Tuesday, October 17, 2017

Mice Provide Insight into Genetics of Autism Spectrum Disorders

Studies done on the brains of mice showed a direct link to autism spectrum disorder.  More specifically, a mutation on the CHD8 gene in the cortex of mice brains lead to an increased size of the brain (megalencephaly).  This condition was also present in people with autism spectrum disorder. Research lead by Alex Nord, assistant professor of neurobiology, physiology, and behavior with the Center for Neuroscience at the University of California, performed studies to show the link between genetics and autism spectrum disorder (ASD).  The Nord laboratory strived to show how the "genome of the brain encodes brain development and function."  People with autism spectrum disorder have been shown a mutated gene called the CHD8 gene in their brain.  This gene encodes for protein that is responsible for packaging DNA into the cells.  If the packaging of DNA is altered, it can lead to disorders because it ultimately controls when genes are turned on and off during development.  And so, if the CHD8 gene is mutated it may not tell the proper genes to turn on and off during development, leading to disorders.  However, with the help of studies done on mice brains the genetic link to ASD is becoming more clear.  These studies done on mice were classified as behavioral tests.  Nord and his researchers induced mutation in mice on the CHD8 gene and noticed that they experienced cognitive impairment and increased brain size (megalencephaly).  After analyzing this data, the researchers found that the expression of the CHD8 gene peaks during the early stages of brain development, which in turn lead to an excess of dividing cells during development as well.  Nord also noticed that the changes in gene expression continued throughout the mice's lifetime, suggesting that the CHD8 gene plays a role in biological processes throughout the mice's entire life.  The research done by Nord and his fellow researchers at The Nord Laboratory provides evidence for the genetic link of the CHD8 gene and autism spectrum disorder.  

This picture is of the cortex in the brains of mice; the colored areas represent different layers of the developing cortex. 
I found the study described in this article very interesting.  I have heard of autism spectrum disorder in the past and have encountered individuals with this disorder, however I was not entirely certain on the cause of this disorder.  After reading this article, I was intrigued.  It was interesting to learn that a single mutated gene caused such a spiraling effect in the mice, which then showed a parallel in humans with ASD.  I do believe this was a pivotal start to discovering an effective treatment to autism spectrum disorder.  

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