Autism Spectrum Disorder Subtypes

​Here’s a refined explanation of the four biologically and clinically distinct subtypes of autism identified by researchers from Princeton University (in collaboration with the Simons Foundation), based on recent genetic and developmental data:
Four Autism Subtypes
​1. Social and Behavioral Challenges
  • Individuals in this category display core autism traits—such as difficulties with social interaction and repetitive behaviors—but typically reach developmental milestones (like walking and talking) on time.
  • They often experience co-occurring conditions like ADHD, anxiety, depression, or OCD.
  • This is the largest group, comprising approximately 37% of the studied sample.
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2. Mixed ASD with Developmental Delay
  • These individuals experience delayed developmental milestones (e.g., walking and speaking), but generally do not display significant psychiatric comorbidities (such as anxiety or depression).
  • There is variability within the group in terms of social challenges and repetitive behaviors.
  • Represents about 19% of the participants.
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3. Moderate Challenges
  • Individuals show milder autism symptoms, reach developmental milestones on schedule, and usually have fewer co-occurring psychiatric conditions.
  • This group makes up around 34% of the sample.
4. Broadly Affected
  • This smallest subgroup (~10%) experiences the most significant and wide-ranging challenges: delays in development, marked social communication issues, repetitive behavior, and co-occurring mental health conditions like anxiety and mood dysregulation.
  • Genetically, this group shows a higher prevalence of de novo (new, non-inherited) mutations, indicating more complex biological heterogeneity.
Why It MattersThese subtypes reflect distinct clinical trajectories and underlying biological profiles, paving the way for precision diagnosis and more tailored supports and interventions.

Sources
  • Princeton University. (2025, July 9). Major autism study uncovers biologically distinct subtypes, paving way for precision. Retrieved from Princeton University website.
  • Autism Speaks. (2025, July 15). New study identifies biologically distinct autism subtypes, advancing path to personalized care. Retrieved from Autism Speaks website.
  • Simons Foundation / Flatiron Institute. (2025, July 9). New study reveals subclasses of autism by linking traits to genetics. Retrieved from Simons Foundation website.