LONDON (AP) – Children with attention deficit hyperactivity disorder are twice as likely to have missing or extra chromosomes than other children – the first evidence that the disorder is genetic, a new study says.

British researchers compared the genomes of 366 white British children from 5 to 17 years old with attention deficit hyperactivity, or ADHD, to those of more than 1,000 similar children without the disorder. The scientists focused on a sequence of genes linked to brain development that has previously been connected to conditions like autism and schizophrenia.

In children without ADHD, about 7 percent of them had deleted or doubled chromosomes in the analyzed gene sequence. But among children with the disorder, researchers discovered about 14 percent had such genetic alterations. Scientists also found that 36 percent of children with learning disabilities in the study had the chromosomal abnormalities.

“This is the first time we’ve found that children with ADHD have chunks of DNA that are either duplicated or missing,” said Anita Thapar, a professor at the MRC Centre in Neuropsychiatric Genetics and Genomics at Cardiff University who was one of the study’s authors.

She said the findings are too early to affect diagnosis or treatment and are only applicable to people of European Caucasian descent because studies have not been done yet on other ethnicities.

The condition is estimated to affect millions of children around the world, and scientists have long thought the disorder has a genetic component.

U.S. experts estimate that ADHD affects from three to five percent of school-age children in the United States. There are no figures for developing nations.

The study was paid for by Action Research, Baily Thomas Charitable Trust, the Wellcome Trust, Britain’s Medical Research Council and the European Union. It was published online Wednesday in the medical journal Lancet.

Peter Burbach, a professor of molecular neuroscience at University Medical Center Utrecht in the Netherlands, was surprised some of the genetic defects found for ADHD were identical to ones for autism and schizophrenia. He was not connected to the Lancet research.

“There’s a great chance the environment is modifying these genes,” Burbach said, adding the genes could lead to several brain disorders, depending on things like the child’s upbringing and other genetic factors.

He also thought scientists might eventually be able to reverse ADHD.

“This is not a structural abnormality in the brain, it’s just the last phase of development that’s gone wrong,” he said. “It could be the brain just needs to be fine-tuned.”

Philip Asherson, a professor of molecular psychiatry at the Institute of Psychiatry at King’s College London, said the study only dealt with a subset of people with ADHD and said the environment should still be considered a cause. In the case of some Romanian orphans, Asherson said there was proof that severe deprivation at an early age can lead to ADHD or other neurological problems.

Asherson said the medical world was still years away from being able to correct ADHD.

“The study doesn’t tell us a lot about what’s going on in the brains of people with ADHD,” he said. “If we can find out more about these genes and how they affect brain development, that may give us inroads, but it’s hard to say when that will be.”

(Copyright 2010 by The Associated Press.  All Rights Reserved.)

Dr. Max Gomez

Comments (18)
  1. ADHD mom says:

    I’ve been studying psychology for 10 years and i’m the parent of 2 children with ADHD……i have it as well. Many people who posted on this article are simply ignorant. People with ADHD are not dumb, in fact they tend to have higher than normal IQ’s.

    1. DanTe says:

      You study psychology. That pretty much puts you into the stupid category. Especially since you’re too stupid to realize that you just supported my comment on genetic.

  2. matt mann 2 says:

    There is no such thing as ADHD! It is a pseudo-illness so that the drug companies can sell billions of dollars of ADHD medicine(legal speed), so that parent who refuse to discipline their unruly petulant children can now just give the kid a pill and pretend that the parent has actually done something. And the parent has. The parent has enabled bad behavior by the child, and rewarded it by giving the child a hit of speed. You people ought to be shot!

  3. Kindra says:

    I am the parent of a ADHD child, I have never been a drug user and my child is anything but an overindulged spoiled brat. He has never been allowed to use his ADHD as an excuse to get out of things. So if you don’t have a child with this disorder, then I don’t think you can open your mouth and speak of things you know nothing about.

  4. Stupidity says:

    Wow, what idots we have in this world. People shouldn’t make stupid remarks when they don’t know what they are talking about. DanTe and Truthsayer, have no clue. I guess they think their parents were idiots, that’s why they are.

  5. truthsayer says:

    Of course…two people who do drugs or have done drugs in the past have no idea what kind of child they will unleash on the world. Same with intelligence..two idiots are most likely to produce another idiot. But most of all, I believe those ADHD brats are overindulged spoiled children who should have been controlled when they were a few months old, not allowed to act out and catered to.

    1. Lynanne Ptacek says:

      I hope you do not have children, because you fit the child abuser/murder to a tee!! How can you say that a BABY, of two months old should not be able to “act out”?? A child should be able to cry or tell you what they think. YOU are an idiot for sure.

      1. DanTe says:

        At “two months old” and you already got your baby “diagnosed” with ADHD. Sure you’re not stupid. Sure.

        Do the gene pool a favor, stop spawning.

      2. Nick says:

        The sooner you DIAGNOSE, the sooner you can put your kids on meds. Than you can parade them around like a freak show to garner sympathy.

    2. kdc says:

      Or maybe before one speaks one should understand about what one comments on.

      1. Avie Lumpkin says:

        As human beings, we all deserve respect and dignity regardless of what OUR own conditions are,, is denying their own right to be treated as a wonderful creation. We have used DIS-ability for so long, that we over look the ABILITIES they do have. I amso sorry that your world has not given you enough expeience to use such judgements. Retired school teacher of many many students who were labeled with ADHD

  6. DanTe says:

    Everyone knew this already. You have two stupid people copulating and you’ll get stupid spawns. This is nothing new.

    1. Lynanne Ptacek says:

      That is a pretty bold statement to make!! I am well educated and have children who have ADHD. So “stupidity” has nothing to do with it. If you truly believe that then I hope that YOU do not have chilldren, because they willl have ADHD.

      1. DanTe says:

        Ok, you’re right. Let me rephrase it with scientific accuracy:

        You have two genetic rejects copulating and you’ll get defective spawns. This is nothing new.

    2. kdc says:

      Seem’s to be a harsh comment, maybe you are a product of your statement.

    3. khilton says:

      Obviously, you’re the genetic reject.

      1. Nick says:

        I love this. All these people piping in. Not one has any fact or scientific datum to add. And a few of you just parrot the old brainless “oh yeah? and you too!” bit. All you do is strengthen Dan Te’s position.


    4. Cheryl says:

      That’s why the world is in trouble because of IGNORANT people like you and your misguided statements show your ignorance.ADHD has nothing to do with a persons IQ.

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