Home > Science > Autism in the Family – More Common Than We Thought

Autism in the Family – More Common Than We Thought

This is a guest blog post from Autism Speaks Science Board member John Elder Robison, author of Look Me in the Eye: My Life with Asperger’s and Be Different: Adventures of a Free-Range Aspergian.

This morning I read a striking a new study which addressed the question of autism in siblings – how common is it?  The findings will be of vital interest to many; most especially young families with an autistic infant.
Earlier studies and “conventional wisdom” suggested the incidence of autism in siblings was in the 3-10% range.  This new study shows those numbers to be very far from the mark.
Scientists in this new study found autism in 19 percent of the younger siblings.  High as that seems the incidence is even higher in families with two or more autistic kids.  In that case, a new sibling’s chances of being autistic rose to more than 32 percent.
Being a boy makes a difference too.  “Only” 9% of girl siblings were autistic, as compared to 26% of boys.  I found this difference quite interesting because I often wonder if autism is under-diagnosed in females.  In this study, all the kids were screened with the gold-standard ADOS or ADIR tests prior to age three.  So even with top-notch screening, we still have more autistic boys.
Those are some strikingly high percentages.  As high as they are, and knowing autism is a spectrum condition, I have to wonder how many non-diagnosed siblings will eventually turn out to have less severe but still noticeable “differences.”
There were a few more points I found interesting.  First of all, the IQ of the child did not predict anything.  Neither did severity of autism, as defined by the ADOS diagnostic scales.  So your odds of having a second autistic kid are higher, but those odds and knowledge of the first kid don’t combine to give any insight into how a second kid might end up.
The conclusion is inescapable:  autism does run in families.  According to these findings, the more autistic kids you have, the more you are likely to keep having.
We talk about autism having both genetic and environmental components.  This study, with 664 infants distributed all over the country, shows a very powerful genetic component.  That certainly does not diminish the role of environment, but it’s sobering.
I predict the results of this study will have a profound impact on family planning, because it casts parents’ chances of having a second or third child with autism in a strikingly different light that any previous study.
We already know (from other studies) that many parents stop having children when their first child receives an ASD diagnosis.  This new finding may significantly reinforce that tendency.
Read the study yourself at this link.
The study involved 664 infants from 12 U.S. and Canadian sites, evaluated as early as 6 months of age and followed until age 36 months.  Kids with previously identified autism-related genetic factors such as Fragile X were excluded from the study group.
“It’s important to recognize that these are estimates that are averaged across all of the families. So, for some families, the risk will be greater than 18.7 percent, and for other families it would be less than 18.7 percent,” said Sally Ozonoff, Ph.D., professor of psychiatry and behavioral sciences at the MIND Institute and the study’s lead author. “At the present time, unfortunately, we do not know how to estimate an individual family’s actual risk.”
This study was based on data from the Autism Speaks High Risk Baby Siblings Research Consortium (BSRC) and led by investigators from the UC Davis MIND Institute.
Your correspondent (John Elder Robison) is a member of the Science Board of Autism Speaks, one of the organizations who funded the work.
  1. August 16, 2011 at 3:14 pm

    Unfortunately this study appears to totally ignore the primary risk factor for autism among siblings which is diet. If the second child eats a diet quite similar to the older sibling diagnosed with autism, then my research suggest more than a 90% chance the second child will be diagnosed with autism! My research has shown that if the child is fed a diet that is nutritionally adequate and includes the foods that contain cholesterol and their abundance of other critical nutrients, then the risk of that sibling having autism is less than 2%.

    • Kim
      August 17, 2011 at 9:27 am

      “Dr”. Rongey, please do not post garbage like this here. Parents are desperate and you are a vulture.

    • mike b
      August 17, 2011 at 9:36 am

      This comment makes little sense.

    • Teena Slater
      August 17, 2011 at 9:38 am

      Autism has nothing to do with diet they are just wired differently, yes certain foods can send any kid on a tangent but it doesn’t change the way these kids think and react to the constant frustration they face every day because they see the world differently, I totally agree with the findings as i have an aspergers child he has two siblings that do not but has a first cousin that does and his father and uncle and auntie have. Putting diet as the primary risk factor is totally untrue.

      • Jan
        August 18, 2011 at 7:25 am

        I have heard the term “wired differently” so many times but without a clear explanation of what wire is different (or up to a 100 wires). There is no scientific proof that “wired differently” even exists. To me it is a sad euphemism for “children with unexplained pain”…What do you think?

