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Here’s to understanding why people with autism have anxiety in adolescence

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Using resources from the Autism BrainNet, researchers from UC Davis show specific brain changes in an area called the amygdala in autism.  The amygdala is associated with fear, emotion and anxiety in people with autism.  But because they can look at the brain directly,  the actual number of neurons in the amygdala can be counted not just in one individual, but in over 50 individuals across ages 2 to 50.  This remarkable study showed that too much activity in the amygdala early may lead to impaired function later on.  This could be caused by too many neurons which are present early on in life in people with ASD, and reflected by fewer neurons later on in life.  These difference can only be detected through looking directly at brain tissue.  To learn more, register for the Autism BrainNet at www.takesbrains.org/signup.

Here is a link to the paper:  http://www.pnas.org/content/early/2018/03/19/1801912115.long

Dr. Avino will be answering questions about this paper on a Q&A on April 9, 2018 – please register here:  https://register.gotowebinar.com/register/7051754498195523073

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Loss of skills in autism partially explained

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Is regression a sudden loss of previously acquired skills or is it the gradual decline in a particular area of function?  Using the right tools, both parents and clinicians can document the gaining and loss of skills in different areas, and they agree on what they see.  However, rather than being a single event, regression is slow, starting at around 12 months and showing continual declines through diagnosis.  Thanks to an NIMH day long symposium on the biological causes of regression, scientists got together to discuss this loss of skills on a biological level.  They think that the decline or loss of skills is due to biological events that disrupt the formation of specific brain circuits at critical times in development.  This can be because neurons stop developing, or maybe the brain goes overboard in shaping and pruning back connections.  If you want to see the amazing full day of presentations that aired in 2016, click here:  https://videocast.nih.gov/Summary.asp?file=19500&bhcp=1.  A link to the Ozonoff study described in the podcast is here:  https://www.ncbi.nlm.nih.gov/pubmed/29524310

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Webinar: Investigating gene x environment interactions in “single gene” autisms

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On May 4th, Dr. Janine LaSalle from UC Davis and (the soon to be Dr.) Keith Dunaway presented on recent research investigating the role of environmental factors in individuals with Dup15 Syndrome.  Individuals with a mutation on chromosome 15 are often diagnosed with autism and previously it had been assumed that these individuals were destined to have a diagnosis due to their genetics.  Dr. LaSalle shows that many of the genes in a critical region of chromosome 15 are tied to turning genes on and off via a process called methylation.  Environmental chemicals or other exposures may also work on these genes to turn on or off gene expression epigenetically.  The first half of the webinar reviews crucial ideas in gene x environment interactions and epigenetics, the second half describes experiments using brain tissue of those with Dup15 Syndrome and autism, as well as cell lines, to understand the role of PCBs in gene expression.

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To see differences in the brains of males and females with autism, you have to look at the brains of males and females with autism

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Last month, UC Davis researcher Cyndi Schumann used resources for the Autism BrainNet to look at what causes differences in the rates of diagnosis between males and females.  Consistent with other studies on this topic, males and females don’t show differences in the rates of autism genes, but rather in the way that the brain controls other genes that code for things like neuroinflammation and development.  Clearly more studies are necessary but it is consistent with the Female Protective Effect in autism.  The full text can be found here:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5294827/

And also, there was a study on genital herpes and autism that CNN got totally wrong.

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Narrowing down gene and environment interactions in autism

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With hundreds of genes, thousands of environmental factors, and now sex being variables in determining risk for autism, where should science start?  Over the decades researchers have been able to start narrowing down the combinations based on specific behaviors of interest, genes, and mechanisms which may narrow down which gene, which environmental factor and which sex.  Dr. Sara Schaafsma and Dr. Donald Pfaff from Rockefeller University combined the three, and found that epigenetic changes in an autism risk gene called contact in associated protein like 2 contributed to elevation of risk for autism behaviors following maternal infection.  In other words, being male and having the mutation produced small changes, increased by the environmental factor.  In another separate study, Dr. Keith Dunaway and Dr. Janine LaSalle at UC Davis used brain tissue to look at a rare variant for autism on chromosome 15.  Typically, mutations of this area of the genome are thought to cause autism.  However, the effects of these mutations are also increased when environmental factors are present, leading to more de novo mutations.  These are all examples of scientific breakthroughs that are helping better understand what causes autism.  Even when it looks like one thing, it’s multiple things.