NEW PATTERN OF RISK: A new theory explaining the genetic underpinnings of autism states that in some families, a male child could have as high as a 50 percent risk of developing the disorder.
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In work that may one day lead to earlier detection of children at risk of developing autism, a team of scientists has devised a genetic model for the enigmatic disorder. The two-tiered theory integrates families with one or more autistic children.
An estimated one in every 150 children born in the U.S. develops autism, according to the Centers for Disease Control and Prevention (CDC); it is four times more prevalent in boys than in girls. The condition is characterized by cognitive deficiencies and symptoms ranging from antisocial (not responding to one's name and / or avoiding eye contact) to obsessive, repetitive behavior. The most popular theory about its genesis is that there are flaws in several genes passed down through generations of a family that culminate to predispose a child to the disorder, especially if exposed to certain environmental factors such as toxic chemicals or a lack of oxygen at birth.
"People thought there was this uniform risk—if you have an autistic child, then there's some uniform, but fairly low, risk that you'll have another one," says Michael Wigler, a professor of genomics at Cold Spring Harbor Laboratory (CSHL) in Long Island, N.Y., and senior author of the new model described in Proceedings of the National Academy of Sciences USA. "None of the population geneticists, in my experience, had thought that there might be two classes of families: low risk and high risk."
Wigler's rethinking of autism's cause stems from an exhaustive analysis of risk based on a database of families with more than one autistic child. (The Autism Genetic Resource Exchange, or AGRE, manages the database.) The team determined that most cases of autism arise from novel, spontaneous mutations passed down from one or both parents, resulting in large gaps in a person's genome often encompassing several genes, which are then disrupted or inactivated. (This loss of genetic code—known as copy number variation—results in an offspring receiving only one of the standard two copies of a gene, which could cause an insufficient amount of protein to be produced by those genes.) In most instances, this mutation will result in an autistic child. However, in some cases—more likely in girls than boys—the recipient of this mutation will not produce any symptoms.
"When that child matures and becomes a parent, they have a 50 percent chance of transmitting … [their mutation] … to a child that might not be as lucky as they were, especially if … [its] … a boy," Wigler says. "So, they will be transmitting this with close to a 50 percent frequency—and that is the source of the high-risk families."
Wigler says that the team will continue to update its model as new figures are added to the AGRE database and try to gain new insight into the mechanism that gives girls greater resistance than boys. "To understand that [disparity] at a molecular or genetic level would be very important, because you could theoretically treat kids … you could detect something early and intervene," Wigler says. "I view it as the most important thing to understand."
Maja Bucan, a professor of genetics at the University of Pennsylvania, says that the new autism model is a creative way to interpret the familial data. "It's important to come up with new theories and then just test them once we have more data," she explains. "I don't think we have enough data [yet] to say whether this theory is right or wrong."
According to Wigler, the new model "certainly changes the way you think about autism. The paradigm shift is … something can be genetic without being heritable. The field has ignored the contribution of spontaneous mutation for a whole range of things that matter a lot to society," which, he adds, includes schizophrenia and morbid childhood obesity.
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6 Comments
Add CommentMy comment to Michael Wigler; after reading your most recent theory on Autism
Reply | Report Abuse | Link to thisspontaneous mutations, and your last statement "sometimes you have a problem, and people don't see the solution- because they are not looking in the right direction"....has any one out there really studied any mutations in females when they are on the pill?
I have always believed and still do, that medicine is not a generic equivalent of one size fits all. I believe with all my heart and mind that each of us is an individual made up of very complex genes, blood type, and weight. We each have our own formulas. When you have the right formula of your self with all of these given factors, then and only then will you be able to develop whatever is needed for the individual to use that has had a mutation, and immune attack! Therefore, my theory is also with regards to the pill, the chemical formula to withhold female reproduction is also mutating sporadically in each person's formula by which it clearly causes genetic mutations..breast cancer, autism, etc...
Think about this thought..????
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Edited by Hilton's Thoughts at 03/10/2008 5:14 PM
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Edited by Hilton's Thoughts at 03/10/2008 5:15 PM
There may or may not be something to what Hilton's Thoughts says, but for myself, this does not hold true. My wife has never been on the pill and stopped all medications during her three pregnancies. Our first child, a boy, is Autistic. The other two, a girl and a boy, while not Autistic are developmentally delayed. Ofcourse when we took our oldest in for his 2 year old shots and then over the course of two weeks he went from an engaging active, albeit developmentally delayed in speech, toddler to full on Autism, we decided not to take the other two in despite repeated reassurances that the vaccines are safe. Personal experiance tells us it's not so, and it's definately not worth the risk. My theory is that these children may be geneticly dispositioned towards Autism and that certain environmental factors may set it off. With my youngest two children being developmentally delayed, I'm not going to subject them to the environmental factors that apparently set off my oldest to be Autistic. To tie in with what Hilton's is saying; the vaccines may be "safe" for those not predispositioned to be autistic, it again may not be safe for those who are. One size fits all medicine may be doing a tremendous amounts of harm.
Reply | Report Abuse | Link to thisWhy the dramtic increase recently in autism cases? Genetic mutation ok. Increase in genetic mutation? Is autism on the rise in USA only or globally? Could genetic mutations be caused by increase in UV radiation or perhaps increase in radioactivity from industrial or military use in the environment? Genetic mutation in one or both parents from environmental problems to an autistic baby? Is somebody on top of this?
Reply | Report Abuse | Link to thisI have no doubt that genetics plays a role in autism. I also have no doubt that there is something in the water so to speak. I can't prove that autism and vaccines are linked. The medical community has "proven" that there is no link between autism and vaccines without taking a measure of the control group - the unvaccinated population's autism rate. Their proof is statistical and from a statistics standpoint claiming proof without a control group is silly.
Reply | Report Abuse | Link to thisMichael Wigler, I want to tell you I am autism pateient because of my Genes(DNA). If you need I am ready to give my self for reaserch.
Reply | Report Abuse | Link to thiswell my son at 13 years old can not speak a word ,is in diapers, and spoonfed , so he is for sure severely autistic, is it a gene that is definite- but the BIG LIE is that there's no proof vaccines did this to these kids ? There's RTONS of proof just open your eyes and read the meidcal literature! This is the BIGGEST LIE of the century or maybe even ver told our the WORLD...it was ...the vaccines. Period. susan in calif. Parent advocate and Dr's daughter
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