DISABLED LEARNING?: New research suggests that genes associated with autism may affect the biological process of learning.
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A new genetic analysis of large, inbred Middle Eastern families found that genes linked to a heightened risk of autism are crucial to a child's ability to learn.
A group of scientists, led by a team at Children's Hospital Boston, has pinpointed six new genes that may contribute to autism, a disorder characterized by asocial behavior, difficulty communicating and repetitive actions that affects an estimated one in 150 children born in the U.S. each year. They report in Science that all of the linked genes are involved in forming new and stronger connections, called synapses, between nerve cells in the brain, which is the biological basis of learning and memory formation.
"We're showing, on the one hand, that autism seems to have a large genetic component," says study co-author Christopher Walsh, chief of genetics at Children's Hospital. "But, the genes that are involved are actually those that are involved in responding to the environment and learning."
The findings, Walsh says, reinforces the importance of early diagnosis of autism and intervention, particularly behavioral therapy and learning in enriched environments through repeated activities. Performing these sorts of tasks may help strengthen cellular connections, compensating for the malfunctioning genes.
The researchers studied 88 families in which one or more children had been diagnosed with autism, and the parents of each autistic child were cousins. Marrying second and third—and even first cousins—is not uncommon in the Middle East, and by studying such families scientists were able to track recessive genetic traits (caused by mutations that only affect individuals with two copies of the flawed genes). Such traits occur far more frequently in inbred families than in others.
The team found a total of six mutations affecting genes that had previously not been linked to autism. The mutations came in the form of deletions, where part or all of both copies of the genes were missing in a child with the disorder. All of the genes are known to be involved in parts of the same process: creating and strengthening synapses.
Normally, when nerve cells (neurons) activate in response to an environmental factor (such as processing a new face or a new sound), synapses between two active cells change to provide stronger connections so the cells can pass on information more efficiently. As the brain develops, new connections are continuously formed among nerve cells, reinforced and, in some instances, broken as the brain starts to mature and divvy up its different functions to specific groups of neurons.
According to the findings, "All of the relevant mutations could disrupt the formation of vital neural connections during a critical period when experience is shaping the brain," says Thomas Insel, director of the National Institute for Mental Health (NIMH) in Bethesda, Md. To wit, most children are diagnosed with autism between the ages of one and three years of age.
Walsh says the team believes these deletions—which in most cases found here only remove some, but not all, of the DNA that makes up a gene—may mean that the genes can regain some of their normal function. In fact, some of these genes may just be switched off. "This presents the possibility that in some kids we could get the gene going again without necessarily having to put it back in the brain," he says.
Jim Sutcliffe, a molecular physiologist at Vanderbilt University in Nashville, Tenn., in a Science editorial notes that the majority of autism research is geared toward prenatal development, even though the brain continues to develop well after a child is born. "Experience and environmental input play an important role in subsequent development," he says. He calls the notion that learning in early life is disrupted by these autism genes "an intriguing proposal," but says that further research is needed to validate it.
Dan Geschwind, a neurologist at the University of California, Los Angeles, says that to test the hypothesis that autism genes affect synaptic strength, it would be important to examine the 20 to 30 other genes that have been implicated in autism and see which ones also play a role in strengthening neuronal connections. "If its a significant proportion," he says, "that would provide support for the hypothesis being put forward."
Walsh notes that many children diagnosed with autism tend to show vast improvement when they are placed in environments that allow them to practice learning repetitively. He says that these activities essentially train the neurons to make up for their lost function.
"Our work reinforces the importance of early intervention and behavioral therapy," he says. "The more we understand about genetics the more we understand how important the environment is."
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9 Comments
Add CommentThere are more than kind of autism and they are confused by writers. The kind that my family has is named Asperger's syndrome. The changes noted in this disease are caused by compression of the anterior brain.Some of us are exceptionally intelligent.
Reply | Report Abuse | Link to thisAnother variation is derived from dolichocephaly. This form of autism causes ADHD and is extremely common in Humans who are defined as the children of Eve in GENESIS.
So, reading between the lines, it sounds as though we had it right 50 years ago. Strict discipline, high expectations, repetition 'til they get it' and other standards that have disappeared from the home environment and educational systems, seem to be the exact solutions to which this data is pointing.
Reply | Report Abuse | Link to thisIn the 30 years I've been hearing about these 'syndromes', and with a grandson that was suggested to be autistic (like many 5-year-olds, he's just manipulative, not miswired), I have always believed these things to be more 'made up' than real. While I accept there are some forms of severe autism that are indeed of physiological origin, it is my opinion that many of the behaviorial characteristics attributed to autism (and especially ADHD) are really the outcome of lax parenting and the social experimentation of the educational system.
I'd like to see more study on this from sources that don't have a profit motive or a defensive posture in making more of these conditions than truly exists. There's too many apologists, too many drugs, and not enough authoritarianism in the entire child-rearing business.
In my opinion, our grandparents (and my grade shool principals) had it right.
SeekingTruths , glad you have an open mind. Fifty years ago you endured the discipline, expectations and repetition and you are OK and that must be the difference. So, you and your parents were exposed to the same environmental toxins, fast foods and processed foods, ate the same diet and had the same immunization schedule as your grandchildren do today. Didn't think so. All of these elements exacerbate the genetic predispositions to the conditions you describe.
