SAN DIEGO, CA — Research in humans and animal models points to potential biological and genetic mechanisms contributing to the diversity of behaviors seen in autism. The findings were presented at Neuroscience 2022, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health.
Autism, also referred to as autism spectrum disorder, constitutes a diverse group of conditions related to brain development. According to the Centers for Disease Control and Prevention, approximately 1 in 44 children in the U.S. is diagnosed with an autism spectrum disorder, with the diagnosis being four times more common in boys than girls. New research is offering better understanding of how natural genetic variation impacts brain development and gives rise to the spectrum of behaviors associated with autism and may contribute to more individualized approaches for supporting people with autism.
Today’s new findings show that:
- A group of genes that have altered activity in autism are also regulated differently in developing male and female brains, potentially contributing to sex differences in autism symptoms and diagnosis. (Donna Werling, University of Wisconsin-Madison)
- Analyses focused on behavioral and genomic differences between sibling pairs reveal genetic locations that could prove relevant to autism-related social difficulties. (Nathaniel Stockham, Stanford University)
- In humans with autism and mouse models of autism, brain imaging reveals two dominant subtypes characterized by altered communication between brain regions. (Marco Pagani, Istituto Italiano Di Tecnologia)
“Studies like those presented today confirm that autism is driven by sources of genetic variation that naturally exist in the human population,” says Nicola Grissom, an assistant professor of psychology at the University of Minnesota who studies individual and sex differences in motivated behavior and executive function in mouse models. “A better understanding of the genetic components of autism, and appreciation of the neurodiversity occurring naturally among people, may help combat the stigma that still exists around autism.”
This research was supported by national funding agencies including the National Institutes of Health and private funding organizations. Find out more about autism and brain development on BrainFacts.org.
Press Conference Summary
- Autism spectrum disorders are a diverse group of disorders characterized by different genetic variations influencing brain development.
- Natural genetic variability in the human population may lead to the spectrum of behaviors associated with autism diagnosis and contribute to differential rates of diagnosis and symptomology in males and females.
Defining Patterns of Sex-Differential Expression in the Human Cortex During Prenatal Development and the Intersections With Autism Spectrum Disorder
Donna Werling, dwerling@wisc.edu, abstract 176.05
- Researchers analyzed prefrontal cortex tissue, a region of the brain important for complex cognitive functions, from 85 prenatal donors from the BrainVar data set and identified genes with different expression levels and relationships with other genes between males and females.
- The cortices of males and females have largely similar gene expression patterns, but subsets of genes show relatively higher expression in either males or females.
- Genes expressed prenatally at a higher level in the cortex of males than females overlap with a set of genes that are elevated in the autistic brain and involved in immune processes. This suggests that sex-differential regulation of immune-related functions in the developing brain may contribute to the male bias in autism prevalence.
Mapping Autism Spectrum Disorder Behavioral Endophenotypes to Genomic Regions in Thousands of Families
Nathaniel Stockham, stockham@stanford.edu, abstract 176.01
- Researchers studying families with children with autism spectrum disorder created a statistical model that maps clusters of autism-related behaviors to segments of the genome. They applied this model to genomic and behavioral data from nearly 2,000 families from two large autism spectrum disorder cohorts (AGRE/iHART and Simons SPARK).
- In both cohorts, the strongest map by far was between autism-related social interaction difficulties and chromosome 15.
- Mutation in a subsegment of chromosome 15 is also known to cause two rare genetic disorders, Angelman and Prader-Willi Syndromes. Both disorders have considerable behavioral overlap with autism spectrum disorder, suggesting these syndromes could share some molecular mechanisms.
Mapping the Neuroconnectional Landscape in Autism via Cross-Species fMRI
Marco Pagani, marco.pagani@iit.it, abstract 604.08
- Researchers compared patterns of brain activity in 19 mouse models with genetic mutations associated with autism with those obtained in more than 2,000 humans with autism
- In mice, genetic variations associated with autism produced a diverse landscape of changes in brain circuits. Despite this, two dominant patterns of altered brain activity were recognizable: one was characterized by over-communication among brain regions and the other by under-communication
- In line with mouse investigations, researchers found the presence of two dominant groups of individuals with autism showing patterns of brain over- and under-communication, respectively, a finding that was also replicated in an independent collection of human brain scans.
- The two patterns of altered brain activity were linked to the expression of dissociable sets of genes dysregulated in autism. This suggests that the biological bases of the two patterns could be different. The findings support the notion that there is not one unique brain connectivity signature for autism spectrum disorder.