Probing autism: Shown here is a DNA microarray. Each dot represents a specific sequence of donor DNA bound to DNA probes on the microarray. Bright green indicates an area where a chunk of DNA has been deleted, red indicates a duplication of DNA, and yellow indicates an area with no duplications or deletions.
Agilent Technologies
A massive study takes a major step forward in explaining the genetics of autism.
A specific structural variation on chromosome 16 dramatically boosts the risk of autism, according to a study published today in the New England Journal of Medicine. The finding--one of the most significant to date--permits the development of new diagnostic tests to identify children at risk, and could ultimately point to specific biochemical pathways to target in drug development.
"This is one of the single largest [influences] and most frequent genetic causes for autism identified so far," says Bai-Lin Wu,director of the Genetics Diagnostic Laboratory at Children's Hospital Boston and one of the senior authors on the study.
Autism spectrum disorder--or autism, as it is commonly called--refers to a group of developmental disabilities with wide-ranging language, social, and behavioral symptoms. The disorder is known to have a strong genetic influence, with up to 90 percent of cases thought to have a genetic component. However, because the disorder is linked to a combination of genetic variations, each playing a minor role, identifying specific genetic triggers has been difficult. Now new microarray technologies, which allow scientists to screen a million or more genetic variations in thousands of patients, are enabling the much larger studies needed to pinpoint these triggers.
In the new paper, scientists say that they used microarrays to scour the DNA of more than 2,000 individuals with autism. They found that deletion or duplication of approximately 500 of the same DNA letters on chromosome 16 was strongly linked to autism, accounting for about one percent of cases. "While that doesn't sound like a huge number, the fact that these people carry the identical spontaneous deletion or duplication would be incredibly unlikely to happen by chance," says Mark Daly, a geneticist at Massachusetts General Hospital's (MGH) Center for Human Genetic Research, in Boston, and at the Whitehead Institute, in Cambridge, and one of the study's senior authors.
The results were independently identified by three different groups--at MGH; Children's Hospital Boston; and deCODE Genetics, in Iceland--that are studying three different populations, giving added weight to the work.
The findings build on previous reports that autism is linked to genetic deletions or duplications that arise spontaneously, rather than being passed down through generations. In almost all cases, parents of the affected people did not carry the chromosome 16 variation.
One of the most immediate clinical benefits of the research will be the development of inexpensive diagnostic tests. "Because the variation occurs so frequently, you could directly test for the presence or absence of a duplication or deletion as part of standardized genetic testing for autism," says James Gusella, a neurogeneticist at Harvard Medical School, in Boston, who participated in the research. For example, children who show developmental delays but are too young to undergo clinical autism testing could be screened for this variation, allowing parents and doctors to prescribe intervention for those who test positive. "We will be able to find at-risk children early on so that language and behavior problems can be treated much earlier," says Yiping Shen, director of research and development at Children's Hospital's Genetics Diagnostic Laboratory, who was also involved in the work.
By creating animals with chromosomal abnormalities, they hope to learn more about how the disorders develop.
A chemical that alters chemical signaling seems to ease anxiety and other symptoms.
Compounds that show promise in mice with mutations may offer similar hope to humans.
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michael0156
1 Comment
Horrbile mistakes and generalizations
Quote from the article - "Autism spectrum disorder--or autism, as it is commonly called--refers to a group of developmental disabilities with wide-ranging language, social, and behavioral symptoms. The disorder is known to have a strong genetic influence, with up to 90 percent of cases thought to have a genetic component."
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1. Autism Spectrum Disorders (plural is correct) is a collection of several related, but seperately defined, disorders. Childhood Disintegrative Ddisorder, Asperger's Syndrome, Rett's Syndrome, Autism, and lastly Pervasive Developmental Disorder-Not Otherwise Specified. The author is apparently unaware of this differentiation or deliberately ignores it. A possible reason to lump all of the different afflictions under only one of the spectrum labels is that the referenced study's similar genetically "identified" cases were diagnostically different disorders. Whether or not that is the reason for the author's mistatement is unknown
2. Emily reports the that 2000 individuals with autism were studied. That is wrong. Only about half that number in the study had autism, the other half were controls. Some of the controls also had the "spontaneous genetic deletions", but did not have autism. Emily leaves that info out, while erroneously reporting TWICE the number of autistic subjects in the study.
