Scientists Reveal New Insight Into the Genetic Causes of Autism and ADHD

Genetic Disease Research Concept

The study examines genetic variations in the genomes of 34,462 people diagnosed with autism spectrum disorder and/or ADHD, and 41,201 control subjects without these diagnoses (a so-called GWAS, genome-wide association study). For each person, 8.9 million frequently occurring genetic variants have been examined, spread across the entire genome.

Researchers have identified new gene variants that influence your risk of ADHD and autism. 

In the group of neurodevelopmental disorders, ADHD and autism have a number of things in common: They are two of the most frequent child psychiatric diagnoses; both are highly heritable; and, although the fundamental symptoms vary, autism and ADHD have a large overlap in their underlying genetic origins.

Anders Børglum

Professor Anders Børglum has headed a study that provides new insight into the biological basis for developing both autism and ADHD, or just one of the diagnoses. Credit: Lars Kruse, Aarhus University

Researchers have now discovered five gene variants that are unique to only one of the two diagnoses, as well as seven genetic variants that are shared by both ADHD and autism.

“We have succeeded in identifying both shared genetic risk variants and genetic variants that differentiate the two developmental disorders,” says Professor Anders Børglum of the Department of Biomedicine at Aarhus University and iPSYCH, Denmark’s largest research project within psychiatry, which is behind the study.

“That means that we are beginning to understand both the biological processes that are behind the development of both diagnoses, and – as something completely new – also the processes that push the developmental disorder specifically in the direction of either autism or ADHD.”

What happens in the brain?

The brain’s nerve cells, as well as how it grows and communicates, are impacted by the gene variants. The fact that some of the genetic variations identified have an effect on people’s cognitive skills in general in the population is also noteworthy.

Researchers may observe, for example, that certain genetic variants that only raise the risk of autism also boost cognitive functions in individuals, while complementary variants that only increase the risk of ADHD lower cognitive functions in individuals.

Researchers have also discovered a gene variant that increases the chance of autism while also decreasing the volume of a particular brain region in the general population, but the complementary variant raises the risk of ADHD while also increasing the volume of the same brain area.

Altered diagnostic guidelines

It may seem obvious, but the study is the first in the world to show that people with both ADHD and autism are double-burdened with a genetic risk of receiving both diagnoses, whereas people who only have one of the diagnoses for the most part only bear the genetic risk variants for this one condition.

“This means, for example, that people with both diagnoses have both an equally large load of ADHD genetic factors as people who only have ADHD, and at the same time the same large load of autism genetic factors as people who only have autism. So it makes very good biological sense that some people have both diagnoses,” says Anders Børglum.

The researchers analyze large datasets of genetic profiles in order to learn more about diseases and developmental disorders. This can make it possible to create more precise diagnoses and earlier interventions, and ensure that the individual patient receives the right treatment.

“The autism diagnosis is typically made before an ADHD diagnosis. So if, for example, the person is also hyperactive and finds it difficult to concentrate, this may well be slightly drowned out by the autism symptoms, and we may not see the ADHD challenges,” explains Anders Børglum.

“But if we have a genetic study of a person with an autism diagnosis, and we see a major genetic load of ADHD genetics, then it may be that we should monitor that person a bit more closely. In this way, we can in the future become quicker to spot the development and give the family good tools to handle this diagnosis, too. “

A few years ago – due to an official diagnosis hierarchy – it was not in principle possible to diagnose ADHD in a person who had autism, he says.

“But now we have shown that people with both diagnoses are in fact double burdened with the genetic risk of both developmental disorders. There is thus a clear biological difference between whether you have both diagnoses, or just one. The study is therefore a strong biological argument for the revised diagnostic guidelines, e.g. in the American Diagnosis and Classification system for Mental Disorders (DSM-5), where it is now possible for the same person to receive both diagnoses,” says Anders Børglum.

“This is the first step. Here and now, the study is relevant because it helps to create a better understanding of the causes of the two developmental disorders, and in the long term, this can form the basis for better diagnostics and treatment.”

