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Studies on Down Syndrome & Autism Spectrum Disorder (DS-ASD): The Condition and How to Care

Updated: Mar 6

Examine the distinct difficulties and traits of people with DS-ASD, a complicated combination of Down syndrome and autism spectrum disorder. Learn about co-occurring condition diagnosis, support, and care.

Down Syndrome and Autism Spectrum Disorder, both are equal opportunity conditions, meaning that any parent, anywhere, can have a child with either condition regardless of their financial background, race, or creed.

Studies on Down Syndrome & Autism Spectrum Disorder (DS-ASD) - Image by Laksh Rampal
Studies on Down Syndrome & Autism Spectrum Disorder (DS-ASD) - Image by Laksh Rampal

Table of Contents:

When Down Syndrome and Autism combine, the comorbid disorder becomes more complex with increased challenges. Furthermore, patients with DS-ASD are a relatively understudied patient population, increasing the challenging nature of this condition.

The purpose of this article is to raise awareness among us for individuals with dual diagnosis of Down Syndrome with Autism Spectrum Disorder.

Let’s begin by briefly going over both conditions.


What is Down Syndrome (DS)?

Down Syndrome is the most prevalent neurodevelopmental disorder, with an estimated occurrence of 1 in 792 births.

A standard diagnosis of Down syndrome is the karyotypic evidence of an additional copy of chromosome 21's long arm. Moreover, DS can be identified prenatally (during pregnancy) using prenatal karyotype testing.

Studies have shown Down syndrome patients to have a certain sociability and openness. However, a pattern of unusual social behaviours combined with recognised language and cognitive deficits may resemble signs of autism spectrum disorder (ASD) in certain persons with DS.


What is Autism Spectrum Disorder (ASD)?

Autism spectrum disorder is a neurodevelopmental disorder. It is marked by repetitive behaviours, limited interests, and difficulties in social interactions. It may result in issues with language, thinking, feeling, and interpersonal relationships.

Doctors can diagnose Autism, by evaluating an individual’s behaviour and developmental history. Even while ASD behaviours can be detected in children as young as two, some autistic individuals are not diagnosed until they are much older or even adults.


Down Syndrome and Autism spectrum disorder (DS-ASD)

People with Down syndrome (DS) frequently co-occur with autism spectrum disorder (ASD). According to studies, 8–18% of people with Down syndrome may also have autism. A further 25% of individuals with Down syndrome might show signs of autism, but not to the extent or frequency necessary for a diagnosis of DS-ASD.

Research also suggests that children with Down syndrome may begin exhibiting autistic behaviours by the time they are three to four years old.

Characteristics of Down Syndrome and Autism spectrum disorder (DS-ASD)



Initial Symptoms

Stereotypic behaviours, such as hand flapping, stimming, and head pounding, perseverative behaviour, such as looking at ceiling fans or lights, and limited interests, such as playing with the same toy repeatedly, are the most frequently reported early concerns in Autism kids with Down syndrome, (Spinazzi et al, 2023)

Early on, communication difficulties, poor shared attention, and a lack of interest in social interactions are all commonly seen.

Growing up

Compared to other children with DS, Children with DA-ASD make less progress towards developmental milestones.

Caregivers reported having noticed Down syndrome autism connection such as poor eye contact, mood or behaviour disorders such as tantrums, hyperactivity, anxiety, and aberrant play patterns such as preferring to play alone, lacking in imaginative play, and inappropriate use of toys, as well as sensory sensitivity or defensiveness.

Additionally, self-harm and withdrawal are also forms of maladaptive behaviours that are linked to an increased chance of developing DS-ASD.

Dual Diagnosis

A lack of awareness and knowledge about DS-ASD is quite prevalent, leading to delays in diagnosis and therefore, therapeutic intervention. Education is, therefore, necessary, particularly for primary care providers and educators who are frequently the first to hear parental concerns.

For most people, the path to a dual diagnosis involves interacting with multiple providers, educators, and therapists before finding one who is able to recognise the signs of ASD and evaluate them.

Therapeutic Intervention

A rigorous early intervention has been demonstrated to improve developmental outcomes for people with idiopathic Autism spectrum disorder. Numerous therapy approaches, such as behavioural and communication support, are found to be useful.

Understand the dual analysis of DS-ADS - Image by Laksh Rampal
Understand the dual analysis of DS-ADS - Image by Laksh Rampal

Diagnosis of Autism Spectrum Disorder (ASD) in Down Syndrome (DS) Patients

There is a lag between the time an ASD diagnosis is made and the onset of symptoms. ASD diagnosis and identification in people with Down syndrome can be challenging for a variety of reasons.

The currently available measures are unable to accurately capture and separate social, cognitive, linguistic, and behavioural symptoms of Autism and Down syndrome similarities.

It is possible that confounding factors like degree of cognitive impairment, adaptive functioning or language skills lead to falsely increasing the rates of ASD diagnoses in people with significant intellectual disability.

