could cause autism.
“For years, it’s been a big puzzle from the standpoint of evidence. Where is the evidence that autism has a prenatal origin?” Courchesne said. “For the first time, we have something really solid,” he said. “This really says prenatal life is a very important time to study and mechanisms there will eventually lead to our understanding of how autism comes about,” he said.
Researchers found excess brain cells in each child with autism they studied, Courchesne said. And the brains of the autistic children also weighed more than those of typically developing children of the same age. Courchesne acknowledges the study is small because it’s hard to find brain samples from children with autism.