Posted on 07/10/2008 5:17:01 PM PDT by neverdem
Genes Missing in Autism Needed for Learning-Triggered Brain Growth
Surprising findings from a gene study have set the world of autism research spinning on a new axis.
The new study shows that many of the different genes linked to autism -- and many of the new autism genes discovered in the course of the study -- are part of a network that allows a child's brain to build new connections in response to experience.
The good news is that a surprisingly large number of these mutant genes affect the on/off switches that control experience-triggered brain development. That's much better than missing the genes themselves, says study leader Christopher A. Walsh, MD, PhD, chief of genetics at Children's Hospital Boston and an investigator at the Howard Hughes Medical Institute.
"We are encouraged that some of these mutations do not seem to completely remove the gene altogether, but instead disrupt its on/off switches," Walsh tells WebMD. "That does offer hope we may be able to figure out other ways of activating the gene."
It's a big deal, says Thomas Insel, MD, director of the National Institute of Mental Health.
"We can begin to think of autism as a disease of synapses, of the way connections are developing in the brain," Insel tells WebMD. "This is really quite intriguing. It adds another region for science to go after to look for new targets for either autism treatment or prevention. It is a very important step."
Autism is a spectrum of different disorders ranging in severity and in symptoms. But all autism disorders have certain things in common: impaired social interactions, impaired communication, and stereotyped interests and behaviors.
The new findings offer a unifying theory, suggesting that many forms of autism result from specific defects that affect a child's ability to learn and remember.
Genetics plays a major role in autism. The mutations that cause fragile X syndrome and Rhett's syndrome result in autism. But unlike diseases such as cystic fibrosis, the vast majority of autism cases can't be traced to a single mutation. Instead, a growing number of different genes have been linked to a growing percentage of autism cases.
"We still don't understand the underlying genetics for more than half the kids with autism, so we have a long way to go to understand that, and to understand what non-genetic factors might also contribute," Walsh says. "We know genetics is very, very important in autism, but we don't know whether it is the whole answer or not."
The Walsh team's findings are "really exciting," says Margaret A. Pericak-Vance, PhD, director of the Miami Institute for Human Genomics. But she, too, notes that it's far from the end of the search for the causes of autism.
"Autism, even though it has a heritable component, is a complex disease that will take a lot of different approaches to decipher," Pericak-Vance tells WebMD. "It will not be one-stop shopping. We know there is no single major cause and no simple answer."
Pericak-Vance predicts that researchers scanning the entire human genome for autism clues will soon be announcing more "exciting" results.
Crucial to the Walsh team's findings was the collaboration of scientists in Jordan, Kuwait, Oman, Pakistan, Qatar, Saudi Arabia, Turkey, and the United Arab Emirates. These researchers enrolled 104 families in the study, including 88 families with marriages among cousins. That was an important factor, as rare or recessive genes occur twice as often in such families.
But also crucial was a chance meeting between Walsh, a geneticist, and fellow Children's Hospital Boston/Harvard researcher Michael E. Greenberg, PhD, a neuroscientist studying how the brain changes as it learns.
"When we talked to each other, we realized, gee, a lot of our genes that are involved in autism are also their genes that are involved in learning in the brain," Walsh says. "There is nothing more powerful in science than these kinds of serendipitous collisions between people working in related but somewhat distinct fields."
Walsh and colleagues report their findings in the July 11 issue of the journal Science.
(Just found out your child has autism? Come meet other parents who understand at WebMD's Autism Support Group.)
Ping
Shhhh, don’t tell Jenny McCarthy.
Now maybe the parents will get their kids vaccinated and not subject them to all the diseases that kills more than autism affects.
It is so weird you posted this, I was just reading about today and one website said autism affect 1 in 166. That seems really high.
Also, another study showed that autism increased at the exact percentage that mental retardation decreased. Apparently there are more funds for autistic children than retarded children.
Mental retardation has decreased because most babies with Down's Syndrome are aborted.
Food for thought:
The best evidence is that pregnant mother are massively deficient of vitamin d. The newborn is then given mother’s milk (also vitamin d deficient) or cow’s formula which is inadequately d fortified. Over 80% of autistic kids show evidence of allergic reactions (titer) to bovine milk proteins and over 50% show evidence of allergic reactions to wheat gluten.
It would appear that an auto-immune, vitamin d deficient state is precipitated by allergic reactions to significant food proteins (bovine milk and wheat gluten).
I certainly saw it in my own grandson, who was 2 1/2 when first diagnosed. It is remarkable how the brain can build new pathways.
This is why early diagnosis is SO important.
Spray Gun Shoots Adult Stem Cells Onto Wound
FReepmail me if you want on or off my health and science ping list.
Does anyone know what the statistics regarding autism in Europe?
Incidence
It's a little old, but the source appears to be reliable. Divide 10,000 by 60. It's same as 1 per 166.
Here's two handy definitions used in epidemiology.
Incidence incidence the rate at which a certain event occurs, as the number of new cases of a specific disease occurring during a certain period in a population at risk, in contrast to prevalence. P.S. It's usually the annual rate.
prevalence rate the number of people in a population who have a disease at a given time; the numerator is the number of existing cases of disease at a specified time and the denominator is the total population. Time may be a point or a defined interval, and is traditionally the former if unspecified.
What the St. George's website calls incidence I would have called prevalence. Otherwise, it looks like a good reference.
FWIW, somewhere I read ASD is pretty uniform worldwide. I think the claim is suspect. With the exception of Asperger syndrome, it appears to be a very heterogenous genetic problem defined only by behaviorial similarities, and influenced by the environment in ways mostly unknown, IMHO. Gluten enteropathy seems to be an interesting exception to the latter. I glanced at an interesting paper discussing allergy to latex proteins before I stumbled upon the St. George website.
Neverdem, autism recognition has only become common in the last few decades. Is it that we’ve always had the same numbers of autistic children and didn’t recognize it? That would seem odd since the symptoms are rather unique. I’m just wondering because it would be good to know if the anti-innoculationists have a point, or if it’s simply something we’ve always ‘swept under the carpet’ and said the kids were just weird.
That's certainly possible, but I don't know. We don't know what we don't know applies as much about the past as it does to the present.
We have psychologists and psychiatrists assigning functional diagnostic categories by how many behavioral symptoms are satisfied in Autistic Spectrum Disorder, IMHO, from the relatively benign Asperger Syndrome to the profoundly severe Pervasive Development Delayed, or however PDD is translated.
Some of this is genetic inbreeding as the story attests. How much is the result of environmental insult, spontaneous mutation or an epigenetic effect, I don't know.
I’m just wondering because it would be good to know if the anti-innoculationists have a point, or if it’s simply something we’ve always ‘swept under the carpet’ and said the kids were just weird.
They are still making the diagnoses with all of the vaccines coming in unit doses that are thimerosal free. Only the annual influenza vaccine that comes in multi-dose vials contains thimerosal.
Autism Bump
Does this "inclusion" somehow skew the study?
"When we talked to each other, we realized, gee, a lot of our genes that are involved in autism are also their genes that are involved in learning in the brain," Walsh says. "There is nothing more powerful in science than these kinds of serendipitous collisions between people working in related but somewhat distinct fields."
Gee, I'm mystified: why wouldn't the genes involved be related to "learning in the brain?"
I'm not a geneticist, but what makes you ask that? There's so much they don't know about what's going on with genetics, that when you can match traits to the various changes, you finally gain some insight.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.