The genetics of autism
Nature has published a paper on the genetics of autism, which we report here. Over the coming days and weeks, we will post updates on this important story, together with links to sources of further information
• Story summary
• Email us an update on this story or other useful links
• Parents' autism questions answered
• Recent Guardian news stories related to autism
• Nature has made this paper freely available in its entirety
Thursday June 10, 1:00pm: Interesting to see how this story has been covered in different places. The Nature news blog applies its trademark clarity on who did what and what they found and contains some inteersting detail on the actual variants uncovered in the research, such as "one region of the X-chromosome, called the DDX53-PTCHD1 locus, were associated with a three-fold higher risk of autism spectrum disorder."
Mark Henderson in The Times raises the possibility of genetic tests for autism. Over at The Independent the main story by science editor Steve Connor claims that the latest Nature research is the "first significant link between autism and DNA" while health editor Jeremy Laurence argues that the "biggest puzzle about autism is the huge rise in cases, up 12-fold among children in the past 30 years, according to some estimates". Not sure about the premise of the Indy's news story, especially given that several gene variants were implicated in autism barely a year ago and the results published in Nature and the Annals of Human Genetics. See the Guardian, Times and WebMD.
At the Telegraph, Richard Alleyne blames autism on "rogue genes". The Mirror also a short report.
By the way, several commenters seem concerned at the implications of the research, asking why was it done and wondering whether it is just a way to brand autism as a disease that can and should be eliminated. For anyone thinking that, I'd suggest you read Charlotte Moore's article in the Guardian, explaining what the Nature study means to her.
Next update will include bloggers' reactions so far, so send me any links you think are worth including. So far I quite like Discover for its impressive detail.
Wednesday 8.33pm: Gina Gómez de la Cuesta, action research leader at The National Autistic Society, says: "This study furthers our understanding of genetic variation in autism, however there is a great deal more research to be done. Research into autism is constantly evolving but the exact causes are as yet still unknown. The difficulty of establishing gene involvement is compounded by the interaction of genes with the environment. Genetic testing for autism is still a long way off, given that autism is so complex. Whilst it is very important that research continues, it is also crucial that those living with the condition have access to appropriate advice and information, as the right support at the right time can make an enormous difference to people's lives."
8.29pm: Anthony Monaco, a geneticist at the University of Oxford, re-iterated Gallagher's point by saying that the genetic picture of autism was too complex to make meaningful predictions right now.
"One can only offer, when we have a lot more data, an understanding of the probability of an outcome given you've inherited a CNV. It's not like cystic fibrosis or muscular dystrophy or other single-gene disorders where one can say with a lot more certainty that if you have a mutation in that gene then a pre-natal diagnostic test can be done and you can predict with fair certainty that the foetus does or does not have the mutation and will probably get the disorder. Here we're talking about low probabilities and risks and that will be the big issue with pre-natal testing and we won't be able to think about this until we gather a lot more information. Even with all that, it may be difficult to offer the certainty a person wants from a pre-natal test."
8.24pm: What about genetic tests?
"Of course parents are going to rush out and want to get the tests done," said Louise Gallagher, clinical senior lecturer in psychiatry at Trinity College Dublin. But she warned that DNA microarrays â€" the technology needed to test for the autism gene variants â€" are not yet widely available in hospitals.
In any case, no one knows enough yet to be certain about the implications of having a certain set of genetic variations. "However, in future as we know more about the role of CNVs in contributing to autism and how they influence the progress and course of the disorder over the lifetime of the individual, the more [parents] will be able to get clinical information about their child's condition."
8.15pm: Scherer adds: "If you look at studies published to date, the most convincing finding of an aetiologic role in autism comes up with genetics. There've been estimates from numerous studies around the world from the last 20 years that 70-95% of autism has some genetic contribution ... With the rare CNVs, we can account for upwards of 10-15% of the genes involved now. There might be others that we have not yet detected. And certainly some of these genes may be influenced by environment. As far as I'm aware, through epidemiological studies, there's no [evidence of] strong influence from these other [environmental] factors yet."
8.08pm: Geri Dawson of Autism Speaks, a charity that helped to fund the research, addressed the question of environmental factors in autism. "We do believe that environmental factors play a role in autism," she said. "We don't yet understand the role of these factors so currently scientists are exploring a wide range of these factors to understand how they might interact with underlying genetic susceptibility."
For anyone worried about the effect of vaccines, she said there "really is no strong evidence that vaccines play a role in the aetiology of autism. This study really points out the strong influence of genetics. At the same time, research is continuing to explore a wide range of environmental factors that may then interact with genetic susceptibility. Currently there is no evidence that vaccines are one of those aetiological factors."
7.33pm: Stephen Scherer of the Hospital for Sick Children in Toronto, Canada, said the study starts to tie together the genes they have identified with biological pathways and networks. "They seem to be involved in how the brain functions," he said. "Knowing these autism genes are linked, we can begin to develop rationally derived therapies to target the common pathways involved for the very first time."
For example, some of the genes implicated in the latest research are known to be involved in both neural cell development and signalling pathways.
In the largest study ever to look at the genetics of autism, scientists have identified rare genetic variations that were 20% more frequent in children with autism than in children without the disorder. These so-called "copy number variations" (CNV), which can be missing chunks or extra copies of DNA in and around the genes, occur in less than one in 100 people in the general population.
In the study, scientists compared the incidence of these rare CNVs in 996 people with autism spectrum disorders and 1,287 unaffected people, all with European ancestry. The results, published today in Nature, showed that some of the CNVs were inherited while others were found in children but not in their parents.
Read the Nature research in full.
To submit suggestions for updates to this story tracker, please email guardianscience@gmail.com putting "Autism story tracker" in the subject line.
Here are some sources of further information for parents about autism on guardian.co.uk
Your autism questions answered â€" a handy resource for parents
Summary
What is it?
What are the symptoms?
How common is it?
What will happen to my child?
How do doctors diagnose it?
Questions to ask
What treatments work?
Autism spectrum disorder
Medical causes of autism
MMR vaccine and autism
Recent Guardian news stories related to autism
Andrew Wakefield struck off register by General Medical Council
Lancet retracts 'utterly false' MMR paper
Autism just as common in adults, so MMR jab is off the hook
Scientists find genetic clues to how autism can develop
Autistic traits linked to high levels of testosterone in the womb
For a complete list of Guardian articles on autism go to http://www.guardian.co.uk/lifeandstyle/autism
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