A team from Princeton University and the Simons Foundation set out to answer a crucial question: is autism really one condition, or are there distinct types that look and feel different in each child? They analyzed data from over 5,000 children in the SPARK autism study, examining more than 230 characteristics—from social skills to repetitive behaviors to developmental milestones—rather than hunting for single genes tied to single traits.
Their findings, published in Nature Genetics in July 2024, revealed four clinically distinct autism subtypes, each with its own pattern of strengths, challenges, and underlying genetic differences.
The four subtypes have different trait combinations and outcomes
The researchers identified: Social and Behavioral Challenges; Mixed ASD with Developmental Delay; Moderate Challenges; and Broadly Affected. Each subtype shows a different mix of developmental, medical, behavioral, and psychiatric traits. For example, children in one subtype might struggle primarily with social interaction and repetitive behaviors, while another group may experience developmental delays across multiple areas alongside other health or behavioral concerns. Because each subtype has distinct characteristics, children may develop and progress differently over time.
Genetic testing may become more useful and targeted
Currently, genetic testing explains autism in only about 20% of children diagnosed with the condition—leaving families without clear answers about what's driving their child's autism. By linking each subtype to specific genetic variations and biological pathways, this research creates the foundation for more precise genetic testing. This means future testing could become better at identifying which subtype your child fits, pointing doctors toward the actual biological mechanisms at work rather than generic results.
Earlier, more accurate diagnosis becomes possible
When clinicians can recognize which of the four subtypes a child fits, diagnosis becomes faster and more confident. This matters because earlier diagnosis typically opens doors to earlier intervention—and we know early support makes a real difference. More targeted diagnosis also means families aren't waiting months or years for answers about why their child presents differently from other autistic children they know.
Next steps for parents and clinicians
- Ask your child's pediatrician or developmental specialist whether they're aware of autism subtyping and whether genetic testing might be relevant for your family.
- Keep records of your child's developmental milestones, behavioral patterns, and any medical or psychiatric concerns to share with clinicians—this information helps identify which subtype fits best.
- Watch for updates on genetic testing advances, as this research is early and clinical tools based on these subtypes may take time to become standard practice.