Researchers at the University of North Carolina School of Medicine discovered a single genetic mutation that can cause autism. Last December, scientists identified about 1,000 gene mutations linked to autism but how the mutations caused the disorder remained unknown.
UNC associate professor Mark Zylka, Ph.D. and postdoctoral fellow Jason Yi, Ph.D., discovered an enzyme called UBE3A can be switched off when a phosphate is tacked onto it. In normal brain development, this enzyme can be turned on and off but this switch is blocked by the gene mutation in people with autism.
"UBE3A is a protein that targets other proteins for destruction, so it’s like putting a flag on garbage that somebody else will pick up and throw away,” Zylka said. “We found the mutation hyperactivates the enzyme so it can’t be turned on or off, so it's constantly tagging proteins and things are being destroyed throughout the neuron."
Zylka and Yi examined the genes of children with autism and compared them to the genes of their parents who do not have the disorder.
“The enzyme was hyperactive in the child’s cell but not the parents’ cells. All these mutations have been identified in kids with autism, but the ‘how’ is what nobody really understands,” Zylka said. “Our study shows that a mutation can hyperactivate an enzyme and that hyperactivation is increasing the number of spines in the brain, and we know the number of spines in the brain is seen in kids with autism.”
Zylka said they will continue to study how the mutation specifically affects brain abnormalities in people with autism.
The Centers for Disease Control and Prevention identifies 1 in 68 children in the United States with autism spectrum disorder (ASD). In North Carolina, the CDC identifies 1 in 58 children with ASD.
Zylka and Yi’s research was publishedThursday in the journal Cell. Zylka said his lab plans to use the discovery to find medication and therapy that could be used to treat autism patients.