Biology of profound and non-profound autism

Scientists have spent a lot of time trying to understand the biology of autism, unfortunately in the past, scientific studies had everyone with autism lumped together in one group and there are so many differences between people with a diagnosis that any features of the diagnosis itself were hard to detect. In the past, researchers grouped those who are cognitively abled with those who have average or superior intellectual disability, those who are able to express themselves verbally with those who cannot, and those who need 24-hour care with those who can live independently. This week, researchers changed that pattern of lumping all the autisms together by using profound autism as a subgroup and as a way to determine differences across autism subgroups. Researchers at @UCSD examined the cell sizes and the brain sizes of individuals with profound autism and compared them to those with non-profound autism. They found the larger the brain cell, the larger the brain size in different areas, and the more profound the autism. There were differences between profound autism, non-profound autism and typically developing controls. This is just a first step in using different classifications of behavior to understand the neurobiology of ASD and link brain function to autism behaviors, leading to more specific support for those across the spectrum.

https://molecularautism.biomedcentral.com/articles/10.1186/s13229-024-00602-8#Sec26

The ASF Year End Review of Science

Just three days before 2024, ASF provides a summary of the the highlights of scientific discoveries and how they have translated into tools families can use. They include ways to speed up diagnosis and reduce waitlists, study of the brains in females and clinical recommendations for helping autistic females at birth, evidence of better practices around intervention and supports, and a review of the numbers of people who have a diagnosis. It isn’t comprehensive and if something was missed, our apologies, but the summary is 20 minutes.

You can read the text here: https://autismsciencefoundation.org/2023-year-end-review/

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

The earliest differences across ASDs

New neurons can be generated in a dish (amazing in itself), and then these neurons can then be studied to examine how they grow, expand, divide and connect. Using this technology, researchers are finding differences in several cell functions in different forms of autism. These differences are in proliferation, which is an increase in the number of cells, as well as the ability of those cells to signal to each other once they are formed. Some autism brains have too many cells, others do not proliferate as quickly as typical developing cells. These things are somewhat dependent on the genetic background which controls head size.

While these different forms of autism all have differences in proliferation, sometimes in different directions, they are all altered, regardless of the genes involved. So, is this one basic biological features that may help identify autism from the earliest points in development? Since they can be studied at any time in life, is this a new biomarker? Should they be used to better understand different subgroups? Much needs to be studied but please listen to this week’s ASF podcast with Dr. Robert Connacher to learn more about the studies going on at Rutgers University to examine this issue.

https://www.sciencedirect.com/science/article/pii/S2213671122002089

How that little amygdala makes a big difference in autism

The amygdala has been shown to be differently sized in autistic people – at first it is too big then it becomes smaller than typically developing people. But how early are these differences seen and does it relate to a diagnosis? The Infant Brain Imaging Study tackled this question in a recent study which compared those who were likely to develop autism at 6 months to those with Fragile X to see if there were differences and if it was specific to autism. Their findings will surprise you and have implications for targeted supports and interventions.

https://pubmed.ncbi.nlm.nih.gov/35331012/

Better ways of subgrouping ASD?

On this week’s podcast, two new studies which explore the concept of subgroups of ASD are described. First, a “genetics-first” approach. Dr. Samuel Chawner at Cardiff University compares autism symptoms in those with copy number variants to those with no known genetic cause and asks: how similar to each other are they and can genetics be a way to subgroup? Second, the UC Davis MIND Institute explores the specificity of a subgroup of ASD based on presence of autoantibodies in mothers. Should there be a mix of the two and how do families interpret these findings? Listen here:

https://pubmed.ncbi.nlm.nih.gov/33384013/

https://pubmed.ncbi.nlm.nih.gov/33483694/