Too Many Connections in Brain May Explain Autism Learning Disability... By: Deborah Huso

Researchers from the University of California have discovered that autistic children carrying a common autism risk gene show greater brain connections in the frontal lobe when compared with non-autistic children who do not carry the risk gene.

The study, published in the journal Science Translational Medicine, also showed that this increased brain connectivity in the frontal lobe was associated with fewer connections to other parts of the brain, leading researchers to believe that this latest risk gene may be responsible for "rewiring" of the brain.

The gene variant known as CNTNAP2 was also present in some of the non-autistic children in the study, and those children showed greater activity in the frontal lobe with weaker connections from there to other parts of the brain as well. But those kids did not have autism, meaning that this single gene variant is likely not responsible for the disease itself.

"We have known for some time that in most cases a single gene is not causative for autism," one of the study authors, Dr. Susan Bookheimer, professor of cognitive neurosciences at the University of California, told AOL Health. "These risk genes are fairly common." She says autism is caused by a variety of factors, including other gene variants, gene-to-gene interactions, as well as environmental factors.

"The major finding here is in finding a direct link between a gene and the functioning brain in autism," adds Bookheimer. "Another way to think of it is that genes such as this may bias the brain towards a certain mode of information processing--local processing at the cost of long-range interaction and connectivity that we see in autism."

Dr. Isabelle Rapin, professor of neurology and pediatrics at Albert Einstein College of Medicine and a member of the American Academy of Neurology, did not participate in this latest research but is intrigued by the findings. "Autism has multiple causes," she told AOL Health, "and any papers that show another gene related to autism are helpful." She is quick to add, however, that parents of autistic children shouldn't get too excited about this latest study. "It's premature to say it will be useful in diagnosis or treatment."

Dr. Tom Frazier, director of research at the Cleveland Clinic Center for Autism, agrees, noting that the study would have to be repeated using far more subjects, but he told AOL Health he'll be interested to see if this brain abnormality is specific to autism. "Anytime you find a gene variant associated with a condition, you want to know if it's a modifier or a cause," he added. "In this case, I think they've identified a modifier."

Study author Bookheimer is hopeful her team's research will lead to more promising outcomes in the future. "The primary goal here is not diagnosis but rather understanding mechanisms that cause autism," she says. "It is possible in the future we will be able to identify a collection of genes which together lead to severe enough connectivity deficits to cause autism."     This article from AOL.com is by: Deborah Huso

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