Factors That Influence Heterogeity and How

Understanding factors that make each person with autism different has been a challenge, affecting diagnosis, interventions and the way we think about autism in general. Researchers at Istituto Italiano di Tecnologia, Rovereto, Italy, used computers to see how language, intellectual ability, motor and adaptive functioning grouped individuals into different categories. It turns out there are two groups – one group that improves over time and outperforms the other group consistently even in early life. The other group continues to struggle. These factors are not autism-specific, but do influence the creation of these different groups that are different biologically as well as behaviorally. This week’s podcast is an interview with the researchers on what it means for the future of understanding what might help what person at what time in their life.

The publication is open access and includes the model so their findings can be replicated widely: https://molecularautism.biomedcentral.com/articles/10.1186/s13229-024-00613-5

Profound Autism: The first meaningful autism subgroup

Instead of grouping together people with autism based on traditional severity scores, what if groupings were done based on functional outcome? Would this help better understand the broad spectrum of autism and why some people with autism are so different than others? Researchers at the University of Minnesota led by Kyle Sterrett, together with UCLA and UNC utilized a study that followed children with autism in the early 1990’s into their adulthood, in the 2020’s. They created and asked these families a set of questions (included in the manuscript below) to help identify levels of functioning in people with autism. This was done to help them and their families get the right support at right time. They found that these questions could differentiate people with Profound Autism based on things like level of independence and safety concerns. Dr. Sterrett talks with us on this week’s podcast to explain what they did and why it is so important.

https://pubmed.ncbi.nlm.nih.gov/39031157

Breakthrough for those with rare genetic disorders

This week, more on genetics as an influence to an autism diagnosis with a twist: can genetics lead to a specific treatment for core symptoms – across the board? How do you measure such broad symptoms? Our Rett Syndrome family friends and colleagues developed a novel outcome measure to capture what was most important to them, and the FDA approved it for use in a clinical trial. Years later, a new drug was approved that led to a reduction in behaviors associated with Rett Syndrome. Autism can take a lesson from this. In addition, can the genetics of autism be explained by parents with similar phenotypes? This is called assortative mating. The answer is complex.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10450502/pdf/fped-11-1229553.pdf

https://www.nature.com/articles/s41591-023-02398-1

https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/38877467

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

Are new ICD-11 criteria for an autism diagnosis too vague?

In the last version of the Diagnostic and Statistical Manual, the different subtypes of autism were folded into one label: autism spectrum disorder. A similar revision is being made around the International Classification of Diseases, the system the WHO uses across the world to describe autism and provide appropriate reimbursements for services and supports. In this version, the ICD-11, a combination of 300 different presentations of autism are described. A diagnosis can be made if 1 feature of social-communication and 1 feature of repetitive behaviors are documented, with an onset of any time in life. This is causing a lot of confusion in the community, because since the presentations are not specific to autism, it is difficult to provide an accurate diagnosis using the ICD-11. This week we talk to German psychiatrist Inge Kamp-Becker, MD, who outlines what the changes are, and how misdiagnosis can be made and what those consequences might be. Her summary is linked below.

https://www.nature.com/articles/s41380-023-02354-y

Speak now

Those who are minimally verbal or non speaking represent about 25% of those with an autism diagnosis, yet there is really a lack of effective interventions for this group of autistic individuals. It used to be that everyone who was non-speaking was thought to have minimal ability to understand language, since understanding and speaking are so linked in development. However, group at Boston University studied the largest group of non-speaking autistic individuals so far and discovered that about 25% of them understand more language than they can speak, although this ability is still far lower than those who are neurotypical. The other 75% understand about as much as they can communicate verbally. This indicates that in some cases, the ability to understand words and their meaning exceeds the ability to communicate those ideas verbally. Surprise surprise, just like everything autism – there are differences across the spectrum. Thanks to Yanru Chen at Boston University for explaining the study to us.

https://onlinelibrary.wiley.com/doi/10.1002/aur.3079

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/

Contemplating “syndromic autism”

The words “syndromic autism” have been used to describe individuals with autism who also have a rare genetic mutation. Is it time to change those words to something else? Scientists and clinicians Drs. Jacob Vorstman and Steve Scherer from the University of Toronto share recent data in understanding autism, the role of genetic testing in autism in predicting and treating other conditions that someone with autism may have, and why the words “syndromic autism” may need to be updated to describe a subgroup of autism.

https://pubmed.ncbi.nlm.nih.gov/37330697/

Below is the Figure 1 that Dr. Scherer refers to:

Animal models can explain heterogeneity

Just like no two people are the same, no two strains of mice are the same. Using dozens of different strains of mice with and without a genetic mutation associated with autism called CHD8, researchers at University of Southern California showed great variability in the effect of this mutation on behaviors associated with neurodevelopmental disorders. This can reflect the great differences across people with autism and even people with a rare genetic syndrome associated with autism. It isn’t just one gene, it’s the other hundreds of genes that can contribute to susceptibility or resilience to different features of NDDs. One thing this study did not do was overlay environmental factors, which will also significantly influence the variability seen across the different background genetics in these mice.

https://pubmed.ncbi.nlm.nih.gov/36738737/

Genetics does not equal eugenics

Sometimes when the autism community hears the words “genetics research”, it conjures up images of using genetics to eliminate people with autism. In fact, that’s not the goal of genetics research, nor is it even possible. Recently, several new studies were publish which illustrate how genetics can be used to help people understand their diagnosis, and receive more targeted supports. Special guest Jonathan Sebat from UCSD provides perspective on these findings and why genetics research is misunderstood.

https://pubmed.ncbi.nlm.nih.gov/35654973/

https://pubmed.ncbi.nlm.nih.gov/35654974/

https://www.genome.gov/event-calendar/irreducible-subjects-disability-and-genomics-in-the-past-present-and-future