    • Karengf
      August 17, 2011 at 1:15 pm

      Please do not post information that lessens the complex neurological nature of children with autism. I cannot possibly see how you can look at your research as cause effect when the literature shows that it runs in families throughout several generations where diets are not duplicated. PLEASE parents new to the AS diagnosis, talk to your developmental pediatrician before accepting Dr, Rongey as valid.

    • Ray
      August 18, 2011 at 10:34 am

      What the hell Dr rongey,your name should be spelled wrongey because you are so so wrong. I can’t believe you would post something so wrong and stupid.To write something like that is wrong and you have to know its wrong tells me that your either guessing or are a child trying to upset people.in my family I have a nephew who has autism and my brother and sister in law have 8 kids who all have the same diet and are all brought up the same,and are all treated the same and all loved the same.Boy you really don’t know what your talking about.

      • August 18, 2011 at 2:23 pm

        I would hope there are those who can show me where my data is wrong. My conclusions are based upon material facts that can readily be confirmed by anyone who cares to do so. Again, I do not blame parents or consider anyone stupid though many have been misinformed for many years as to what constitutes a healthy diet. I have simply compared the composition of the brain and the composition of many foods to see if the recommended healthy diets are healthy. What I found was that virtually all respondents to my survey reported avoiding the foods that contain cholesterol. These foods according to the USDA contain more brain nutrients than fruits, vegetables, grains, and the other foods that are claimed to be healthy. When those in my study fed the cholesterol containing foods they reported the symptoms disappearing within one to four weeks or they were drastically reduced.

        My research has shown those with autism to be nutritionally lacking and others have reported the same thing. To avoid autism in younger siblings I am recommending that a diet absent those deficiencies will protect subsequent siblings from having autism. I have not proven prevention but some parents have reported healing. I simply pointed out in my first comment that to have included diet as a factor would have changed their findings.

        I sincerely believe if the known nutritional deficiencies are prevented in the child’s diet, the symptoms of autism will be prevented.

    • Melissa Jacobs
      August 19, 2011 at 6:00 pm

      We spent many pointless months forcing our child to eat a Gluten and Cassein free diet. All this did was cause him to lose weight and look frail. You have no idea what you are talking about Dr.Rongey.

      • August 19, 2011 at 9:04 pm

        Perhaps I can add some clarification on my comments.

        What I am reporting is that the healthy brain contains 3% cholesterol, 3.5-4% saturated fats, 3.5-4% monounsaturated fat, about 0.5% choline and without these nutrients being supplied in the child’s diet, there will be deficiencies and resulting symptoms of those deficiencies—Autism or other neurological disorders. This data is primarily from the USDA Nutrient Database which I have confirmed to be quite accurate over the last fifty years.
        Unfortunately, the GF/CF diet includes very little if any of these critical nutrients and could not be expected to meed the needs of the brain. The GF/CF diet has been used primarily to help with digestive problems not those of the brain function.

    • Kris G.
      August 19, 2011 at 9:17 pm

      Shame on you….stop promoting yourself…..I have twin boys..one with Autism the other without. Your posts here are arrogant and you’re trying to sell a snake oil philosphy. I’m not buying it…cause it smells rancid.

    • J.H
      August 19, 2011 at 10:46 pm

      Unfortunately this study appears to totally ignore the primary risk factor for autism among siblings which is diet. If the second child eats a diet quite similar to the older sibling diagnosed with autism, then my research suggest more than a 90% chance the second child will be diagnosed with autism! My research has shown that if the child is fed a diet that is nutritionally adequate and includes the foods that contain cholesterol and their abundance of other critical nutrients, then the risk of that sibling having autism is less than 2%
      Excuse me??

      In general, the study would have shown an extremely high Autism rate for second born children IF the FIRST born(older) sibling had Autism. Why ? Because the probability(with the exception of some unusual circumstance )THAT siblings in the same household share a similar diet is very high. In other words, this study would have shown a high concordance rate between FIRST born and SECOND born siblings diagnosed with Autism. What they would NOT have been able to ascertain is the cause of this high rate.

      Nothing like a Happy Meal to bring those rates down to 2%………..

    • Prafulla
      August 26, 2011 at 3:43 am

      That means if a child is autistic, it is better to shift him/her sibling to a totally different environment or still better give them to other parents until they are say 10 yrs old.

    • AL
      August 31, 2011 at 7:16 am

      This “diet” comment is absolute garbage. Autism is in the genes and NOT the diet! Beware of ridiculous posts like this.

