Down syndrome and autism are distinct developmental conditions. When they occur together, understanding the individual requires looking at the whole person rather than assuming one diagnosis explains everything.
Down syndrome
Down syndrome is a genetic condition involving an extra copy of chromosome 21. It can affect how a person’s body and brain develop, and people with Down syndrome have a wide range of abilities, strengths, and support needs.
Autism
Autism spectrum disorder is a developmental disability associated with differences in communication, interaction, learning, behavior, and sensory experiences. Autistic people are diverse, and there is no single autism profile.
When both diagnoses are present
A dual diagnosis can help explain needs that might otherwise be overlooked or attributed to only one condition. Communication, sensory processing, routines, behavior, learning, and daily living can look different from person to person.
Support should therefore be individualized. A useful approach is to ask what the person is communicating, what environments help them participate, and what tools or accommodations increase independence and wellbeing.