Gender difference update

Girls and boys with autism generally show the same symptoms of ASD overall, but what about different aspects of features? What would happen if you studied girls and boys separately and examined detailed assessments of things like motor skills, repetitive behavior, communication or social interaction? These are where subtle signs of differences between genders is showing up. Girls show a higher age of diagnosis, but that depends on cognitive ability. Also, girls with ASD seem to have superior social interaction skills, which reflects normal gender differences. These differences are magnified over time. A new study also looks at Vitamin D levels during pregnancy and outcome in boys vs. girls…..the results are still unclear but interesting.

https://pubmed.ncbi.nlm.nih.gov/33137209/

https://pubmed.ncbi.nlm.nih.gov/33135392/

https://pubmed.ncbi.nlm.nih.gov/33136459/

Beyond what scientists already know about environmental factors

This week the ASF Podcast explores two ways to better understand the environmental influences in ASD diagnosis: 1. through potential cost savings of avoided cases of ASD due to reduced air pollution and 2. by studying pre-conception exposures going back as far as the grandparents exposure. These two concepts do not prove any one thing, including one environmental factor, causes ASD, however, using these approaches may improve understanding of ASD and allow for legislation that improves many health outcomes in children. Below are the two references:

https://pubmed.ncbi.nlm.nih.gov/32749866/

https://pubmed.ncbi.nlm.nih.gov/32704384/

Age of parents and ASD. It’s complicated.

Questions have loomed around the finding of an increased risk of parents having a child with ASD if they are under 20 or over 35. Of course not every parent who is really young or older will have a child on the spectrum and plenty of those between those ages also have children on the spectrum. Risk factors for ASD are not absolute, they are nuanced and work with other genetic and environmental factors. This week, Kristin Lyall from the AJ Drexel Autism Institute found that those with a strong genetic influence were not as sensitive to factors like parental age. This goes to show, yet again, that it isn’t about ONE risk factor, it’s about dozens working together. And for those 30 year old parents who had a child with autism – see, not every research finding applies to you directly.

https://www.ncbi.nlm.nih.gov/pubmed/32314879

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4521130/

Environmental factors: the forgotten stepchild of autism spectrum disorders

When people hear the word “heritability” in mathematical estimates, they automatically think “just genetics”.  That isn’t true, and this week epidemiologist Brian Lee from Drexel talks us through his SpectrumNews viewpoint about what heritability actually is and why there is room for environment.  Also this week, twin studies, which have traditionally used the word heritability to distinguish genetic vs. environmental interactions, are studied in a new light.  This one shows that severity and differences of autism across the spectrum in identical twins are caused by environmental differences – not just genetics.

https://www.ncbi.nlm.nih.gov/pubmed/31853901

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

 

The Department of Defense and Autism Research

Did you know that in addition to the DoD’s support of the military, they all have funded $65 million in autism research?  This podcast discusses some of their programs and how they support military families and benefit the autism community. Want to read more about what they fund?  There’s a list here:  https://cdmrp.army.mil/search.aspx

What does and does not change the probability of an autism diagnosis

Once again, this week another study  came out dismissing the link between vaccines and autism.  Add this one to the list, but this is one of the largest and takes into account genetic and non-genetic risk factors.  It continues to discredit the vaccine-autism link.  However, in other science, more evidence that prenatal folic acid supplementation, something women should be doing anyway, does reduce the probability of having a second child with autism.  So take your folic acid – either by prescription or over the counter.  As Martha Stewart says, it’s a good thing to do.

https://www.ncbi.nlm.nih.gov/pubmed/30831578

https://www.ncbi.nlm.nih.gov/pubmed/30810722

Genes and Environment, Genes and Environment. Go together like aging and retirement.

Twins with autism, where either one or both is diagnosed, is crucial to understand the role of genetics and the environment to both autism diagnoses and now, autism traits.  In a study this week, researchers using data from the California Twins Study examined the genetic and environmental influences of brain development in multiple regions and measures.  While estimates of genetic and environmental influences can only be modeled in twins, they can be experimentally tested in animal models.  Researchers at the University of Washington investigate what causes the link between air pollution in humans and autism by studying diesel fuel exhaust in pregnant mice.  Finally, across all of these disparate animal studies – does anything pull them together.  Are these models all one-offs or do they have anything in common?  It turns out disruption in normal brain activity is one thing that they have in common, and something that is at the common core of ASD neurobiology.

 

https://www.ncbi.nlm.nih.gov/pubmed/30659287

https://www.ncbi.nlm.nih.gov/pubmed/30668980

https://www.ncbi.nlm.nih.gov/pubmed/30679017

 

Understanding the hard to research

What do Princess Kate and Amy Schumer have in common, and what does it have to do with autism?  The answer:  Hyperemesis Gravidum.  It’s linked to autism, but not strongly, but it does show more evidence of significant overlap between many neuropsychiatric issues and disorders.

More importantly though, those with low verbal ability and low cognitive function are harder to study than most people with autism.  Two new research studies documented what they had to do to make studies in this population possible, and how this group was different from those with average IQ and some words.  One looked at brain structure, and the other was a treatment for minimally verbal girls with autism.

The HG study:  https://www.ncbi.nlm.nih.gov/pubmed/30594672

The minimally verbal girls study https://www.ncbi.nlm.nih.gov/pubmed/30607780 

The imaging study:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6307191/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6307191/