  2. Cynthia
    August 17, 2011 at 9:25 am

    I have a 9 year old daughter who was diagnosed with Autism 4 years ago. She is the younger of 2 children. My son is very advanced and has been taking Advanced intelligence & Gifted classes for 4 years. 2 totally different ends of the spectrum.

  3. Allison
    August 17, 2011 at 9:26 am

    Harold…Are you suggesting that a child may not be born with autism but rather develop it as a result of diet?

    • August 17, 2011 at 2:33 pm

      My research has confirmed that the practice of starting solid foods at three to four months of age was very good advice. Breast milk is nutritionally more like the chemical composition of the brain than other milk substitutes . Even so, there are some nutrients that should be added at that age. Dr. Spock recommended one to two egg yolks at that age. This was good advice and we did not experience much autism at that time. A comparison of the composition of the brain and the foods clearly shows what is lacking. Interestingly when these nutrients have been added to the diet the symptoms in many cases disappear. This has been confirmed in my studies but also in France and the US in studies with mice.
      I believe most children are not born with autism but that it is a gradual depletion of nutrients that leads to development of the symptoms and if severe enough it can lead to regression.
      I do not deny that genetic changes have been identified but my position is that those changes are the result of nutritional deficiencies and are not likely to be causal for autism.

  4. Cynthia
    August 17, 2011 at 9:29 am

    Dr. Harold Rongey, What causes the second child to have autism if they have a similar diet as the older child? My children always ate the same things because we had meals at the same time. How was I to know that it would cause my younger child to have autism? This need to made aware to more people and fast!

    • August 17, 2011 at 2:56 pm

      The concept is quite simple. If the diet normally eaten results in autism and the second child eats the same or similar diet that is lacking nutrients is it not more likely the second child will also experience the symptoms. I found two families, each with ten children. All of the children had autism in one family while all but two had it in the other family. What I found was that the two who did not have autism did in fact eat a different diet that I had predicted would be adequate to prevent autism. This looks like genetics in the first family but the results in the second family deny this. I do not yet understand why boys and girls respond differently but suspect that nutritional demands in boys during production of hormones may play a role.

  5. mike b
    August 17, 2011 at 9:34 am

    Gee… and here I thought the evil pharmaceutical companies and thimerosal was the culprit for autism…..

  6. Cassandra Pangle
    August 17, 2011 at 9:37 am

    So then according to your research my family falls in that 2%? I have a 7 y/o w/ AS and he was fed a diet of nutritious foods and a variety of them. Around 18 months old he decided that he didn’t want certain foods and textures, and there was nothing to do about it. I am sure that in your research you hav efound that children with an ASD are VERY strong-willed. In an attempt to make sure that my second son (now 3 y/o) had better eating habits I made all of his baby food here at home. All fresh friuts and veggies, lean meats, and a variety of colors and textures. He loved it! His favorite was sweet potatoes, blended with asparagus, and chicken breast. Fast forward to 30 months and it all begans to go down hill. He is slowly but surely eliminating on e food at a time and to try and make him eat soemthing that he has decided isn’t the right color, texture, or smell is declaring WW3. I can hold out…not let him eat anything else, but then he decides to hold out even more and will not eat ANYTHING at all…no matter how much time has went by since he last ate. So please, tell me, when my child had breast milk, followed by formula, then Vitamin D milk, a variety of fruits, veggies, whole grains, and meats, what could have possibly been done to prevent his ASD? Is your research actually suggesting that DIET is the primary factor in a second child being diagnosed with an ASD? Please elaborate or show me where more of your research can be found.

    • August 17, 2011 at 3:13 pm

      As I mentioned in my earlier comment the foods that are lacking are those that contain cholesterol as well as more of the needed brain nutrients than are present in fruits, vegetables, or cereal grains. My information is based upon the USDA Nutrient Database primarily and is supported by references in the literature for the composition of the body.

      I do not blame the parents at all for these problems but I do place the blame with those who have promoted the animal fat/cholesterol theory. The healthy brain contains more than 3% cholesterol, about 4% saturated fat, 4% monounsaturated fat and a far better balance of Omega 3 and Omega 6 than will be provided by the diets those professionals recommend. I am simply saying they can not defend their recommendations for good health when you compare the composition of the body to the foods they recommend.

      I have provided some free info on my web site at http://www.whostolemyfood.com and have recently set up a new web site at http://www.theautismwebsite.com

  7. Marty
    August 17, 2011 at 9:59 am

    My child was fed an adequate diet, and still developed Autism… Dr. Rongey, are you going to be yet another professional, like those of the 1960’s, that blames the mother for her child developing Autism? I certainly hope not, because blame is the last thing parents need to focus on. It would only be a drain on our already limited emotional resources. Look at studies of what percentage of parents of children with Autism are either on AntiDepressants, or are depressed and not medicated. Please don’t contribute to that problem with your unkind remarks.

