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Autism and Genetics: Tracing the Pathways Between Genes and the Brain
While we try to dedicate this space to keeping track of the most significant advancements in autism research, often it can seem like an endless parade of potential answers. After all, as we’ve discussed at length, scientists remain divided along three areas of focus as it relates to the cause of autism, choosing to focus either on neurology, genetics, or environmental factors.
Of course, there are few scientists who see the answer to their research lying solely in one of the above areas; rather, one popular opinion is autism is most likely the result of a combination of genes and environmental stressors that include air pollution and maternal nutrition.
Another popular theory is that autism is the result of genetic mutations, or errors that occur within DNA. In 2014, scientists undertook the monumental task of sequencing the genomes of several thousand children with autism. As a result, the scientists behind the study uncovered over a thousand particular mutations that involved hundreds of genes, with each of these mutations providing a clue to solve the case of autism.
In reviewing at this research and looking forward towards the future of autism research, Mark Zylka, a professor at the University of North Carolina School of Medicine, has put forth a radical new way to look at the data, eschewing a gene-by-gene approach that would associate each mutation with causation. Instead, he believes that these mutations are representative of a smaller number of “autism pathways.”
Zylka and his team at UNC believe they have figured out the rough outlines of one such pathway, from the tiny genetic glitch on the gene to the physical changes that the glitch causes in the brain. Like many other discoveries, it took advantage of past research while also relying on a modicum of luck and raising a number of questions amongst researchers.
Zylka and the members of his lab, including postdoctoral fellow Jason Yi, study mutations in a gene that codes for an enzyme called UBE3A, which helps clear bits of old proteins from cells. They knew that most patients with Angelman syndrome, a rare neurological disorder, have too little of this enzyme, and they knew that some people with autism have too much.
When the journal Nature published the research last years naming thousands of genetic mutations in patients with autism, Zykla tasked Yi with the project of going through all of the data to see if the any of the mutations occurred on the gene that codes for UBE3A.
What Yi found was a part of the gene that he identified as the phosphorylation site, which codes UBE3A’s on and off switch. While his work was at first rejected for lack of relevance, once the Nature research was released, he was able to identify a genetic mutation that in fact disabled UBE3A’s on/off switch. In further research, scientists were unable to further prove whether the mutation in a child’s cell line came from the DNA of the mother or father, which is important due to the fact that only UBE3A coded by a mother’s DNA is found in brain development.
While research into the genetic pathways is still at the very early stages, the complicated biological approach that Zylka and other researchers are taking is gaining popularity amongst the autism research community in the hopes that it will pave the pathway to finding the cause of autism. While there is still much more waiting to be had, researchers hope that this breakthrough provides families with a sliver of hope for the future.