Subscribe to the BioNews newsletter for free

Advanced Search

Search for

Like the Progress Educational Trust on Facebook



Combined genetic tests could aid autism diagnosis

07 September 2015

By Dr Ashley Cartwright

Appeared in BioNews 818

Scientists have found that two genetic analysis techniques can increase the number of causative mutations found in children with autism spectrum disorder (ASD).

The study, published in JAMA, also indicated that selecting children for genetic testing on the basis of clinical examination could help identify those who will benefit most from it.

Dr Stephen Scherer, from the Hospital for Sick Children in Toronto, Canada, and his team studied the DNA of 258 children with ASD using chromosomal microarray chip analysis (CMA), which looks for duplicated or missing segments of chromosomes.

Using this method, they found that 24 (9.3 percent) of children had a genetic mutation that could contribute towards the features of ASD.

The team also analysed the DNA of 95 randomly selected children and their parents for additional whole-exome sequencing (WES) analysis – a more extensive test that can detect single nucleotide mutations, which identified eight children (8.3 percent) as having a clinically relevant genetic mutation.

For those children where both the CMA and WES analysis had been used, the percentage of diagnoses improved to 15.8.

In addition to these genetic tests, each child also underwent a detailed physical evaluation and were categorised according to clinical morphology.

The researchers found that children with more physical anomalies (such as unusual measurements of the face, hands and feet or structural brain abnormalities) were more likely to receive a genetic diagnosis than those with fewer anomalies.

Using the combined CMA and WES testing, 36.7 percent of those with complex autism (defined as 6 or more physical anomalies) were diagnosed compared with just 6.3 percent of those with essential autism (three or fewer anomalies).

The findings from this study suggest that the rate of genetic diagnoses of ASD could be significantly improved if both CMA and WES were used as first-line genetic testing. However, Dr Scherer et al note that 'the use of WES is still largely within the research domain'.

'Our data suggest that medical evaluation of ASD children may help identify populations more likely to achieve a molecular diagnosis with genetic testing,' they add.

The authors conclude that that it is important for multiple genetic testing methods to be used in combination with detailed clinical histories and physical examinations to improve diagnosis.

Writing in an accompanying editorial, Dr Judith Miles from the University of Missouri in Columbia, agreed: 'It is incontrovertible that precise diagnoses pave the way to better medical care, improved surveillance, better functional outcomes and informed genetic counselling.'

She added that, in cases where genetic testing is harder to come by, such as for insurance or geographical reasons, clinical examination could help select a subset of children who have the highest chance of receiving a genetic diagnosis.

'It seems possible that it will not be too long before [there is a] recommendation to include whole-exome DNA sequencing as a first-tier ASD test, if not for all ASD diagnoses, certainly for children with physical dysmorphology,' Dr Miles concludes.


13 March 2017 - by Jenny Sharpe 
A study that sequenced the whole genomes of over 5000 people has discovered 18 genes associated with autism spectrum disorder (ASD)...
06 March 2017 - by Jamie Rickman 
Researchers have discovered that genetic variants associated with Autism Spectrum Disorder (ASD) also correlate with higher intelligence...
07 November 2016 - by Helen Robertson 
Children with autism spectrum disorder have twice as many harmful mutations in their mitochondrial DNA as their siblings, a study has found...
31 May 2016 - by Rhys Baker 
Genetic testing can improve the treatment of developmental delay in children when it's caused by an underlying metabolic disorder...
01 February 2016 - by Dr Julia Hill 
A Chinese laboratory has created genetically modified monkeys that show symptoms of autism...

10 August 2015 - by Antony Blackburn-Starza 
Researchers in the United States have demonstrated how a gene mutation can contribute to a particular form of autism...
20 July 2015 - by Ayala Ochert 
Scientists have grown miniature brains out of stem cells from people with autism, and have found that they over-produce one type of neuron...
16 March 2015 - by Sophie McLachlan 
Genes associated with autism have been linked to slightly higher cognitive ability when present in the DNA of non-autistic people...
09 March 2015 - by Sophie McLachlan 
A UK twin study estimates that between 56 and 95 percent of autism spectrum disorder cases are attributable to genetics...
03 November 2014 - by Siobhan Chan 
Scientists have linked 107 genes to autism, and 22 of these genes have a significant impact on the likelihood of developing the disorder, two studies published in Nature have shown...

Be the first to have your say.

You need to or  to add comments.

By posting a comment you agree to abide by the BioNews terms and conditions

- click here to enquire about using this story.

Published by the Progress Educational Trust


Public Conference
8 December 2017

Speakers include

Professor Azim Surani

Professor Magdalena Zernicka-Goetz

Professor Robin Lovell-Badge

Sally Cheshire

Professor Guido Pennings

Katherine Littler

Professor Allan Pacey

Dr Sue Avery

Professor Richard Anderson

Dr Elizabeth Garner

Dr Andy Greenfield

Dr Anna Smajdor

Dr Henry Malter

Vivienne Parry

Dr Helen O'Neill

Dr César Palacios-González

Philippa Taylor

Fiona Fox

Sarah Norcross

Sandy Starr


Good Fundraising Code

Become a Friend of PET HERE and give the Progress Educational Trust a regular donation