  8. August 17, 2011 at 10:15 am

    I am not aware of any credible study that found diet to be a cause of autism in siblings as Mr. Rongey implied

    • August 17, 2011 at 5:02 pm

      I quite agree that credible studies are very hard to find. We have been spending billions of dollars on autism research over the past fifty years. Has anyone yet identified the cause?
      Dr. McCandless, M.D. identified the cause in 2002 in her book: “Children with Starving Brains” but several additional brain nutrients have been added to the list. By the way, Dr. McCandless, M.D. did not tell the reader how to eliminate starvation of the brain. I proposed a theory in 2008 with a book “Resolving the Mystery That Is ASD.” and have now finished a study of more than a thousand individuals with autism.

      The NIH has funded more than a thousand autism studies but I know of none that dealt with an adequate diet while more than half dealt with genetics. As in this study, I believe diet was not considered a factor and I believe their results would have been drastically different had they considered diet as a factor.

      When starting my recent study I challenged many organizations to conduct a comparable study to further confirm my theory of 2008. I had no takers but yet I challenge those who disagree that diet is a major factor in autism to show me where my data is in error.

  9. August 17, 2011 at 10:23 am

    As high as they are, and knowing autism is a spectrum condition, I have to wonder how many non-diagnosed siblings will eventually turn out to have less severe but still noticeable “differences.”

    This is very interesting to me. My little sister has severe autism. My older brother and I have always been a little “different,” but it was never enough to get us diagnosed with anything (except for ADD in my brother’s case). The differences that we have are not enough to put us on the spectrum, but in light of my sister’s diagnosis, it seems to me that our strange little quirks could be because we share some of her autistic genes.

    • Cynthia
      August 17, 2011 at 10:44 am

      There have been many studies that prove diet is the main cause of autism because more and more foods are being produced using hormones that harm some pregnancies. We never had any major problems with autism until about 10 years ago. People eat too much fast food and the human diet is a joke now! There is plenty of proof that is credible if you just search the net

    • Justine
      August 17, 2011 at 11:34 am

      Katie.. you are not alone. I’m the oldest of 3 and our younger brother has Autism. All 3 of us have the quirky/increased sensitivity when it comes to food. My differences along with yours aren’t enough to put me on the spectrum, but I strongly agree with the genetic component in Autism. Maybe more studies need to be done on older siblings where the youngest one has the diagnosis and the others don’t.

  10. teresa
    August 17, 2011 at 12:20 pm

    This makes no sense to me at all i have a set of twins a boy and girl they share eachothers food and just my son is on the spectrum… go back and do more research … i have 4 kids that all eat the same things and only one has it .

  11. August 17, 2011 at 2:23 pm

    I have a question, I have 4 children my youngest (17 years old) has autism, my second child (now 24 years old) has struggled his whole life because of severe dyslexia. Because dyslexia is on the spectrum does that prove the heredity link?

  12. August 17, 2011 at 9:43 pm

    I’m wondering if the child’s placement in the family has any effect on the severity of autism? Example: My first child is my severest; second not as severe; third even less; fourth not on the spectrum.

  13. Noreen
    August 18, 2011 at 9:31 am

    I find THIS study interesting. I also would like to see a study of the PARENTS because after checking out the books in the Library, my husband found he was very HF Autism (barely detectable). Many Males have a hard time looking at someone in the eye (Male dominance thing?) but this is one BIG indicator. If you are not looking though, you miss so MANY social things so you must be Trained to LOOK and I wonder about good eye training instruments. As far as siblings, I did NOTICE and CALLED in a REACTION to a VACCINE and I truly believe that I made a MISTAKE listening to my DOCTOR about getting a FLU shot (the baby reacted to his FLU shot). THEY HAVEN”T done studies/long term and our BABIES are their GUINNEA PIGS. These kids have ALLERGIC REACTIONS and therefore become HIGHLY ALLERGIC to things. Even my husband was Allergic to MANY, MANY things so INFLAMMATION is the main thing and it is EXASTERBATED by the SHOTS! Amen – I spoke My piece and when it effects the BRAIN it is called vaccine caused Encephylitis. THEY will find that Allergies tend to be the SAME in Sibling make ups and they are CAUSING this in small babies that can’t talk and tell us and they are UPPING the numbers in the name of HEALTH! : ( God bring the truth to light and let the DOERS in High places DO SOMETHING! We have been Misled Long Enough and Enough BABIES have suffered! They didn’t even want to ADMIT the numbers are UP – PLEASE!!! DO Something!

