down syndrome and autism spectrum disorder

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6 Voice , Winter 2009. Down Syndrome Victoria Members Journal

Down syndromeand autismspectrum disorder

Research

by Dr Catherine Marraffa Deputy Director,Developmental Medicine Royal Childrens Hospital, Melbourne

The diagnosis of Down syndrome is made by the childs

appearance and confirmed when the chromosomes are

examined. Mostly this occurs in the early days or weeks

of life. Autism is a diagnosis made by detailed history and

observation of behaviours by skilled professionals usuallyworking in a team. There is no specific blood test or scan

that can make the diagnosis.

Incidence of autism

Until recently autism was considered a rare condition

(4 in 10,000 people). We now consider autism as a spectrum

disorder and that the incidence is 1 in 160 people according

to Australian figures. Other countries report 1 in 150 or

even 1 in 100 people in the general population.

Between 1979 and 2002, 36 cases of autism and Down

syndrome occurring together had been reported in the

literature. 24 were children and 12 were adults. Those who

had been tested had severe cognitive impairment. We now

believe autism can occur in about 7% (range 1%-10%) of thepopulation of people with Down syndrome, and therefore it

occurs at a much higher rate than in the general population9.

What is autism?

There are two internationally recognised systems used

to help define autism along with many other diseases and

disorders. The International Classification of Diseases10

(ICD) is used in the UK and Europe whereas the Americans

use the Diagnostic and Statistical Manual of Mental disorders

IV (DSM). These classification systems are revised regularly

as new and important information about various conditions

is learned.

Autism is a lifelong, neurodevelopmental disorder and has

three core components: communication impairments, social

impairments and limited and restricted interests. These

core components must be present before the age of three

years. Children present as two groups, those whose parentshave concerns from the very early months of life and a

second group (about 30%) whose parents report normal

development until about 18 months of age and then the

children regress and have loss of language and social skills.

Many terms are used and this can be quite confusing

for parents and professionals. Pervasive developmental

disorders is a term used in the classification systems to

include autistic disorder, atypical autism, high functioning

autism /Asperger syndrome and Pervasive Developmental

Disorder Not Otherwise Specified (PDD-NOS). The term

autism spectrum disorder was suggested in the mid 1990s

by Dr Lorna Wing and is generally preferred as it indicates

the range of presentations of autism. However the threecore components must be present to reach a diagnosis.

Many of the symptoms and behaviours overlap with other

conditions such as obsessive compulsive disorder, attention

deficit hyperactivity disorder and anxiety disorder and indeed

these conditions all overlap and are often co morbidities.

Dual diagnosis Autism and Down syndrome

what do we know?

A group of researchers at the Kennedy Krieger Institute and

the Johns Hopkins University School of Medicine, Baltimore,

Maryland has been collecting data and doing research with

children who have a dual diagnosis of autism and Down

syndrome for some years now 5,6. From the mid nineties they

For a long time, autism and Down syndrome were not thought to occur together and familieswere often told their childrens difficulties were related to the associated cognitive impairmentin Down syndrome. But a case of infantile autism was first described in the literature in achild with Down syndrome by Dr Wakabayashi in 1979 in Japan2. In the same year, Dr LornaWing and Dr Pat Howlin noted in a study of 35,000 children with a range of intellectualdisabilities in Camberwell London that some were sociable and some were not11.

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Voice , Winter 2009. Down Syndrome Victoria Members Journal 7

Research

have performed a number of tests including psychological

tests, medical evaluations, radiological examinations and

behavioural testing.

An important finding is that children with autism and Down

syndrome also tend to fall into two groups. One group has

symptoms from early infancy and toddlerhood and another

group has regression with loss of language and social skills.

However the second group regresses at a much later age

than seen in children with autism alone.

A recent small study, done in Cincinnati, compared children

with regression in autism alone to those with regression in

children with a dual diagnosis. This supported previous

reports that children with both autism and Down syndrome

had a later onset of regression at between 3-8 years of age

compared to the regression seen in children with autism

alone (18 months-2 years)8.

Symptoms and behaviours of autism in children

with Down syndrome.

Parents often notice that their child with Down syndrome

is developing differently from other children with Down

syndrome of the same developmental age. There is some

evidence that those children who have additional health

problems, such as post cardiac surgery brain injury, epilepsy

(infantile spasms) and hypothyroidism, are at greater risk

of developing autism. A family history of autism may also

increase the risk for a child who has Down syndrome.

A study from Sweden of children with Down syndrome and

autism showed considerable delay in the diagnosis of autism.

Average age of diagnosis was 14.4 years (standard deviation

7.6 years, range of 4-33 years) 7. From the work of the group

at Kennedy Krieger Institute, we know that children with

Down syndrome and autism have a lack of social interest

in peers and social withdrawal, very odd bizarre stereotypes

and anxiety. Other symptoms such as a fascination for lights

and spinning things like fans or wheels, a need for extreme

routine and repetitive behaviours such as finger twirling,

hand flapping and repetitive play are also present.

As well as these, there can be extreme sensitivity to

particular sounds, places, smells, leading to distress and

anxiety often manifest as a temper tantrum or meltdown.

Children may not respond to their name being called and

they may show little interest in playing with toys. Thoughthey may develop language, the functional use of language,

such as to greet someone or to communicate with another

in a two way conversation is limited. They may lose language

(regression) or never develop any words.

