Page URL:

Twenty-five genetic variants for autism discovered

21 January 2013
Appeared in BioNews 689

Rare genetic variant may have a significant impact on a person's risk of developing autism, research suggests. In one of the largest genome-wide studies of its kind, scientists have identified 25 'high impact' genetic variants that are associated with the developmental disorder.

'Many of these gene variants may serve as valuable predictive markers', said Dr Hakon Hakonarson, director of the Centre for Applied Genomics at the Children's Hospital of Philadelphia, who led the study. 'If so, they may become part of a clinical test that will help evaluate whether a child has an autism spectrum disorder'.

Existing genetic test for autism focus on single letter changes in DNA called single nucleotide polymorphisms. The authors of the current study instead investigated the effect of copy number variants (CNVs). CNVs are deletions or duplications of large stretches of DNA, resulting in either an increase or a decrease in the number of copies of genes encoded by that DNA.

In the study published in the journal PLOS ONE, scientists first analysed the DNA from 55 families with multiple members diagnosed with autism spectrum disorders (ASDs) and identified 153 CNVs that could potentially be linked to the disorders. They then investigated the prevalence of these and other previously reported CNVs in 3,000 people with autism and 6,000 people in a control group.

Of these CNVs, 25 novel variants were found to be associated with autism, such that a person carrying the variant was suggested to be twice as likely to develop the disorder as someone who is not.

The study was performed in collaboration with the genetic diagnostics company Lineagen and the authors hope that the newly identified variants will be useful clinically.

'These high-impact variants could be most useful in advising parents who already have one child with an ASD', said Dr Hakonarson. 'If a second child has delays in reaching developmental milestones, testing for these CNVs could help predict whether that child is also likely to develop an ASD'.

Genetic tests for autism are already commercially available, although some scientists and clinicians remain sceptical of the value of this approach. Speaking to the Salt Lake Tribune, Professor Lynn Jorde, chair of the department of human genetics at the University of Utah, said that scientists have identified fewer than 20 percent of the genes linked to autism.

'Any genetic testing is only going to identify a small portion of cases', he said. 'Families should be aware that even if the child has been diagnosed as autistic, genetic testing probably won't find a cause'.

Autism And Genetics: It's Complicated
Forbes |  16 January 2013
Identification of Rare Recurrent Copy Number Variants in High-Risk Autism Families and Their Prevalence in a Large ASD Population
PLOS ONE |  14 January 2013
New Autism-Related Gene Variants Discovered
Philadelphia Business Journal (press release) |  15 January 2013
New Gene Variants Linked to Autism
Time |  15 January 2013
University of Utah scientists find 24 new genetic markers for autism
Salt Lake Tribune |  18 January 2013
15 July 2013 - by Richard Fadok 
Whole genome sequencing suggests that around half of all people with autism may be carriers of genes already associated with the condition...
29 April 2013 - by Dr Daniel Grimes 
A study on identical twins with distinct autistic traits suggests that epigenetic factors may be important in understanding how the neurological disorder develops...
22 April 2013 - by Richard Fadok 
For a self-described 'look inside your genes', this programme did what it set out to accomplish but ultimately obscured the real complexity of autism spectrum disorders...
25 March 2013 - by Matthew Thomas 
Men who father children later in life are more likely to have grandchildren with autism, according to research...
4 March 2013 - by Dr Anna Cauldwell 
Five of the most common psychiatric disorders share genetic risk factors, an international study published in the Lancet has found...
17 September 2012 - by Dr Victoria Burchell 
A genetic test capable of predicting a person's risk of Autism Spectrum Disorders (ASDs), with an accuracy greater than 70 percent, has been developed by researchers...
10 September 2012 - by Suzanne Elvidge 
A rare form of autism, caused by a mutation that alters amino acid metabolism, could potentially be treated with a nutritional supplement, according to an international team of researchers...
28 August 2012 - by Nishat Hyder 
Stem cells harvested from patients' own umbilical cord blood are to be trialled in the US as treatment for children with autism...
16 April 2012 - by James Brooks 
Genetic mutations that occur spontaneously in sperm and egg cells may increase a child's risk of autism, say scientists...
26 March 2012 - by Dr Rosie Morley 
Faulty genetic mechanisms particularly active in early life may lead to people developing autism, research suggests...
to add a Comment.

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

Syndicate this story - click here to enquire about using this story.