Four Subtypes of Autism: A Breakthrough in Understanding the Spectrum

As anyone caring for children with autism would tell you, there are many forms and triggers for this distressingly common condition. Today’s focus article used computer modeling creatively in order to tease out four main subtypes of autism which might allow researchers to better identify both predisposing factors (like genetics) and external contributors to the condition. Without a relevant organization of the problem, pinpointing the genetics that predispose these children to the condition are hard to identify. One of the lead co-authors described the situation as trying to solve a jigsaw puzzle without knowing that 3 or 4 different similar puzzles were mixed in together.

While a few voices still deny the growing rates of autism in our up-and-coming generations, the majority recognize the growing epidemic. Once they see the growing numbers, most want an answer to why it is happening. The age-old debate between nature and nature then arises, with different sides trying to blame either our genes or our environment for the increasing numbers. Those of us keeping our minds open to any possible explanation, have to remind everyone that our genes have not changed that much in the past few decades. While genes do explain some of the cases (especially more severe cases as this study indicated), we have to acknowledge that environmental factors are interacting with these genes and playing a role as well.

As we try to drill down into the “why’s”, the broad variety of autism symptoms has led to the term autism spectrum disorder, as it really is a spectrum of symptoms and severity. Studying the condition then becomes challenging as researchers must decide whether to lump or to split groups. Some autism-diagnosed individuals go about most of life quite functional, even exhibiting impressive intellectual skills and talents, sometimes to the point of considering their autism a gift. Yet, others on a different segment of the spectrum go through life with severe limitations, often requiring significant support from others for daily living. Meanwhile, many go about life with or without a formal diagnosis dealing with varying degrees of life obstacles depending on how much help they get and whether or not they are dealing with other co-morbid mental health diagnoses like ADHD.

These researchers aimed to split the spectrum into a few subgroups that might allow more focused, more effective research into the underlying causes of each subtype. Their computer modeling did draw out 4 main subtypes that I believe we can all acknowledge as ones that we commonly encounter in caring for these individuals. They separated the spectrum into 1) Social and behavioral challenges; 2) Mixed ASD with Developmental Delay; 3) Moderate Challenges; and 4) Broadly affected. These four classes were separable by not only severity of the symptoms and type of autism spectrum symptoms, but also by the further co-morbid diagnoses which more commonly accompanied some of the subgroups.

The first group of social and behavioral challenges included those with the known core autism characteristics who met developmental milestones at a generally normal rate. This group often had the other psychiatric diagnoses and comprised about 37% of the total.

The second group included those with some of the typical autism traits but not as consistent a rate as the first group who tended to reach developmental milestones later than non-affected children. They comprised about 19% of the total.

The third group demonstrated the core autism traits at milder severities and reached developmental milestones on time generally. They, however, did not have as many co-morbid psychiatric diagnoses as the group 1. They were another large group at about 34% of the total.

The fourth and final groups were the more severe cases of autism including more severe developmental delays and social dysfunction. Thankfully these severely affected individuals, who we work with often at the clinic, made up a lower percentage at around 10%.

This new categorization is already helping research as the last group is known to have more ‘de novo’ genetic mutations, meaning a mutation arising the child brand new and not from either parent. These are the more severe cases of autism, which decreases the chance that the genetic mutation will be passed down to another generation.

As these subtypes are better understood and taken into consideration, there is also the hope that subtype differentiation early in life will allow therapies to be targeted for the expected needs of each child rather than treating them all as one autism spectrum group. As research continues, other subtypes are likely to be distinguished from this starting point that further guides etiologic research and therapy research.

From a functional medicine standpoint, we can appreciate this approach to understanding this spectrum as we have been advocating for a variety of forms and causes for autism for decades. We have been treating each child as an “n” of 1 meaning we personalize each child in searching for the triggers underlying their symptoms as well as individualizing their therapies. Still, having categories like this focus article lays out is very helpful, as it means we don’t have to start each patient from scratch in understanding their specific issues. The better we understand broad patterns of autism causes, the better we can identify and care for the individual in our office. Restoring healthier more abundant lives for children with autism spectrum disorder requires us to view them at both the big picture and the minute detail levels.

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Original Article:

Aviya Litman, Natalie Sauerwald, LeeAnne Green Snyder, Jennifer Foss-Feig, Christopher Y. Park, Yun Hao, Ilan Dinstein, Chandra L. Theesfeld, Olga G. Troyanskaya. Decomposition of phenotypic heterogeneity in autism reveals underlying genetic programs. Nature Genetics, 2025; 57 (7): 1611 DOI: 10.1038/s41588-025-02224-z

Thanks to Science Daily:

Princeton University, Engineering School. "Four hidden types of autism revealed — and each tells a different genetic story." ScienceDaily. ScienceDaily, 24 July 2025. <www.sciencedaily.com/releases/2025/07/250724040455.htm>