Reference: “Identification of shared and differentiating genetic architecture for autism spectrum disorder, attention-deficit hyperactivity disorder and case subgroups” by Manuel Mattheisen, Jakob Grove, Thomas D. Als, Joanna Martin, Georgios Voloudakis, Sandra Meier, Ditte Demontis, Jaroslav Bendl, Raymond Walters, Caitlin E. Carey, Anders Rosengren, Nora I. Strom, Mads Engel Hauberg, Biao Zeng, Gabriel Hoffman, Wen Zhang, Jonas Bybjerg-Grauholm, Marie Bækvad-Hansen, Esben Agerbo, Bru Cormand, Merete Nordentoft, Thomas Werge, Ole Mors, David M. Hougaard, Joseph D. Buxbaum, Stephen V. Faraone, Barbara Franke, Søren Dalsgaard, Preben B. Mortensen, Elise B. Robinson, Panos Roussos, Benjamin M. Neale, Mark J. Daly and Anders D. Børglum, 26 September 2022, Nature Genetics.
DOI: 10.1038/s41588-022-01171-3

30 Comments on "Scientists Reveal New Insight Into the Genetic Causes of Autism and ADHD"

  1. What are the genetic variants?

  2. Are neanderthals or denisovans more prone to autism and ADHD?

  3. Interesting comment Craig. I’m diagnosed with both so is my husband and our children all are one or both diagnosis. I have speculated that we are simply the remnants of the ancient bloodlines that have been identified yet supposedly gone away. Such as neanderthal and denisovans. I have comically compared it to dog breeds. Dogs are all dogs yet the husky is bred for pulling, digging, colder weather. The lab is bred for protection and hunting. Both are dogs yet both carry genes that effect their outward appearance and also their basic behavior. Both can be trained in a way to elicit a certain behavioral response yet one may naturally do it over the other. To me it seems similar to the ND VS NT experience. Just my opinion tho.

  4. A very interesting study! Though my concerns with this kind of thing continue to be how these genetic studies may be used by the groups that intend to “cure” or otherwise harm autistic people. Studies like this could be very useful to autistic people in the right hands, but could also be very harmful in the wrong hands, considering the prevailing mentality of eugenics in too many places in our modern world.

  5. Craig, your question cannot be answered. There are no living Neanderthals or Denisovians to evaluate, so we cannot determine how common the conditions would be. Also, there is a lot of room for debate as to whether these labels would even make sense in the context of different species. This is why the literature refers to “mouse models of autism” and not “autistic mice”, for example.

    Sarai, the portion of human DNA inherited from these other species is very small, and is even more limited in certain geographic regions, particularly Africa. And yet peoples indigenous to Africa can be autistic or have ADHD. I find it doubtful that our cognitive differences can be attributed to Neanderthal or Denisovian genetic contributions. It’s more likely that these conditions are a side effect of active natural selection towards increased intelligence in humans. Many of the heritable genes that are associated with ASD or ADHD are also associated with increased intelligence. The picture that is emerging is that these genes contribute to intelligence but, due to their novelty in the human genome, also result in some fragility and susceptibility to certain rare genetic mutations. Evolution has not had sufficient time to generate a robust framework of protections against mutations that might interact poorly with these new genes for intelligence.

  6. What are the SNPs ? I have my 23andme raw data and knowing if they are in there would be most welcome.

  7. This is incredible but I feel like if we look too much deeper into this someone will accidentally have a eugenics moment and that’s bad for everyone, not just us Autistic people people with ADHD.

  8. I’d like the SNPs too

  9. The Vaccine crowd are still trying to say it’s not their fault.

  10. I’m in line behind Bruce.

    Please share the genetic details.

  11. This article explains my 120 IQ toe walking socially awkward adhd child. Doctors don’t believe me when I tell them she’s got to be on the Spectrum in some sort of aspy way not just adhd.

  12. Were any of the subjects in the study also diagnosed with with fragile-x syndrome?

  13. This study grabbed my eye due to the fact I have a daughter diagnosed with ADHD at 6 who is now 24 and functioning well in society on her own and a son who was early diagnosed with Autism, high functioning. There’s no history in my husband or my side but my daughter who has a different father, he was diagnosed with ADHD as a young kid. Interesting

  14. This article was no more informative than the title. For any actual data on the study, read the study published in Nature – though of course more than the abstract will require a subscription- lol!

