There are well-defined genetic patterns within the brains of all autism patients, no matter their symptoms, according to scientists who say the finding may help identify a cause and a new way to attack the disease.
The patterns are seen in the way genes are expressed to create proteins in the brain, according to a paper published in the journal Nature. Distinct similarities were found among autistic brains in areas that play a role in judgment, creativity, emotions and speech, the report said. Brains of those without the disease showed different patterns.
Developmental disorders, including autism, have increased 17 percent from 1997 to 2008, according to research published earlier this week. Scientists don’t know what causes autism, although genetics and environment may play roles, according to the National Institutes of Health.
“This finding teaches us that there may be a final common gene activity network from many different mutations,” said Robert Ring, vice president for translational research at Autism Speaks, an advocacy group. “This opens a new target space for thinking about therapeutic intervention.”
The technology to study brain networks in living patients isn’t yet available, so it’s too soon to use as a diagnostic measure, said Ring, who wasn’t an author of the study. Instead, today’s results may spur investigators to look for ways to measure similar gene activity in live people, he said.
Autism is a developmental disorder that appears in the first three years of life, and affects the brain’s normal development of social and communication skills, according to the NIH, based in Bethesda, Maryland. Symptoms may include being withdrawn, communicating with gestures rather than word, touch oversensitivity, repeated body movements and unusual attachments to objects, the health agency said.
Scientists compared brain samples from 19 deceased autism patients and 17 healthy volunteers to measure gene expression levels. The autistic brains studied didn’t have as many genes responsible for neuron communication as normal organs, and they had more DNA involved in immune function, the study found.
“Several of the genes that cropped up in these shared patterns were previously linked to autism,” said Daniel Geschwind, a professor of neurology and psychiatry at the University of California Los Angeles medical school and a study author, in a statement. “We provide evidence that the common molecular changes in neuron function and communication are a cause, not an effect, of the disease.”
In healthy controls, 500 genes varied in expression between the frontal lobe, the control center for judgment, and the temporal lobe, which organizes sensory input, the researchers found. In the autistic brains, there was no difference between these regions.
“The frontal lobe and temporal lobe are both important in other studies,” said Martha Herbert, an assistant professor of neurology at Harvard Medical School, in a telephone interview. “The big step forward is you’re looking at a bigger picture of genetic alteration that also includes not only neurons and synapses but also immune dysfunction, all connected together in context, instead of in isolated details.”
The findings may also help focus research on environmental contributors to autism, and lead to drugs to help autistic patients later on by identifying targets for scientists, she said.
The research team included scientists from the University of Toronto and King’s College London. The brain samples were provided by the Autism Tissue Program, a brain bank registry, the Harvard Brain Bank and the Medical Research Council’s London Brain Bank for Neurodegenerative Disease.
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