Other features which may indicate autism

for sameness and predictability.

eye poking .

lining them up in strict order.

their ears or having a tantrum when a baby cries or a

certain advertisement comes on the television) sensitivityto seams or labels on clothing, difficulty with sensory play,

such as with Playdoh, sand, paint and water.

of certain foods. Food texture, temperature and taste

may be factors.

social interest.

How to get a diagnosis

It is recognised that a multidisciplinary team approach ismost helpful when considering a diagnosis of autism in a child,

adolescent or adult. In Victoria there are autism assessment

teams in the each of the Child and Adolescent Mental Health

Services (CAMHS). Other teams providing a multidisciplinary

assessment are based in paediatric units in public hospitals

throughout the state. There is also a number of private

practitioners who work in the area of autism and they too

can offer assessment. Some of these practitioners have

expertise in making a diagnosis in adults.

A detailed medical, psychological and speech and language

assessment is needed. Even in non-verbal children, an

assessment of their communication system or style is vital

to help understand their needs. Similarly, a cognitive testingcan highlight particular learning difficulties or strengths.

Why make the dual diagnosis?

A diagnosis is important so that the appropriate educational

program and support can be offered to allow children to

achieve the best possible outcomes. Children with Down

syndrome and autism may learn differently from children

with Down syndrome alone. It is also useful for parents to

understand and manage unusual or aggressive behaviours and

learn how to prevent them. These behaviours can sometimes

be viewed as the child being naughty or attention seeking and

instead they are due to anxiety and social difficulties.

A number of cognitive, behavioural and pharmaceutical

treatments are beneficial for some of the symptoms ofautism. These can help the young person be less stressed and

anxious and more available to learn and interact with others.

How to get help with the diagnosis of autism

Autism Victoria is a useful resource to help parents with

identifying appropriate support and help for their child.

Autism Victoria

24 Drummond St,

Carlton VIC 3053

(03) 9657 1600

www.autismvictoria.org.au



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8 Voice , Winter 2009. Down Syndrome Victoria Members Journal

Research

References

1. Collins VR, Muggli EE, Riley M, Palma S, Halliday JL. (2008)Is Down

syndrome a disappearing birth defect? J Pediatr. Jan;152(1):20-4

2. Wakabayashi, S. (1979) A case of infantile autism associated with Down

syndrome Journal of Autism and Developmental Disorders, 9, 31-36.

3. Ghaziuddin, M.. Tsai, L., Ghaziuddin, N. (1992) Autism in Downs syndrome:

presentation and diagnosis. Journal of Intellectual Disability Research, 36,

449-456.

4. Matson, Johnny L., Wilkins, Jonathan and Ancona, Martin (2008) Autism

in adults with severe intellectual disability: An empirical study of symptom

presentation, Journal of Intellectual & Developmental Disability, 33:1, 36-42

5. Carter, John C. Capone, George T., Kaufmann, Walter E. (2008 Apr 16)

Neuroanatomic correlates of autism and stereotypy in children with Down

syndrome Neuroreport 16;19(6): 653-6

6. Carter John C, Capone George T., Gray Robert M. Cox Christiane S,

Kaufmann Walter E. (2006) Autistic-Spectrum Disorders in Down Syndrome:

Further Delineation and Distinction from Other Behavioral Abnormalities

Am J Med Genet Neuropsychiatr Genet Part (B)

7. Rasmussen P, Brjesson, Wentz E, Gillberg C. (2001 Nov) Autistic

disorders in Down syndrome: Background factors and clinical correlates

Dev Med Child Neurol 43 (11): 750-4

8. Howard J, Molloy C, Patterson B, Hickey F, Castillo H. (2006 Oct 13)

Age of developmental regression in children with autism with and without

Down syndrome Kentucky Junior Academy of Science Psychology

Undergraduate Research Competition.

9. Kent L, Evans J, Paul M, Sharp M. (1999 Mar) Co morbidity of autistic

spectrum disorders in children with Down syndrome Dev Med Child Neurol

41 (3): 153-8

10. Howlin P, Wing L, Gould J. (1995 May) The recognition of autism in

children with Down syndromeimplications for intervention and some

speculations about pathology Dev Med Child Neurol 37 (5): 406-414

11. Wing L, Gould J. (1979 Mar) Severe impairment of social interaction and

associated abnormalities in children; epidemiology and classification J Autism

Dev Disord 9 (1): 11-29

Dr Catherine Marraffa (MBBS FRACP FRCPCH) has worked with

children with a wide range of developmental disabilities, both

physical and intellectual, over the last 20 years. She is the Deputy

Director, Developmental Medicine at the Royal Childrens Hospital,

Parkville, and Paediatrician to the Autism Assessment Team of theIntegrated Mental Health Service. She has been in this position for

14 years. Previously, she was a Consultant Paediatrician at Central

Middlesex Hospital, London, for six years. She has co-authored

several recent papers and book chapters on children with autism

and other related topics. She is on the Board of the Olga Tennison

Autism Research Centre.

Dr Marraffa was Chair of the Royal Australasian College of

Physicians, Victorian State Committee (Paediatrics and Child

Health Division) from 2004-2008.

Down Syndrome Victoria is investigating the demand for

a peer support group for parents of a child with a dualdiagnosis. Please contact [email protected] or phone

Sue Modra on 1300 658 873 if interested.


down syndrome and autism spectrum disorder

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