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

Outcome measures for clinical trials and understanding and determining gene x environment interactions have been two (of many) challenging questions for scientists. In the first study, we explain a new study that looks at the feasibility of three potential biomarkers that have the potential to look at presence of a diagnosis as well as effectiveness of an intervention. In the second half, we describe some new research that shows novel approaches to better understand the presence of an environmental factor with genetic influences, or a new method to describe them in different communities. You can read the studies by clicking below:

https://pubmed.ncbi.nlm.nih.gov/36000217/

https://pubmed.ncbi.nlm.nih.gov/35974006/

https://pubmed.ncbi.nlm.nih.gov/35992618/

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/

Thanks to brain tissue research, scientists now know how cells in the amygdala form, connect, and how this changes with age.  But does that explain behavioral or neurological features in autism?  Last week, Dr. Inna Fishman from SDSU examined connections in and out of the amygdala in children and adolescents in autism, in a different study but the same age range as when cellular changes in the amygdala are seen.  Strikingly, the brain connections to regions outside the amygdala follow a similar pattern at a similar time, which may explain functioning, autism severity and anxiety in adolescents with autism.   Also this week, while autism is a spectrum, it’s on a spectrum with other neurodevelopmental disorders like ADHD.  Just like in autism, there are individuals who are not diagnosed with ADHD until adulthood.  But these adults show signs of autism as children.  This is similar to autism, where symptoms are there but may not manifest until later in life.

https://www.ncbi.nlm.nih.gov/pubmed/30274651

https://www.ncbi.nlm.nih.gov/pubmed/30338854