Genetics play a bigger role than environmental causes for autism
July 22nd, 2014
01:23 PM ET

Genetics play a bigger role than environmental causes for autism

Genetics plays more of a role in the development of autism than environmental causes, according to new research published Sunday in Nature Genetics.

The study found that 52% of autism risk comes from common genes, while only 2.6% are attributed to spontaneous mutations caused by, among other things, environmental factors.

“These genetic variations are common enough that most people are likely to have some,” said Joseph Buxbaum, a researcher at the Mount Sinai School of Medicine and one of the lead authors on the study. “Each one has a tiny effect on autism risk, and many hundreds or thousands together make a significant risk.”

Using Sweden’s health registry, the researchers compared 3,000 people with autism to 3,000 people without autism to determine the degrees that common and rare genes, as well as spontaneous mutations, contribute to autism risk. The study authors also compared the study’s results with a parallel study of 1.6 million Swedish families that identified specific genetic risk factors.

Buxbaum says the presence of these common genes can only determine the risk of autism, not whether or not the condition will develop. And even though spontaneous mutations only account for a small percentage of autism risk, their effect is significant.

“[Individuals] might have all the common variants there as part of their background risk, but it took this initial hit to push them over the edge,” Buxbaum said.

Chris Gunter, an autism researcher at the Marcus Autism Center and professor at the Emory University School of Medicine, says the findings of this study are similar to those reported in other studies.

“There is no one gene for autism,” Gunter said. “Instead there are many different genetic variations which each contribute a little bit to the risk of developing the group of symptoms we diagnose as autism.”

She added that we still don’t know exactly how much these different factors contribute to the development of autism.

Once scientists accumulate more data on the autism population, Buxbaum says this new research could help develop a “risk score” - such as the one that exists for heart attacks - that would help patients determine the likelihood of family members developing autism.

“The autism field has changed dramatically,” Buxbaum said. “We now have immense power to find both common and rare and spontaneous mutations in autism. That’s really the exciting part.”

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Filed under: Autism • Living Well

soundoff (28 Responses)
  1. A

    Somebody tell Jenny McCarthy that she's WRONG.

    July 22, 2014 at 14:14 | Report abuse | Reply
    • Sharon

      That's just what I was thinking!

      July 22, 2014 at 14:51 | Report abuse |
    • alain couvier

      The researchers found 41% of ASD in a Swedish population – could not be explained directly by genetics. What is not stated and which is self evident from a medical point of view that 'common genes' are each and everyone of them influenced in some way by environment.

      The general public need to understand that it is not a Gene v Environment but a complex series of interactions that can begin in utero and continue through a person's life span.

      For instance just recently researchers from the University of California added to the solid base of evidence that pollution interacts with genes in utero to raise autism risk significantly.

      That's just one of the 'environmental ' factors that are currently well evidenced and part of further investigation. Others include bacteria, viruses such influenza , measles and rubella , pesticides , toxins and heavy metals ... plus a plethora of evidence from the prenatal environment.

      Adding to this is the relationships of other diseases and disorders found in Autism , most notably the relationships of seizures , epilepsy . allergies , autoimmune diseases and gastrointestinal diseases such as Inflammatory Bowel Disease.

      Understanding the simple but complex relationships between genes and environment will see us progressively work towards new and exciting treatment regimes some as simple as prebiotics successfully shown in animal models to essentially 'cure' ... and that's more than exciting because that may mean future generations will be able to be free from depression , anxiety , bipolar , schizophrenia ...

      July 25, 2014 at 23:06 | Report abuse |
  2. Sullivan (Matt Carey)

    Thanks for this good summary.

    I think most of us still think of "single gene" genetics. It's interesting to see how genetics understanding has chanced in the past decade.

    July 22, 2014 at 17:00 | Report abuse | Reply
  3. Michael Fischer

    Great article. Thanks for sharing! http://www.voice4autism.org

    July 23, 2014 at 10:51 | Report abuse | Reply
  4. cali girl

    Where are all the anti vaccinate loons today? Autism is cause by vaccinations, autism is cause by vaccinations! The sky is falling, the sky is falling.
    Hope this lays to rest this whole stupid lie to rest.