The high incidence of hearing loss, hypotonia, and visual impairment in individuals with Down syndrome may also impact language and social development.

Also, DS-ASD exhibits less of the hallmark ASD symptoms than ASD alone, such as repetitive behaviours and interests and social-communicative deficits.

The presence of multiple signs and symptoms, along with a concern that a child is "different" from other children with DS, should prompt further medical disease evaluation by a specialist rather than being dismissed as attributable to DS or intellectual disability alone.


Recognize Signs of ASD in Individuals with DS

According to National Down Syndrome Society (NDSS), the presence of the following signs and symptoms help us identify Down syndrome and Autism comorbid:

< 3 years old

> 3 years old

Adult and Teens

  • Repetitive motor actions

  • Fascination with lights, ceiling fans, or fingers

  • Sporadic eye movements

  • Extreme aversion to food

  • Unusual play with toys or other objects

  • Receptive language impairment

  • Minimal or nonexistent meaningful spoken language, gestures, or signs

  • Developmental regression history

  • Hyper- or hypoactivity

  • Inattentiveness

  • Impulsivity

  • Disorganised behaviour

  • Unusual sensory reactivity

  • Unusual vocalisations

  • Exceptionally high levels of worry, dread, or agitation

  • Difficulty adjusting to regular changes or familiar surroundings

  • Sleep disturbances

  • Unruly behaviour

  • Enhanced repetitive and stereotypical motor behaviours

  • Fixation or fascination with inanimate objects

  • Incapacity or lack of interest in creative play

  • Rigid object manipulation

  • Increased sensitivity to specific sensory inputs

  • Frequent tantrums and outbursts, along with verbal or physical aggression

  • Extreme difficulty switching between tasks

  • Falling to the ground and staying still

  • An obvious lack of social connection or kinship with family or friends

  • An incapacity or reluctance to form bonds with peers

  • Fear or anxiety while with strangers

 It is important to be aware that many of these behaviours are typical for kids with Down syndrome at certain specific developmental stages.

Therefore, only an experienced clinician working with children with Down syndrome can conduct a complete evaluation of the child for autism spectrum disorder if one or two of these behaviours become excessive, predictable, or difficult to change.


What to do after you identify the first signs of DS-ASD?

A healthy life after dual diagnosis of DS-ASD - Image by Nathan Anderson
A healthy life after dual diagnosis of DS-ASD - Image by Nathan Anderson

A. Seek Professional Evaluation

The first thing to do if you think your child with Down syndrome is showing signs of autism is to have them evaluated by a professional who specialises in evaluating children with intellectual disabilities.

It is critical to rule out any underlying medical conditions that might be the source of the behaviours, for example; sinusitis, gastritis, ulcers, headaches, toothaches, and earaches.

Parents will be required to fill out a checklist to help with diagnosis in addition to the medical evaluation. The use of these checklists in conjunction with clinical observations will help diagnose autism in children. 

If your child has a dual diagnosis of both Down syndrome and autism, you will need to work in collaboration with your therapists, educational team, family, and doctor.

B. Interventions and Aid

Many individuals with dual diagnosis of Down syndrome and Autism Spectrum Disorder lead fulfilling lives. Therapies are most likely to be successful when started during the first year of recognizing the initial signs of ASD. This is because, during this period, brain plasticity is the highest.

Most caregivers indicate therapeutic services (such as speech, physical, and occupational therapy) and Applied Behavioural Analysis (ABA) therapy when asked about interventions that had been beneficial for their child. Specialised DS or autism centres are also mentioned by numerous parents (Spinazzi et al, 2023). These therapies can reduce or eliminate symptoms of autism, including delayed communication, social isolation, and the early emergence of stereotypes.


Experience of Family and Caregiver for Individuals with DS-ASD

It is significant to mention the challenges that families face during dual DS-ASD diagnosis along with managing the symptoms, and getting access to services for leisure, education, and rehabilitation.

Despite these challenges, a significant portion of parents report that having a kid with Down syndrome and Autism comorbid has made them stronger, more empathetic, and grateful.

A lot of families talk about feeling that they didn't fit in with either of the communities for people with ASD or DS.

(Spinazzi et al, 2023) Research indicates that social support plays a critical role in helping families of children with DS-ASD cope and lower their stress levels.

The necessity of linking families to both online and in-person support groups is highlighted by the fact that parents rely on forming a community with the families of other children who have dual diagnoses.

Image by RDNE Stock project
Awareness, patience and love, biggest healers of the DS-ASD community - Image by RDNE Stock project



It can be daunting to learn that your child with Down syndrome also has co-occurring Autism Spectrum Disorder. But be assured that a deeper knowledge of DS-ASD makes assistance more accessible, benefiting both kids and their families.

Even though parents of children with DS-ASD may occasionally feel alone, more and more resources are being made accessible to support and assist them. The requirements of people with DS-ASD are becoming more widely recognised, and initiatives to address those needs are being carried out all over the world.

