Down Syndrome Vs Autism: Differences And Similarities

down syndrome vs autism

Do you also use the terms down syndrome and autism alternately?

Despite having some similar symptoms, it is important to understand the difference between Down syndrome vs autism and learn about their differences and similarities.

Doctors have evaluated many children with down syndrome and autism and sometimes either of them. They have observed that every child has its own strength and weakness and different personality. If you are curious to know more about Down syndrome vs autism, stick to the end of the article then.

A. Down Syndrome vs Autism: Autistic Spectrum Disorder

Autism spectrum disorder is a disorder that is associated with brain development and how a person interacts and socializes with others. Symptoms can include poor communication skills and repetitive behaviours.

The conditions in autistic spectrum disorder are autism, Asperger syndrome, childhood disintegrative disorder, and an unspecified form of pervasive developmental disorder or atypical autism.

Autistic spectrum disorder is detected in young children and it can cause deficits in social relatedness, especially in school and work.

Children within the age of 1 showcase symptoms of autism spectrum disorder. A small percentage of children show no autistic symptoms in the first year and develop later by 18 -24 months.

Till now there is no cure for autism spectrum disorder although early intervention through intensive behavioural treatment can bring some change in the affected.

B. Down Syndrome vs Autism: Intellectual disability

Autism diagnosis in various children can show different patterns of behaviours and levels of severity. It could range from low functioning to high functioning.

Some children have early signs like reduced eye contact and no response to their names by their caregivers. However, some children might develop normally and by the age of 2, show signs of autism.

Some children can have a learning disability and can show signs of intellectual disability. Whereas some autistic children will be intellectually capable but will have repetitive behaviour problems.

They will experience difficulties in social interaction such as having poor language skills and adjusting to social situations. Due to various symptoms in each child, it can be difficult to diagnose. It can be diagnosed based on the level of impairments and how they affect the functioning ability.

To know more about research on autism click here.

C. Down Syndrome vs Autism: Autism Behavior Checklist

An autistic child will showcase these repetitive behaviours such as:

  • They can have repetitive motor behaviors such as the use of objects or speech.
  • Repetitive body movements such as rocking, and spinning repetitively.
  • They could also perform activities that cause self-harm such as biting or headbanging.
  • They could be clumsy or keep their body stiff or have very unusual body movements.
  • They can be absorbed or fixated on an object or an activity and will focus on it for a very long duration of time.
  • They can be sensitive to light, sound, touch, temperature, and pain.
  • Autistic children can be very fussy regarding food and they can be eating only a few foods or refuse foods with a certain ingredient.

As they grow up, Autistic children learn to live in society and showcase few behavioural problems. Most children who grow up can lead normal or near-normal lives but continue to face difficulty with spoken language or social interaction.

D. Down Syndrome vs Autism: Autistic Disorder and Social Interaction

down syndrome vs autism
Image source: Photo by Mikhail Nilov from Pexels

  • They will not show any interest or point at objects
  • They will not look at objects when someone points at it
  • They will be disinterested when other children or other parents are around.
  • They will avoid eye contact
  • They will not regard others’ feelings or pay attention to it.
  • They will not pay attention when people are talking to them whereas pay attention to background noise.
  • They will repeat words or phrases and repeat actions
  • It can be difficult for them to express their needs by using words or motions
  • They can find it difficult to adapt to routine changes
  • They could lose the skills they once had such as stopping repeating words
  • They could have unusual reactions to taste, smell, look, feel or sound.

E. Down Syndrome vs Autism: Down Syndrome

Down syndrome is a genetic condition that occurs in a child when there is an abnormal cell division and it causes the child to have extra chromosomes. Generally a baby is born with 46 chromosomes but children with down syndrome have one extra chromosome 21.

