Sperm

The title gets you, right? Well, on this week’s #ASFpodcast we report on a new study that examines epigenetic profiles of sperm and how they related to child outcomes. Do some of the marks on bio-dad’s sperm match to those found in kids with ASD? what about genes related to autism? Also, can parents be good proxies of their child’s intellectual ability? For the most part yes, but sometimes they tend to overestimate this ability. This means they are good, but not perfect reporters. How could they be if the child has a severe intellectual disability?

https://pubmed.ncbi.nlm.nih.gov/37097835/

https://pubmed.ncbi.nlm.nih.gov/37100868/

The molecular signature of the autism brain

Is there a specific “signature’ that make the autism brain unique? Can there be a common set of findings that certain gene expression goes up and another go down and where? And is it linked to behavior? This week, Dr. Michael Gandal at University of Pennsylvania (formerly UCLA) explains his recent findings that looks at the largest number of brain tissue samples so far from multiple brain regions to show a common up regulation of immune genes in the brain and a common down regulation of genes which control synapse formation and neuronal communication. It is most pronounced in areas involved in sensory processing of the brain. You can listen to the podcast today and read the whole paper here:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9668748/pdf/41586_2022_Article_5377.pdf

What sperm tells scientists about the origins of ASD

Does autism begin at a diagnosis, or before a diagnosis?  How early do genetics influence outcome?  This podcast explores a new angle to this question using studies in sperm.  One type of major ASD relevant mutation is de-novo mutations, meaning they are seen in the person with ASD but neither biological parent.  So where do they come from?  They may come from germ cells of the embryo of the parent, which forms the sperm and the egg.  Researchers from UCSD looked at mutations in sperm vs. blood in fathers of those with de-novo mutations and found an enrichment of genetic mutations in sperm.  This means the window of susceptibility can include not just things that happen at conception, but before conception.  Below is a graphic taken from a commentary of this study in Nature by Eric Morrow which may be helpful.

 

SPARK it up

You may have heard of SPARK, it is the largest genetics research project in autism spectrum disorders.  But have they found anything?  Yes!  Pam Feliciano of SPARK discusses what the project is, what a pilot study has found, and how the results might help families with ASD.  In addition, a different but complementary study identified new genes associated with autism.  Given that one of them is a target of environmental factors, it’s time to spark up studies looking at gene x environment interactions as well.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6707204/

https://escholarship.org/uc/item/36f811zq

https://www.tandfonline.com/doi/full/10.1080/15592294.2019.1656158

 

Post zygotic mutations in autism: what you need to know

Yes, another type of mutation in autism was revealed this week.  Those that are evident after the sperm and egg meet to form the zygote but still very early, during embryonic development.  Because it occurs after the original zygote is formed, the mutation is not found in every cell or every region of the body, called post-zygotic.  A collaboration of three major genetic consortia studied and collaborated on these types of mutations and revealed that they consist of about 7.5% of all de novo mutations in people with autism.  They affect autism risk genes and selectively target brain regions associated with autism.  Learn more about what this means for family planning and cognitive ability in people with autism.

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

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.

Exploiting genetics to understand environmental risks for autism

On March 13th, Dr. Mark Zylka from UNC gave a 60 minute overview of how researchers are using autism-relevant genetic mutations in cells to start to understand the interactions between genetics and thousands of environmental factors on gene expression.  He pointed out the convergence of pathways in how genes and these environmental factors worked in the brain, and they included:  neuroinflammation, early brain development, turning neurons on and off, and cell signaling.  Dr. Valerie Hu from George Washington University commented on the important impact of these results and perspective from her lab studying epigenetically modified genes, like RORA, which also may be sensitive to common chemicals found in our environment.  The entire webinar, including the questions that they were able to answer from participants, is found here.

Narrowing down gene and environment interactions in autism

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.

And now….the 2016 year end summary of autism science

The year 2016 was eventful for many reasons.  In this 20 minute podcast, we review some of the scientific discoveries that highlighted findings in causes, understanding, and treating ASD.  Featured more this year is studies on the sibling of individuals with ASD, so we are calling 2016 “The Year of the Sibling”  This review includes genetics, gene x environment interactions, diagnosis, the broader autism phenotype, and early interventions and the role of parent-delivered interventions in long term outcome.  It also highlights the important role of studying brain tissue from individuals with autism to better understand people with autism across the lifespan, including those with known causes and unknown causes of ASD.  We hope you find it informative – please send comments to ahalladay@autismsciencefoundation.org

The potential role of epigenetics in the sex differences in autism

On Tuesday November 15th, Tracy Bale from University of Pennsylvania provided an insightful analysis of sex differences in behavioral, physiological and molecular outcomes following prenatal stress.  She outlined the potential epigenetic markers that may lead to resilience in female offspring which has direct implications for autism.  However, prior to Dr. Bale’s presentation, Donna Werling from UCSF briefly outlined the genetic and behavioral data so far about females with autism and why there is a 4:1 ratio in males to females getting a diagnosis.  This webinar is part of the Environmental Epigenetics of Autism Webinar Series co-organized by Autism Science Foundation, Autism Speaks and the Escher Family Fund for Autism.