If you find yourself on this journey, there is a kind network of professionals and families out there who genuinely realise how different the DS-ASD journey is.

Please feel free to reach out to us at Project C Foundation, where we offer support and awareness for your journey and help you connect with those who are on a similar path.

You don't have to go through this alone, we are here to help you along the way.



1)  How do I proceed if I believe a loved one suffers from DS-ASD?

The first thing you must do is go to a paediatrician or primary care physician if you suspect your loved one with Down syndrome also has autism. They can arrange for a professional evaluation. A developmental paediatrician, neurologist, psychologist, psychiatrist, or other specialist in autism examination can make a formal diagnosis of autism. 

In order to rule out medical conditions other than autism that could impair behaviour and cognition, your doctor will also prescribe some tests. Thyroid function testing and vision and hearing screenings are some of them.


2)  Which symptoms are most frequently observed in patients with co-occurring diagnoses?

Comorbid diagnoses are associated with lower IQs, fewer adaptive behaviour skills, and inferior expressive and receptive language abilities. Compared to individuals with DS alone, those with comorbid ASD have also been found to exhibit higher levels of stereotypy and disruptive behaviour.


3)  Which difficulties are most commonly mentioned by people with DS-ASD?

The most commonly mentioned difficulties in those with DS-ASD are poor social skills, cognitive rigidity, emotional and behavioural problems, and/or communication impairments.

4)  Which screener is most frequently used to assess autism spectrum disorders? Is it accurate for diagnosing DS-ASD?

Scale of Social Responsiveness (SRS) A 65-item survey called the SRS is a Parent Report Form questions parents about their child's behaviour throughout the previous six months (Channell et al, 2015). The items are grouped into five subscales based on observable features of reciprocal social behaviours:

  • Social Awareness: The capacity to recognise and interpret social cues

  • Social Cognition: The capacity to decipher social signs after being detected

  • Social Communication: The Motor Components of Mutual Social Conduct

  • Social Motivation: The drive to act in a socially and interpersonally acceptable manner

  • Autism Mannerisms: indicative actions or extremely narrow interests that are indicative of autism

A score (T) of 60–75 represents the mild to moderate symptom range. A score above 75 represents severe symptom range, and that below 60 falls within the normal range.

Furthermore, the SRS is not a very useful screener for people with ASD+DS because there is no published data on its use in people with DS, whether or not they also have a comorbid diagnosis of ASD.


5.  Which treatments were thought to be most beneficial for an ASD child?

It is crucial to treat the child with patience, understanding, compassion and kindness. The following interventions have been deemed beneficial with ASD patients (Lindgren et al, 2011):

  1. Applied Behaviour Analysis (ABA): The practice of using behavioural principles to modify particular behaviours while also assessing the intervention's efficacy is known as applied behaviour analysis, or ABA.

  2. Early Intensive Interventions: It has been demonstrated that ABA-based intensive early intervention programmes, frequently in conjunction with developmental techniques, increase behaviour, communication, and cognitive capacities.

  3. Social Skills Training: Direct social skill training interventions can be successful. Research suggests that certain social skills (such making eye contact, focusing together, saying hello, etc.) can be acquired through targeted instruction.

  4. Peer-mediated therapies have also been shown to be an effective means of fostering social skills.

  5. Cognitive-Behavioral Intervention: One of the most popular non-pharmacologic therapies for mental and emotional illnesses, particularly depression, is cognitive behavioural therapy (CBT), and its application to people with autism spectrum disorders is expanding.


Key Takeaways

  • There is more than a 10% chance that kids with Down syndrome also have an autism dual diagnosis.  

  • Individuals with Down syndrome and autism may exhibit some similar behaviours, leading to delayed diagnosis of ASD in individuals with DS.

  • Strategies and interventions that work for autistic individuals can also frequently work for those with DS-ASD.

Written by Laksh Rampal

Edited by Virginia Helzainka


Spinazzi, N.A., Velasco, A.B., Wodecki, D.J. et al. Autism Spectrum Disorder in Down Syndrome: Experiences from Caregivers. J Autism Dev Disord (2023).

Lindgren, S., Doobay, A. Evidence-Based Interventions for Autism Spectrum Disorders. Iowa Department of Human Services by the Center for Disabilities and Development of the University of Iowa Children’s Hospital (2011)

Hodges H, Fealko C, Soares N. Autism spectrum disorder: definition, epidemiology, causes, and clinical evaluation. Transl Pediatr. 2020 Feb;9 (Suppl 1): S55-S65. 

Channell, M.M., Phillips, B.A., Loveall, S.J. et al. Patterns of autism spectrum symptomatology in individuals with Down syndrome without comorbid autism spectrum disorder. J Neurodevelop Disord 7, 5 (2015).

Carter JC, Capone GT, Gray RM, Cox CS, Kaufmann WE. 2007. Autistic-spectrum disorders in Down syndrome: Further delineation and distinction from other behavioral abnormalities. Am J Med Genet Part B 144B:87–94. 



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