It can also be called Trisomy 21. Down syndrome can also be called a trisomy. The extra chromosome affects the baby’s body and brain development and can result in mental and physical disabilities. Down syndrome can cause intellectual disability and developmental disabilities.

down syndrome vs autism
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Down Syndrome vs Autism: Symptoms of Down syndrome

Children with down syndrome with have these physical features such as:

  • short height
  • short neck
  • bulging tongue
  • small ears
  • flattened face
  • small head
  • short neck
  • poor motor skills
  • short fingers
  • small hands and feet
  • minute white spots in the iris of the eye
  • Upward slanting eyelids (palpebral fissures)
  • Unusually shaped or small ears

Children with Down syndrome are usually born an average size but eventually develop slowly compared to other children. The possibility of a baby having down syndrome can be found during the pregnancy screening. Also, an expecting mother won’t have any symptoms of carrying a child with Down syndrome.

F. Down Syndrome vs Autism: Cognitive Disability

Children with down syndrome to some degree have their cognitive development impaired. They could have mental retardation and intellectual disabilities such as:

  • poor judgment
  • Short attention span
  • poor language skills
  • slow learning disability

Mental and social development delays may mean that the child could have down syndrome.

Medical problems that affect children with Down Syndrome are :

  • Congenital heart disease
  • Eye diseases
  • Leukemia
  • Ear infections
  • Sleep apnea, a medical condition where the person’s breathing temporarily stops while asleep
  • Chronic constipation
  • Obesity
  • Hypothyroidism
  • Dementia
  • Alzheimer’s disease
  • late tooth growth
  • Skin infections
  • Respiratory problems
  • Urinary tract infections

down syndrome vs autism
image source: Photo by Mikhail Nilov from Pexels

G. Down Syndrome vs Autism: Dual diagnosis

A child suffering from Down syndrome could also be diagnosed with autistic spectrum disorder, which is also called a dual diagnosis.

Children with Down syndrome having Autism Spectrum Disorder (DS-ASD) can be challenging, but a better understanding of DS-ASD opens doors to resources and support that will benefit children and families alike.

Children with Down syndrome could have other diagnoses however dual diagnoses are always used to refer to autism. Diagnosing DS ASD could help families to have access to medication and behavioural treatment like communication skills training and Applied Behavioral Analysis (ABA ) therapy.

It will help in decreasing disruptive and behavioural issues like sleep disturbances, aggression, irritability, anxiety, hyperactivity, and poor attention.

H. Down Syndrome vs Autism: Medical Issues

According to the National Down Syndrome Syndrome Society, children with dual diagnoses could be suffering from hidden medical problems like headache, toothache, sinusitis, gastritis, ulcer, pelvic pain, glaucoma, Congenital heart disease, dysfunctional swallow, severe hypotonia, motor delay, respiratory problems and so on.

The outcome will be seen in behaviours that may seem to be common in autistic spectrum disorders such as self-injury and aggressive changes in the child’s behaviour.

It is critical that early intervention be initiated and children with dual diagnoses go through an extensive medical examination so that any underlying medical conditions are ruled out that may affect their early development.

I. Conclusion

Due to the incomplete documentation of cases, the estimation of children with autistic spectrum disorders and Down syndrome can be difficult. Estimates vary between 1 and 10 percent. It is substantially higher than seen in the general population and comparatively less in children with mental retardation.

The causes of autism spectrum disorders are not very well analyzed however upon the observance of the symptoms mentioned above, medical treatment should be sought immediately. Early diagnosis helps in proper treatment and security of normal life for the affected.


While at times contributed by guest authors, our content is medically reviewed periodically by professionals for accuracy and relevance. We pride ourselves on our high-quality content and strive towards offering expertise while being authoritative. Our reviewers include doctors, nurses, mental health professionals, and even medical students. 

Do note that any information found on the site does not constitute legal or medical advice. Should you face health issues, please visit your doctor to get yourself diagnosed. Icy Health offers expert opinions and advice for informational purposes only. This is not a substitute for professional medical advice.


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