New study identifies biologically distinct autism subtypes, advancing path to personalized care

July 15, 2025
Strand of DNA

A groundbreaking new study published in Nature Genetics has uncovered four biologically distinct subtypes of autism—each with its own mix of traits, developmental patterns and genetic differences. The findings offer a promising step toward more personalized care and support for autistic people. 

Researchers analyzed data from over 5,000 children in the SPARK autism study. Instead of looking at single traits in isolation, they used a “whole person” approach, grouping children based on their social behaviors, developmental milestones, co-occurring conditions and other traits. 

Their analysis revealed four subtypes:

  • Social and Behavioral Challenges (37%) – Children in this group show core autism traits like social difficulties and repetitive behaviors, but reach developmental milestones like walking and talking on time. They are more likely to have co-occurring conditions such as ADHD, anxiety, depression or OCD. 
  • Moderate Challenges (34%) – This group shows milder core autism traits and tends to reach developmental milestones on time. They typically do not have co-occurring mental health conditions. 
  • Mixed ASD with Developmental Delay (19%) – These children experience delays in early milestones but usually don’t show signs of anxiety or depression. There is variation within this group in terms of how social and repetitive behaviors appear. 
  • Broadly Affected (10%) – The smallest group faces more severe challenges, including developmental delays, communication difficulties, repetitive behaviors and mental health conditions such as anxiety and mood disorders. 

Each group also had distinct genetic patterns, showing that the biology behind autism varies from one subtype to another. For example, the Broadly Affected group had more newly occurring genetic mutations, while the Mixed ASD with Developmental Delay group was more likely to carry inherited variants. 

However, it’s important to note that these subtypes are based on the specific study sample and may not align exactly with national estimates. For instance, while the Broadly Affected group shares similarities with the CDC’s definition of profound autism, the two categories aren’t identical. The lower percentage seen here (10% vs. the CDC’s 27%) likely reflects differences in definitions and the makeup of the study sample. 

Why does it matter? 

“This study shows us that autism isn’t a single condition with a single cause,” said Dr. Andy Shih, Chief Science Officer at Autism Speaks. “It’s a spectrum made up of many different experiences, challenges and underlying biology. By understanding those differences, we can work toward better care that is matched to each person’s unique needs.” 

The findings may help families and clinicians better understand what to expect over time and guide decisions around services, supports and interventions. It’s a key step toward precision medicine in autism, where care is informed by each person’s individual needs and biology. 

Autism Speaks continues to champion research that helps us understand the diversity of the autism spectrum and brings us closer to more tailored, effective supports for autistic people across the lifespan. 

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