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When it Comes to Down Syndrome vs Autism, What Are Some Similarities?

March 10, 2023

Parents and caregivers of children with diagnosis of down syndrome and autism spectrum disorders, can wonder if these diagnoses can coexist, and when it comes to down syndrome vs autism what should they look for? Although these two conditions can coexist, if parents and/or caregivers have concerns, their child’s doctor has the knowledge and resources in order to answer questions or can point them in the direction of someone who can.

When it Comes to Down Syndrome vs Autism, What Are Some Similarities? https://www.autismparentingmagazine.com/similarities-between-autism-down-syndrome/

In this article, we are going to discuss down syndrome, and autism spectrum disorders, whether there are similarities, and what parents can look for to further support their children and make sure they are receiving the resources and support they can to help them as they develop.

What is Down syndrome?  

When a child is born and has been diagnosed with down syndrome, that means that they have been born with an extra chromosome. Chromosomes are how genes are packaged in the body, determining how a baby is formed and how they will function, physically and mentally, and develop in utero and after birth.

Babies are usually born with 46 chromosomes, whereas a child with down syndrome has the extra chromosome, also called trisomy. Therefore, another term for down syndrome is called Trisomy 21.

Some common characteristics of down syndrome include, but are not limited to:

  • flattening of the nose and face
  • eyes that slant upward and almond-shaped
  • smaller ears
  • shorter neck
  • having a tongue that sticks outside of the mouth
  • smaller hands and feet
  • shorter stature compared to peers

Although there are many similarities between these children with down syndrome, as with any diagnosis, each person is an individual. That means that there will be individual strengths and differences experienced between these people with down syndrome.

Three types of down syndrome

There are three types of down syndrome that can be differentiated through chromosomal testing because each type has its own behaviors and physical traits. According to the Centers for Disease Control and Prevention (CDC), the three types are classified as follows:

  • “Trisomy 21: About 95% of people with Down syndrome have Trisomy 21. With this type of Down syndrome, each cell in the body has 3 separate copies of chromosome 21 instead of the usual 2 copies.
  • Translocation Down syndrome: This type accounts for a small percentage of people with Down syndrome (about 3%). This occurs when an extra part or a whole extra chromosome 21 is present, but it is attached or “trans-located” to a different chromosome rather than being a separate chromosome 21.
  • Mosaic Down syndrome: This type affects about 2% of the people with Down syndrome. Mosaic means mixture or combination. For children with mosaic Down syndrome, some of their cells have 3 copies of chromosome 21, but other cells have the typical two copies of chromosome 21. Children with mosaic Down syndrome may have the same features as other children with Down syndrome. However, they may have fewer features of the condition due to the presence of some (or many) cells with a typical number of chromosomes.”

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What is the possibility of a dual diagnosis and how do parents recognize the signs?

Autism and down syndrome can coexist, and according to the article, Autism Spectrum Disorder in Down Syndrome: Experiences from Caregivers, 5 to thirty-nine percent of children with down syndrome are also diagnosed with autism spectrum disorder. It is important to know the signs and symptoms to have a better understanding of both diagnoses.

Children with down syndrome typically receive a diagnosis earlier in life, sometimes before birth. Whereas, children with co-occurring health conditions, such as down syndrome and autism spectrum disorder typically happens during elementary school age.

This is due to developmental regression that can occur with many autistic children when they are older, versus those children with down syndrome alone.

Some reasons that co-occurring health conditions can go undiagnosed

  • lack of knowledge and awareness of down syndrome and autism spectrum disorders
  • the ability to diagnose and recognize the symptoms of down syndrome and autism spectrum disorder (ASD)

Some similarities between both diagnoses

  • there can be similar needs when it comes to communicating
  • repetitive behaviors
  • some difficulties with social interaction and pretend play
  • challenges with understanding using and reciprocating social cues
  • behavioral differences

The ability to decipher and diagnose both diagnoses can come down to parents and what they see and any questions and concerns that they may have about their child’s behavior and/or development. That is one of the reasons that parents fill out the developmental Ages and Stages assessments that are typically found at Well Child visits for infants and young children in the United States.

An early diagnosis can make all the difference

Family members can help parents and caregivers with diagnosis because they can keep the conversation open and discuss any concerning behaviors or symptoms that they might notice in the infant or child. The parent and/or caregiver can then discuss the questions that they and the other family members have with the child’s doctor who can then get the diagnosis process started.

That may start by having the parent and/or caregiver fill out a more thorough and comprehensive medical history form. From that, the doctor can refer the family to receive a medical assessment, as well as a mental health and developmental medical evaluation.

The earlier that a diagnosis can be received, the sooner that resources and support can be available for the child.

Final thoughts

Overall, children with down syndrome can also be diagnosed with autism spectrum disorder. They are typically diagnosed at a higher rate.

With that said, the sooner that parents and/or caregivers talk to the child’s doctor about any questions or concerns they have about their child’s behavior, actions, and/or behaviors, the better it can be for the child.

A great benefit for the child and their parent when receiving information about both autism and down syndrome would include, but not be limited to what services and support are available for their child.


Centers for Disease Control and Prevention. (2022). Facts About Down Syndrome. https://www.cdc.gov/ncbddd/birthdefects/downsyndrome.html

Patel, L., Spinazzi, N., Velasco, A., & Wodecki, D. (2023). Autism Spectrum Disorder in Down Syndrome: Experiences from Caregivers.

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