Self-Determination-Blog

Down Syndrome vs. Autism: Understanding the Overlap

Written by NeuroNav Self-Determination Specialist | Jul 1, 2025 1:00:00 PM

If you found yourself here, you might be asking, “Are Down syndrome and autism the same?” or “What’s the difference between autism and Down syndrome?” 

When learning about Down syndrome vs. autism spectrum disorder (ASD), it’s important to keep in mind that they each have distinct causes and characteristics. However, both are developmental disabilities that affect communication, learning, and behavior.

Additionally, living with both Down syndrome and autism is often misunderstood. Whether you’re supporting yourself or a loved one, understanding this overlap can make a huge difference in navigating care, resources, and daily quality of life.

Can You Have Autism and Down Syndrome?

The short answer is yes. It can be a case of co-occurring disorders, which simply means that adults with Down syndrome may also be diagnosed with autism at the same time. Research even suggests that up to 18% of people with Down syndrome also meet the criteria for an autism diagnosis.

But if you’re wondering, “Is Down syndrome autism?” the answer is no. They are two separate conditions, but they can potentially influence one another when they coexist. 

Recognizing autism symptoms in individuals with Down syndrome can be tricky because communication and learning differences often overlap. That’s why it’s so important to understand this co-occurrence in order to tailor support strategies for individuals with both diagnoses.

Autism vs. Down Syndrome: Key Differences

Although they can co-exist, Down syndrome and autism are fundamentally different conditions.

What is Down Syndrome?

Down syndrome is a genetic developmental disability caused by the presence of an extra chromosome 21. This extra material affects physical and cognitive development. Common features include:

  • Distinct facial characteristics
  • Intellectual disability, usually mild to moderate
  • Speech and motor delays
  • Congenital heart conditions or other medical concerns

What is Autism?

Autism spectrum disorder (ASD), on the other hand, is a neurodevelopmental condition that impacts how someone communicates, processes information, and interacts with the world. It’s a spectrum because traits can vary widely from person to person. Common characteristics include:

  • Differences in social interaction and communication
  • Repetitive behaviors, interests, and fixations
  • Sensory sensitivities
  • Unique ways of learning and problem-solving

How Autism and Down Syndrome Can Overlap

When someone is living with both Down syndrome and autism, they may experience more complex challenges, but also have some unique strengths.

Co-occurring Down Syndrome and Autism

Here are some signs to look for in adults with Down syndrome and autism:

  • Limited or absent speech
  • Repetitive behaviors or intense focus on routines
  • Greater difficulty with social connection or eye contact
  • Increased sensitivity to noise, textures, or environmental changes

These behaviors may be seen as “difficult,” but it’s all a matter of awareness and communication. Having Down syndrome vs. autism or both impacts how someone lives and connects with others. However, with the right support, individuals can truly thrive.

How To Support Someone with Both Diagnoses

If you’re supporting someone with both Down syndrome and autism, access to tailored therapies, employment support, and community inclusion programs can make a meaningful difference. Other support can look like:

  • Individualized education plans (IEPs)
  • Speech, occupational, and behavioral therapies
  • Person-centered planning and services with an Independent Facilitator (IF)
  • Empowering individuals through California’s Self-Determination Program

It’s good to remember that there are always people, services, and resources ready to walk alongside you or your family member.

Discover More Disability Resources at NeuroNav

If you’re navigating a diagnosis for yourself or a loved one, whether it’s autism, Down syndrome, or both, you don’t have to figure it all out alone. At NeuroNav, we believe that every person deserves support that is as unique as they are.

Our independent facilitation services help individuals and families make the most of California’s Self-Determination Program (SDP) through personalized planning and guidance. Schedule a free consultation today and see how we can help you thrive.