  15. I know some people are against a cure, but as a mom to a severely autistic child, I would love to cure my son. The pain I go through everyday not being able to communicate with my 6 year old is unbelievable. He also has epilepsy, and he Doesn’t understand why he’s always in the hospital. He’s a very sweet boy, loves hugs and kisses, but his face is always bruised from slamming it into walls and floors. Removed dairy, eggs, dyed, gluten, tried nemecheck protocol, etc and nothing helped besides gluten and dye removal, but he still engages in extreme SIB. He breaks windows to elope, we’ve invested thousands into sensory toys and backyard activities, but everyday is still dreadful for him. He doesn’t get to tell mommy what he wants, needs, or feels. Please please please cure this. Not all autism is “Elon Musk” or “quirky personality”. ABA, PT, OT SLP daily have barely scratched the surface with my sweet boy.

  16. I hate how society classifies these as “disorders”…because if it were autistic adhd ppl made societal expectations, then the disorder would fall upon neuro “typical” ppl. I think of it as just a quirk or personality trait.

  17. I would like to see more research in Autism from child birthing perspective. Particularly when women are experiencing birthing complications; perhaps pushing at the wrong time and not fully dialated therefore causing distress and restricts oxygen to the unborn baby.

  18. Being a person of both autism and Adhd. Is RNF213 gene present?

  19. I am shocked that this is news to many. Sadly it is not in the career interest of journalists or scientists to find out why all these mutations are happening.

    here is a 2007 study I randomly picked from a google search of “de novo and autism”

    2007 Apr 20;316(5823):445-9.
    doi: 10.1126/science.1138659. Epub 2007 Mar 15.

    Strong association of de novo copy number mutations with autism

  20. Eugenics is a serious concern for us (I am Autistic and have ADHD), especially for Autistic people considering the largest Autism organisations like Autism Speaks have most of it’s board members investing their money in the CURE of Autism. Follow the money and you’ll see Eugenics is alive and well, and a very valid fear for us. But really all of us should be afraid; without Autistic people, we would be so far behind where we are today as a civilization. We are a gift, not a “risk” or “disordered” like this article mentions (very disappointing and outdated). Autism is not a disability, it is the world that’s been built around us without our consideration that disables us. This is why I’ve refused to get DNA testing because I can’t be a part of something that could end my people’s existence.

  21. In general I don’t like that any difference that is in the minority is usually labeled as a disorder. I am ADHD with autistic characteristics. There is always the possibility that someone will try to make is normal with an rna vaccine or something like that. Some may welcome it, others would call it Eugenics. I think this is important work. It is ever a problem in science to explore just to see the product of that exploration become a horrifying solution. I would caution science to use a less biased label. Someday the minority configuration might become the majority and if we fix it, then evolution will pass us by.

  22. I am curious to how many women have participated in this test. Many women in their 30s are now being diagnose with either ADHD, Autism or both. This is because the test is designed for boys and males because it looks different in females. I was wrong diagnosed for 8 years with BPD and now waiting for test after researching into my childhood testing that was done. To discover I have Auditory processing disorder, Cognitive processing disorder and mild intellectual. I had done my own research and truly believe I have both ADHD and Autism that went undetected my whole life and now being discovered at the age of 35.

  23. They aren’t disorders and even though they know they aren’t, they refuse to change the label in DSM5.

    Those people have a disorder due to discrimination. Eugenics at work.

    Too many tests are based on gender norms, not even just being different. We need more time and money to INCLUDE differences, not try to figure out why they are different. We are realizing many more are autistic. Time to accept that there isnt 1 way to be and it’s also socialized nonsense. Its taught.

  24. I’ve got both, only diagnosed in later life. Turns out most of my friends are some kind of ND, so maybe we just find people on our wavelength and breed and then you end up with both. I’m a successful professional, so it clearly didn’t do me any harm…

  25. Wanda Ivette Balines | November 9, 2022 at 10:31 am | Reply

    My daughter has autism and just just recently (she’s 15) got diagnosed with ADHD. Medication has been prescribed but she’s extremely well behaved and love to be alone. Needless to be said I need to know and read more about ADHD because I don’t understand that diagnosis. Aaron, your comment made me think you are a good source of information. Thank you.