    July 23, 2014 at 13:45 | Report abuse | Reply
    • SS

      How very proper of you to believe what you are told. Unfortunately much of what we are told is NOT true. Specifically about vaccines and more specifically the MMR vaccine. This recent news backs up what many mothers and fathers have reported about the day their baby or toddler changed – losing previous speech, motor and social skills as well as physical health. Recently the name of a CDC whistle blower was made public. He is a PhD and along with other PhDs colluded to withhold the information that their study of the MMR vaccine showed that it caused a large (320%) increase in autism in the black male child recipients. It is stated separately that blacks reacted at twice the rate of others so we can guess that other races are affected at about a 160% increase in autism. This cover up occurred 13 years ago. Since that time one of the other PhDs involved with the study actually sat before a congressional hearing and lied about the evidence. The whistle blower feels guilty, but that is much less important at this point in time than getting the information out. He knows his professional career is over, at the very least. He just wants to get this information out. We need this information in order to stop the damage. He is threatening a very profitable business line. His information tells us that we cannot trust the CDC and the individuals who purport to work to keep us safe. See what Jon Rappoport has to say. This whistle blower's reputation is at risk, his life is at risk. That is how it works when one threatens big business and big bureaucracies. He was escorted off the campus of the CDC 2 days ago. So we know that they now know who he is. It is important that we get this information and in order to do that William Thompson's name needs to be known, and he needs to be kept safe. There is a video available: http://vimeo.com/user5503203/review/103711143/91f7d3d4d8

      August 24, 2014 at 00:14 | Report abuse |
  5. cali girl

    Where are all the anti vaccinate loons today? Autism is cause by vaccinations, autism is cause by vaccinations! The sky is falling, the sky is falling.
    Hope this lays to rest this whole stupid lie..

    July 23, 2014 at 13:46 | Report abuse | Reply
  6. Something's missing...

    So 52% is caused by genetics and 2.6% by spontaneous mutations caused by environmental factors. Ok, so what about the other 46%?....not saying it's vaccines, that's been disproven, but that definitely leaves a lot of room for environmental factors to have a big role in the condition.

    July 23, 2014 at 22:29 | Report abuse | Reply
    • gladr

      The 52% is due to "common" genes....there are also rare ones that have not been accounted for in this article....just mentioned briefly.

      July 23, 2014 at 22:33 | Report abuse |
    • bepatienz

      There is a difference between "environmental factors" and "results not yet explained by genetics." This problem is often termed "missing heritability" in discussions of polygenic traits like autism or human adult stature.

      July 24, 2014 at 01:28 | Report abuse |
    • Lucy

      The study found that 52% of autism risk comes from common genes, while only 2.6% are attributed to spontaneous mutations caused by, among other things, environmental factors.
      – Environmental factors can still play a huge role among those 52% of autism risk. The key word is risk ...Among those 52% with the genes some may develop the disease...so outside factors can trigger this propensity for Autism. I do not believe this study really tell us anything more re: Autism and environment.
      Like you stated also what about the other 48%. They definitely need a more refine study. I believe environment and nutrition play a huge factor!

      July 24, 2014 at 22:44 | Report abuse |
    • alain couvier


      Well said. It isn't a black and white issue – clearly environment interacts with genes and it's not just the mother and father. The environment of prior generations can have a clear effect on genes and is a cause for great concern.

      Washington State University professor had this to say only yesterday

      ""What your great-grandmother was exposed to during pregnancy, like the pesticide methoxychlor, may promote a dramatic increase in your susceptibility to develop disease, and you will pass this on to your grandchildren in the absence of any continued exposures," says author Michael Skinner."

      * Pesticides have been linked to a significant rise in ASD risk, as has heavy metals and other pollutants.