Reply | Report Abuse | Link to thisGenetic research is great and is a piece of the puzzle. So are the home and school environments as you point out and the article's author added as an afterthought.
Having lived with family with ADD and Autism I can attest, it is much more than environmental and I am sure it is not purely a genetic aberration. We have used nutrition and structured behavioral methods to greatly improve behavior and performance.
To use a 50 year old term, you sound like the old sourpuss I had torture me in the third grade back in the 50's. I am grateful that my children and grandchildren don't have her methodology in their classrooms. I am also grateful for charter schools that give us the choice of "basic education" with the structure and repetition that help so many students thrive.
The question has not been answered...why the neurons don't work. Why is there no problem with the Amish who were not vaccinated? I guess we change science to protect the guilty.
Reply | Report Abuse | Link to thisThe findings of this study are interesting and do seem to support that individuals with ASD can learn and that their brains can change from experiences. The findings of this genetic study do NOT provide any guide as to the content of learning and how to teach individuals with autism. Discrete trial teaching and other therapies based on behavior theory are one approach to teaching skills. This is not the way we humans typically learn how to communicate, engage in reciprocal social interactions, and problem solve when faced with a novel dilemma.
Reply | Report Abuse | Link to thisTo follow-up on "bfreewithrp," you speak of inbreeding. The Amish have some of that problem also, but don't have the autism problem. Go figure. I think you have not dug far enough yet. Are you really searching for an answer or for a proof.
Reply | Report Abuse | Link to thisMy, soon to be, seven year old grandson's parents have no relatives in common unless you go back to Noah's children. Chase the genes, but no the inbreeding.
Reprogramming the brain such as crawling seems to have some promise in my thinking. It has worked for other problems.
Im wondering what, exactly, switched off means. It sounds to me like it could be a euphemism for damaged.
Reply | Report Abuse | Link to thisIt seems more than a bit absurd to try to find out which particular genes are more susceptible to being poisoned by mercury than others. But then, when the mercury exposure has been occurring to such a huge extent via childhood vaccination, its no surprise to see the most absurd ideas put forth by government researchers and the main stream media that covers their collective rear ends.
It also seems absurd to act as though this were news. Parents of children with autism have known of synapse damage for years. Visit here if youd like to see a video of synapse damage occurring after exposure to mercury
http://commons.ucalgary.ca/showcase/curtains.php?src=http://apollo.ucalgary.ca/mercury/movies/Lor2_QTS_300kb_QD.mov&screenwidth=320&screenheight=256
Rather than trying to find out which particular genes are most susceptible to being destroyed by heavy metals, it might make more sense to try to find out which particular genes ARENT.
Or, better yet, stop the exposure to the environmental toxins.
Robin Nemeth
http://www.wideopenwest.com/~r_nemeth/vaccine_flyer.htm
What I'm wondering is 'Why does it seem that most of the medical/scientific community only focuses on trying to find THE ONE smoking gun???? ' Why not further explore the educated belief that Our children begin with a genetic predisposition for this problem BUT it takes the combination of genetic weakness AND environmental factors for them to develop ASD? The environmental factors include MANY possibilities (only one of which is the vaccination schedule / thimerisol issue).
Reply | Report Abuse | Link to thisI believe the Amish previously referred to may have the genetic predisposition but have NOT been exposed to the environmental factors (vaccination, overly processed foods full of toxins & hormones, etc...)
As for 'SeekingTruths"...how can you without having a mind that's open to changing the mindset you've obviously had made up for many, many years? Autism is real and it is a spectrum disease which means that it will affect children in many different ways and levels of impairment. These things are NOT 'more made up than real' and I truly hope your grandson really is just manipulative...that way he won't miss out on help that would be needed & you won't have to change your mind.
Another problem with focusing on only one component to an issue is that, with the way this is put forth, now what about those people who will want to start calling our of our children derogartory names like 'inbreds'? I realize that the report says this only made it easier to isolate the genes...but there are those ignorant people everywhere who won't get that part of it.
I am a special education teacher and have worked with children with autism. 10 years ago, many children who presented with symptoms of Autism, were "labeled" Educable Mentally Handicapped. As the label "Autism" became more common, many children who previously were labled EMH, are now labeled "Autistic" as the funding for children with this label is more than the funding for children with EMH. Many parents would much rather have their children labeled"Autistic" than Educable Mentally Handicapped, or Mentally Retarded. So in order to get services to this child, psychologists will label the child "autistic" because parents will go along with this label, and the school funding is greater. At least the child will receive some kind of services that the parent will sign for. There is no research that proves that vaccines cause autism. No one knows for sure what causes Autism, but it would be great if as much money was devoted to the early intervention services for these children, as was spend on the "cause" debate. Early intervention is absolutely essential in providing appropriate services for each child. Every child with Autism is truly unique. Let's concentrate on identifying these children early ( 2 years old). Call your local school district to arrange for Child Find Evaluations in your area. Services start at 3 years old and they are free through your local district. If you are aware of a child who would benefit from a pre-school evaluation, please inform the parents about Child Find. The teachers of these children are SAINTS. They are effective, dedicated, and passionate about what they do. Rosie Broberg Special Education Teacher
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