  26. Let’s address the elephant in the room shall we? At 57 I have witnessed a lot. How many kids were on meds in the 70’s… In the 90s big pharma realized they had a untapped market.. children.. if you can’t understand why a kid is so jumpy etc… Had to be a problem.. born Adderall and the lot.. by the 2000’s it got where regular pediatricians and Drs were prescribing the meds that killed our kids creativity.. kids are mello.. teachers don’t have to do recess.. it got to where teachers were prescribing it.. tell your Dr he has ADHD.. and they listened… No testing.. it’s important to remember that in the 90’s the playstation came out.. I was a true ADHD kid who grew up in the 70’s.. I got hit alot and busted for forgetting stuff.. alot of wimping on the backside of the head.. I was diagnosed when I was in my 30’s.. I would go on to have 3 more kids and 1 is a true autistic.. my son went to a developmental Pediatrician who taught me a lot.. first of all there is no MAGIC pill.. self awareness is hard to teach.. I researched and asked questions.. here is what I learned.. kids don’t exercise anymore.. obese is up.. vitamin d levels down.. first of all kids who can sit at a PlayStation for hours playing Call of Duty does not have ADHD.. Autism either.. my son is 100% cured.. self awareness.. when he was little we used buzz words to let him know he was out of control.. we would holler “getting wild” and it was a verbal command to let him know to calm down.. the hardest was bullies.. so when he hit elementary school and had friends I created the musketeers and they always had each other’s back.. and the high underdogs.. it stopped bullying.. each child is different so only you can figure out where your child’s wires are crossed and uncross them…as a paradigm of hope.. my son is 19 now.. graduated with honors.. had his own apt living 5 hours away from me.. and has his license.. bought his own car and is self sufficient and doing well… Not a disabled kid.. had a awesome job making a grand a week.. they can be totally self sufficient and successful.. doping your kid up is not a answer.. although he like pot.. we found it helps with his stress.. He is his own man now and I cut that cord and wow he is flourishing on his own.. happy antidote’s from a happy mom..

  27. Vaccines are deliberately causing most problems. That’s what keeps big pharma, the medical field and so called experts in business. We know now.

  28. @ Stephanie – Although you do have some great observations, as An Autistic woman diagnosed at age 30 and with ADHD at 17, married to an Autistic man and have two Autistic Children and as an RBT + Autism Center Director.. An individual can ABSOLUTELY truly have Autism AND/OR ADHD and still play video games for hours at a time. Its a common misconception that ADHD means you are always going to have deficient focus. Thats not the case. Its just as common to HYPER fixate on subjects especially in the Autism community with Special Interests. ADHD folks are dopamine seeking and alot of them get that stimulation they seek sitting in front of a TV unfortunately because they are designed that way for a reason to market and hook their target audience. Think of it like the Brain being a Casino, trapped inside with no natural light, all the sounds are overwhelming and repetitive, the sensory haze of cigarette smoke, the flashing lights. Its Sensory Hell for Some, its ADDICTING to most. Now put them in front of something they don’t have interest in, and they TRY to focus, they may truly not be ABLE to focus the way they could on the game or whatever they are fixating on–They still have ADHD or Autism. I could read Harry Potter for 8 hours straight without even getting up to eat but if i didn’t like an author i would read the same sentence several times in a row and absorb literally NOTHING yet had a college reading level by first grade. Meds won’t fix anything. You’re right, its self awareness that makes the most impact outside of specific Therapies. Autism can be VERY Disabling to a person one day and they could have a High Functioning day the next. It depends on what is going on in their lives like anybody else but they Sensory issues we experience are talked about so little. Just because I am functioning in Society without Supports doesn’t mean I am not “disabled” the two diagnosis present their own strengths and struggles. I’m highly intellectually gifted but I do best in public with my service dog. I also am Chronically Ill– my state is not static as many people with Autism and ADHD experience similar fluctuations even without adding Lupus to the mix. On my Good Days, in which I need no supports and don’t feel like hell, even with a Stable Career and Family- I am still and will always be disabled. That is not to say we are NOT CAPABLE of doing things. But we face different challenges and need the understanding that just because I could do it yesterday or 2 hours ago doesn’t mean I can do it now. Neurodivergent people are the Future, we just have to remember how FRAGILE that future can be and it rests on every decision in the present. 🙂

  29. Its very commmon in Nigeria so I doubt it

  30. I agree with Jess.

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