3. Her reporting that "up to 90%" of autism has a genetic component is simply an uninformed statement or a deliberate deception. No text or reputable study makes such a claim. No one knows the cause of autism.
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Another quote "The DISORDER is known to have a strong genetic influence". Again the author refers to multiple disorders as if they are one AND makes a statement of fact about a strong genetic influence that is NOT known to exist, and is actually the point the referenced study is trying to gather information about. The author seems bent on proving a point by merely stating that it's a fact.
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I have been unable to find the author's Bai-Lin Wu quote even after removing [influences] and breaking the quote up into two smaller fragments. The only place this "quote" shows up is in this author's article
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What I have been able to find is a Business Week article on the same study which claims a new technique, CMA, is being pushed as a genetic test for autsm (now we see the influence of money enter the equation). This claim of improved genetic testing is based on CMA "identifying" 7% of autistic cases in the study. I believe that is a misquote by Business Week and that the reported percent was 1%
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Also in this Business Week article is a quote from Dr. Robert Marion, a pediatric geneticist at Children's Hospital at Montefiore Medical Center in New York City.
"In the vast majority of cases, we believe there is at least a genetic predisposition to autism, but the ability to identify a specific genetic cause has been very elusive," Marion said. "Part of that is because of the technology that's been available. A LARGER PART IS AT THIS POINT, WE JUST DON'T FULLY UNDERSTAND WHAT THE GENETIC MECHANISM THAT LEADS TO AUTISM IS."
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This directly conflicts with the Emily Singer's ideas and statements about genetic causes of autism. Also in the Business Week article it is revealed that The Autism Consortium is the major player in the quoted study's backing. This is a significant conflict of interest not reported in Ms Singer's article. The Consortium is HEAVILY tied to Merck, the largest maker of vaccines in the world, and Merck has a desperate interest in proving genes cause autism rather than vaccines.
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Vaccines are the only obvious correlation to autism and autism's meteoric rise in the past 20 years. NO OTHER HYPOTHESIZED EXPLANATION HAS ANY EVIDENCE ASSOCIATED WITH MORE THAN A FEW PERCENT OF AUTISM, WHILE VACCINES ARE ASSOCIATED WITH AUTISM OVER 95% OF THE TIME.
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In a 2008 CBS News interview Dr Bernadine Healy stated "Vaccines may cause autism" & "It's inexcusable that the proper research has not been done!". Dr Healy is a highly accomplished very intelligent mainstream doctor and scientist (Vassar summa cum laude, Harvard Med cum laude, intern and resident at John Hopkins, Director of The NIH, Chair of The Research Institute at The Cleveland Clinic, Professor of Medicine at John Hopkins). For her, in 2008, to make such a strong statement about vaccines needing to be studied as the cause of autism is a shocking call to arms.
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I feel Ms Singer's article is deliberately slanted, exaggerated & contrived, to unrealistically and falsely represent/support that genetics are autism's cause.
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There is MUCH more wrong with her article I could point out, but I feel the "errors" I have addressed are sufficiently egregious and that she should retract the article and apologize for publishing it.
Reply
Lee Veitch
1 Comment
Re: Horrbile mistakes and generalizations
I'm a parent of two children with autism - a 100% hit rate, if you like.
My son (first child) was fully vaccinated up until we suspected autism. Then his vaccinations were ceased completely, as a precautionary measure.
My daughter (second child) was never vaccinated - not even the standard hospital birth shots, as she was born at home.
She has autism anyway.
If vaccines are the cause, then the fairies vaccinated her in the middle of the night, because she certainly wasn't vaccinated with my knowledge.
For goodness' sake, stop blaming vaccines, and let's get to the bottom of this.
My studies (and believe me, I've studied!) suggest that autism is on the rise, that it is genetically based, and that the genetic weaknesses that have been dormant in our society are being activated by environmental factors. In most cases, probably NOT vaccines!
This isn't about blame, this is about fact, and finding a cure for our children. Every time I hear "vaccines did it" I want to scream - it just makes parents of kids with autism look like scientific dumbos.
There are other toxins in our world besides vaccines.
As an aside, I'm currently studying the links between familial atopy and autism, which are statistically significant.
Reply
Jstafura
2 Comments
Re: Horrbile mistakes and generalizations
Clearly the author of this comment is part of the group that attacks any claim that isn't tied to vaccines, something that has been debunked in several studies.
All they have done is bring back measles.
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