      July 25, 2014 at 23:15 | Report abuse |
    • SS

      See the above note. It has not been dis-proven. Continuously stating the same misinformation over and over and using the tired but effective method of ridicule is the usual technique used to convince readers of a desired opinion. When actual results are hidden and scientists themselves lie, we must be more diligent and look for causes and factors that match up with the observed results. So, put the vaccine link back on the table and start to deal with it.
      I am very hopeful that those who have taken the view point that vaccines do not cause autism, because they have been misled, are able to review the information and then aim their dismay in the right direction – at the scientists who lied and the agency and pharmaceutical companies that looked after their own interests above that of the children they purported to serve.

      August 24, 2014 at 00:24 | Report abuse |
  7. mccabe1blog

    Excellent report – one of the best on genetics and risk I have ever read. Only one other observation – autism is a label for a wide contiuum of disablity – where as a heart attack is a much more distinct and less variable event. The utility of a risk score for autism would be rather different unless it was able to predict the location on the continuum not merely being somewhere on the continuum. That said – a truly excellent report. Congratulations.

    July 24, 2014 at 15:55 | Report abuse | Reply
    • alain couvier

      There is some solid evidence beginning to emerge for biological as well as genetic markers of ASD risk. These surround immune function such as C-reactive protein – an established inflammatory biomarker and urinary p-cresol ( the largest and most widespread source of this compound is represented by some gut bacteria).

      For instance c-reactive protein has been associated with a significant elevated risk for ASD and Schizophrenia focusing on infections and other insults during pregnancy.

      July 25, 2014 at 23:26 | Report abuse |
  8. EV Treatment Now

    It is likely that the pregnant mothers of these unborn children had an Enterovirus (EV) infection while they were pregnant that created a mutation in the baby's genes. If you ask a mother of an Autisitc child if they were sick while pregnant you would be clamoring for EV Treatment Now to prevent these lifelong illnesses.

    July 24, 2014 at 18:43 | Report abuse | Reply
  9. thinkthinkthink

    So, since these are common genes, pretty much anyone who chooses to have a baby can get a child with autism. Why didn't we have this much occurrence before if these genes are common? And, PLEASE stop referencing the "village idiot" scenario from colonial times. No one KNOWS they were autistic. It's an impossible to prove HYPOTHESIS. This isn't like they are saying people with blonde hair and blue eyes are more likely to have autistic children, though given that their study group was in Sweden, maybe it is. They are saying "common genes". I still think this is a pathetic effort for how long this has been around. Two weeks ago they said it was pesticide exposure. Two weeks before that it was taking high level of folic acid before getting pregnant and during pregnancy. They have changed their minds so many times about what increases the risk that it's hard to even take them seriously, anymore. "The autism field has changed dramatically"? I don't think so. They still don't have a clue what to do about it.

    July 24, 2014 at 23:54 | Report abuse | Reply
    • giulio

      simply the true! unfortunately autism and its ethiology remains still unclear...genetics cannot explain all, we can exclude vaccinations but around 50% of autism are totally unknown!

      October 22, 2014 at 12:58 | Report abuse |
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    July 27, 2014 at 23:16 | Report abuse | Reply
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    July 29, 2014 at 12:42 | Report abuse | Reply
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    August 3, 2014 at 13:37 | Report abuse | Reply
  13. GKB

    Having read this it gives one cause to ponder on the probability of the following scenario :
    Let's say a couple adopts a new born baby and within the first 18 months everything seems just perfect, but as the months roll on the parents begin to notice the child isn't as "bright", nor as interactive as their neighbor's baby...the question is twofold – Is this due to the baby's environment or simply due to a gene already in his genetic make up or dare i say perhaps both ?

    September 19, 2014 at 05:32 | Report abuse | Reply
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  15. lola fallacy

    i guess if it goes untreated cells can morph into the wrong version of the good cell. reason why it prevalent or visual and presented in poorer families. from a former biology student, completed genetics.

    October 12, 2014 at 12:54 | Report abuse | Reply
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    Using Sweden’s health registry, the researchers compared 3,000 people with autism to 3,000 people without autism to determine the degrees that common and rare genes, as well as spontaneous mutations, contribute to autism risk. The study authors also compared the study’s results with a parallel study of 1.6 million Swedish families that identified specific genetic risk factors.

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