Genetic studies on autism have zeroed in on a small deletion found in patients' chromosome 16, which affects some 27 genes. So to test the link, a research group tinkered with a mouse model to make a similar deletion, and found that the rodents began to respond in much the same way as autistic children, becoming hyperactive, suffering from restless sleep patterns, experiencing a hard time trying to adapt to new environments and demonstrating the same kind of repetitive motions.
In an intriguing aside, almost half the mice worked on died suddenly, leading some of the researchers to hypothesize that they may have accidentally stumbled across a cause of sudden infant death syndrome.
In a related development, a team of investigators at UCLA, meanwhile, has built their own mouse model for autism by taking out the CNTNAP2 gene. The rodents not only adopted many of the same behaviors associated with autism, they also responded to an approved drug used to treat repetitive motions.
Dr. Daniel Geschwind, director of the Center for Autism Research and Treatment at the Semel Institute for Neuroscience and Human Behavior at UCLA, has been exploring the theory that children with a variant of CNTNAP2 have what he calls a "disjointed brain. Their frontal lobe is over-connected to itself and poorly connected to the rest of the brain. Communication with the back of the brain was particularly diminished."
"Our observations are consistent with theories suggesting that autism rewires the brain to reduce long-range connections and boost short-range connections," said Geschwind. "The front of the brain talks mostly with itself. It doesn't communicate as much with other parts of the brain and lacks long-range connections to the back of the brain."
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