  14. Noreen
    August 18, 2011 at 9:35 am

    Diet does infact reduce INFLAMMATION by the way! and also Yeast but “INJECTING” 36 doses of WHAT? is SOOOO wrong! More infant mortality and more asthma and inflammation and of course, more Autism! Protect your little one like those in nature and don’t say YES 36 times! Don’t LET things happen to your baby that you’ll later regret. SPEAK UP those of you that know the truth and Don’t let the Records BE SEALED!

  15. Noreen
    August 18, 2011 at 9:37 am

    By the way, they can BLAME the moms all they want but ALL the Majority of Autistic individuals I KNOW … are MALE, so I guess they would! haha They don’t BLAME them for the healthy children now, do they ; )

  16. chelly Sellinger
    August 19, 2011 at 2:29 am

    Noreen, My son is 14 and has Aspergers. When he got the flu shot last year he soon developed a tick sound and it lasted for about 2 months. He has never had this before and I believe it was a direct result from something in the flu shot.

  17. August 19, 2011 at 12:12 pm

    hello les solicito si es posible que toda la informacion pueda ser enviada por ustedes en ESPAÑOL AGRADECIDA DE ANTEMANO QUEDA DE USTEDES, ATENTAMENTE

  18. Robin
    August 19, 2011 at 10:22 pm

    I have three daughters 13, 11, and 8. The 13 year old isn’t on the spectrum, but the younger two are. My middle daughter is considered severe to profound and the younger moderate to severe. I am certain there is a genetic link that makes siblings a higher risk for ASD, but my question is more how come my oldest doesn’t exhibit any ASD traits, while her sisters do?

  19. Barbara B Cooper
    August 19, 2011 at 10:49 pm

    My grandson has gluten free, casien free organic diet & was pretty severe at age 2. After therapy & the diet & supplements, he is 7 yrs old, gifted & outgoing. He’s very social & talkative. His diet has been relaxed a little, but he’ll need to stay on it. You CAN do it – it’s a matter of just developing a routine. Now the little brother – less severe, but still on the spectrum & silent – is getting his therapy too – the diet was started a yr ago when he stopped babbling. He’s already starting to say a few things. Dr Jerry is the bomb!! (He wrote that book with Jenny McCarthy & we got him before he was famous)

  20. Lindsey
    August 22, 2011 at 2:40 pm

    Please don’t buy Dr. Rongey’s “Snake oil.” For any interested parents wanting to learn more about the results of reliable and valid studies involving children with Autism, please visit the National Standards website. The National standards project reviewed hundreds, if not thousands, of studies to determine effective treatments(an treatments that had no effect)for children with Autism.

  21. August 22, 2011 at 5:33 pm

    I would appreciate it if you could clarify for others what you have that can refute the data upon which my research is based. I am happy to provide the proof for any of my comments to any who would contest them with facts, rather than allegations of “Snake Oil”!. Mine are taken from the USDA Nutrient Database SR 23 and the USDA report on Choline all of which are freely available online. I do have responses from over a thousand that have confirmed my theory of 2008 that malnutrition is the main problem. Others have confirmed that simply feeding two to three regular large eggs or egg yolks every day or foods that contain equivalent nutrients brought dramatic improvements for their children including some non-verbal children. My objective with my comments is to help parents understand the basic cause for most autism disorders. My major objective from my research is to extinguish this epidemic foremost and then help those with the symptoms. This is entirely possible with adequate nutrition but people must know what is required by the body to prevent the deficiencies. I look forward to your evidence of snake oil.

  22. August 26, 2011 at 3:05 pm

    It appears you misunderstand my point, I am simply stating that if you feed the same diet to the new child as was fed to the one that developed autism, then you have a 90% chance that the same nutritional deficiencies will result in the new child developing autism. However, if the new child has a diet that contains a diet that includes adequate cholesterol containing foods like whole milk, regular eggs or egg yolks, or meats then I found the chance of that new child developing autism to be less than 2% in spite of the older siblings problem.
    The chance that autism in the new child is due to genetics or environmental factors I found to be less than 2%.

  23. August 31, 2011 at 11:46 am

    I am sorry to burst your bubble but I can prove diet is the cause for most forms of autism. Some genes are altered in those with autism but I defy you or anyone else to demonstrate that such genetic change was not caused by nutritional deficiencies.

  24. October 9, 2011 at 10:36 pm

    Awesome write up. I cannot agree more with you.

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