A Genetic Clue to Why Autism Affects Boys More

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http://news.yahoo.com/s/time/20090520/h ... 9189975600



Among the many mysteries that befuddle autism researchers: why the disorder affects boys four times more often than girls. But in new findings reported online today by the journal Molecular Psychiatry, researchers say they have found a genetic clue that may help explain the disparity.


The newly discovered autism-risk gene, identified by authors as CACNA1G, is more common in boys than in girls (why that's so is still not clear), and the authors suggest it plays a role in boys' increased risk of the developmental disorder. CACNA1G, which sits on chromosome 17, amid other genes that have been previously linked to autism, is responsible for regulating the flow of calcium into and out of cells. Nerve cells in the brain rely on calcium to become activated, and research suggests that imbalances in the mineral can result in the overstimulation of neural connections and create developmental problems, such as autism and even epilepsy, which is also a common feature of autism.


"Our current theories about autism suggest that the disorder is related to overexcitability at nerve endings," says Geri Dawson, chief science officer of Autism Speaks, an advocacy group that provided the genetic data used by the study's authors. "It's interesting to see that the gene they identified appears to modulate excitability of neurons."


For the new study, researchers at the University of California, Los Angeles (UCLA), combed the genetic database of the Autism Genetic Resource Exchange (AGRE), a resource of DNA from 2,000 families with at least one autistic child. The scientists focused on the more than 1,000 genetic samples of families in which at least one son was affected by the disorder, prompted by the results of an earlier study using the same database, which identified a rich autism-related genetic region on chromosome 17 that contained genetic variants more common in boys than in girls. While nearly 40% of the general population has the most common form of CACNA1G, one variant of the gene was more prevalent in autistic boys, researchers found. "There is a strong genetic signal in this region," says Dr. Daniel Geschwind, director of UCLA's Center for Autism Research and Treatment and one of the study's co-authors. "But this gene doesn't explain all of that signal or even half of it. What that means is that there are many more genes in this region contributing to autism."


That's not surprising for a disorder as complex as autism - actually, a spectrum of developmental disorders involving impairment in language, social behavior and certain physical behaviors - with symptoms that range widely in number and severity. So far, studies have linked a handful of genes, all of which play a role in the way nerve cells connect and communicate, with autism spectrum disorders. It's likely not only that a large number of genes contribute to the disorder, but also that a different combination of genes - as well as unique interactions between genes and environment - are responsible for each individual case of autism.


So it's certainly a daunting challenge to begin teasing out the individual genes that may contribute to autism, as the UCLA team has with CACNA1G, but databases like AGRE make the job slightly easier. The next step will be to try to use known autism genes to help develop screening tools or early interventions. "We are going to have a much better understanding of the causes of autism over the next five to 10 years," says Dawson. "We're in a period of great discovery."

*bump*

Am I the ONLY one that looks at this and says *****************************SO WHAT!?!?!?!?*****************************************?????

I mean they looked at 1000 samples and found a variant that is in 40% of the GENERAL population, a MINORITY but STILL a large part, and one variant was MORE prevalent in Autistic males. Supposedly females don't have this gene that they MUST have because 1. it is on a chromosome they have and 2. it IS supposedly vital to calcium control which is vital to MANY things in humans. I would like to know what females are supposed to have instead. And they found that one variant was MORE prevalent in their sample. And WHERE did they gett the sample from?!?!?!?

BTW the 17th chromosome is one that BOTH males and females have TWO copies of! Usually sex linked problems are due to the 23rd chromosome(males are missing 1/4 of the copies of genetic material, so they have to depend on a copy that may have problems), or a feature on another that is somehow affected by sex. Male and Female brains DO operate on the cellular/neuron level in the same way.

Calcium is one of the LEAST appreciated minerals in the human body and perhaps the most prevalent. It is used for bones, teeth, maintaining PH, the brain, muscles, etc...

and I guess all Autistic people MUST be RH-!

They THEMSELVES say that there have to be other genes involved.

OK, ONE QUESTION! How many of their mothers had carrots?

They are as bad as those people that find that creature that they believe has human traits, and they think it is the missing link.

Can;t they find something that ALWAYS causes a problem, or NEVER shows up when there is a problem, and say WE FOUND IT, instead of using the old carrot theory?