The way in which one specific genetic mutation can cause autism was discovered by researchers while studying the development of a rare neurological disorder called Angelman syndrome. Also they say they may have a treatment to reverse it.
The researcher were able to identify with high confidence only about 27 genes that cause autism when mutated. However hundreds more have been identified as potentially causing the condition.
"Genetic studies are showing that there will be about 1,000 genes linked to autism," said Dr. Mark Zylka, an associate professor of cell biology and physiology at the University of North Carolina. "This means you could mutate any one of them and get the disorder. We found how one of these mutations works."
While studying Angelman syndrome researchers noticed mutations near the gene responsible for regulating the enzyme UBE3A, which is important for neural function and brain development. UBE3A imbalance is already thought to be a cause of autism because the genetic mutation is often seen in people with the condition. These mutations are deleted in the case of Angelman Syndrome, but the mutations in autism cause it to be doubled or tripled.
Researchers have found the gene mutation which turns off the switch tightly controlling UBE3A by using an autistic child's lines from the Simons Simplex Collection. The researchers sequenced genes from the child's parents' cell samples, finding the parents did not have the mutation the child did.
"When this child's mutation was introduced into an animal model, we saw all these dendritic spines form on the neurons," Zylka said. "We thought this was a big deal because too many dendritic spines have been linked to autism."
The researchers may also have a way to decrease UBE3A with drugs that control the protein kinase A, said Zylka. Two compounds were seen in the lab to "substantially" reduce the enzyme's activity in neurons. The study is published in Cell