Aspies For Freedom

Gene For Brain Connections Linked With Autism

      By Maggie Fox tinyurl.com/32b7ny <http://tinyurl.com/32b7ny>

      Reuters - A gene that helps the brain make connections may
underlie a significant number of autism cases, researchers in the United
States reported on Tuesday.
      Disruptions in the gene, called contactin 4, stop the gene from
working properly and appear to stop the brain from making proper
networks, the researchers reported in the Journal of Medical Genetics.
      These disruptions, in which the child has either three copies of
the gene or just one copy when two copies is normal, could account for
up to 2.5 percent of autism cases, said Dr. Eli Hatchwell of Stony Brook
University Medical Center in New York, who led the study.
      "That is a significant number," said Hatchwell.
      "Generally the mistake that people make is they are looking for
one unifying cause for autism, and there is no such thing and there
never will be," Hatchwell said in a telephone interview.
      He said his finding adds to the list of potential tests for
autism, and perhaps treatments for a range of conditions known as autism
spectrum disorders.
      Hatchwell's team tested 92 patients from 81 families with autism
spectrum disorder and compared them to 560 people without autism.
      They did a whole genome analysis, looking at the entire DNA map,
and found three of the patients had deletions or duplications of DNA
that disrupted contactin 4.
      They were all inherited from fathers without a history of autism,
which can cause severe social and developmental delays and even mental
retardation.
      This may seem like a small number but millions of people have some
type of autism, Hatchwell noted. The U.S. Centers for Disease Control
and Prevention estimates that 1 in every 150 children has autism or a
related disorder such as Asperger's syndrome, which is marked by often
mild social awkwardness.
      "Autism is a syndrome. These individuals have all been grouped
together as having the same thing. There will be many, many dozens if
not hundreds of different causes," he said.

Mutation Present At Birth
      Contactin 4 is involved in the development of axons, which are the
long strings that connect one neuron to another. Other disruptions of
this gene are known to cause developmental delay and mental retardation.
      The genetic mutation is present at birth, Hatchwell said.
      "In each case a father who was reported as normal had the same
thing," he added.
      "This happens in genetics all the time. Often there are cases in
which someone is reported as normal. They pass it on to their child, who
has severe disease."
      It could be the fathers had mild Asperger's or some other
condition that was never diagnosed when they were children. Hatchwell
noted that parents today in the United States are far more likely to
seek a diagnosis for autism spectrum disorder in their children than
parents were in past generations.
      This is controversial, with some advocates and experts saying
autism and related disorders have become more common in recent years,
and others saying there is no evidence this has occurred.
      "My personal view is that it is not becoming more prevalent," said
Hatchwell. "If a parent has a child with some sort of learning problem,
if they get labeled as autism they get all sorts of help at school," he
added.
      Hatchwell has helped found a biotechnology company called
Population Diagnostics Inc. to develop DNA based pre-symptomatic and
early detection tests for autism, Alzheimer's, Parkinson's, Type 2
diabetes and other genetic diseases.
      In 2004 researchers at Yale University found one child with
developmental delays who had a deleted copy of contactin 4. In January,
they and two other teams linked a gene called contactin associated
protein-like 2 with some cases of autism, and a third team found a
stretch of DNA on chromosome 16 that they said may cause 1 percent of
autism cases.

Yet another small genetic marker... only 2% of autism cases, but if they find enough of these sorts of genes it could begin to account for a lot of us. What I wonder, though, is why they didn't check a lot of NTs and compare their genes--for all they know, there are a lot of NTs with that same gene, and it isn't diagnostic at all.

I guess I’m confused here. Am I understanding the art of genetic research properly?

They found a few autistics who shared a genetic anomaly. There were a few more with a different genetic oddity discovered elsewhere, and some other research that thinks they’ve got 1% nailed down.

What am I missing? How do they know that this shared difference has anything to do with autism? How do they know it isn’t a shared proclivity toward Alzheimer’s, or a narrow urethra?

And do they know if any NON-autistics get these genes?

I hope they don’t just lump them all together and let people base their prenatal tests on this stuff. Who knows how accurate it is?

Sheesh.

"These disruptions, in which the child has either three copies of
the gene or just one copy when two copies is normal, could account for up to 2.5 percent of autism cases"

I think this part is saying NTs have 2 copies whereas autistic children have one or three.

But only 2.5 percent of the autistic children :-/

And I'm not sure how having - or not having - them is definitely connected to autism.

Besides, there doesn't seem to be any info on what quality of life those with the deletions (or additions) have compared to people who don't have (or do have) them. So, if they're going to be part of the list of markers, I don't see how a prenatal test is supposed to tell how negatively the autism will affect thyem.

You don't suppose they'll ignore that question, do you? ;-)

I dont recall there being mention of prenatal tests. Those are good questions

Basically, that's the reason for genetic research into autism - to develop a pre-natal test.

Just imagine how much good could have come about if this funding was pumped into support services instead...

On days like this I feel like I ought to have a kid with an Aspie guy, just to pass on the genome...

I definately agree that the money would be better spent on support services.  
I didnt realize that genetic research is solely to develop a prenatal test.

I tend to think that a lot of the scientists working away in their labs on these pretty obscure research studies are passionately interested in their particular field of study for its own sake and aren't particularly concerned about its practical application.  Mind you, the funding has to come from somewhere, but a lot of the lab people won't be involved in the funding fights.

What these people seem to be saying is that there are possibly hundreds of genetic anomolies which may or may not be connected to autism.  I suppose the more they find the less likely it is that a definitive pre-natal test will be possible....?

Or am I being overly optimistic and over-simplifying things here?

I think the actual people doing the genetic research are mostly doing it for curiosities sake - but the reason they get the funding is to work towards a product, and about the only product that can come from genetic research is pre-natal testing.

If asked, they would say that they aren't doing it to develop pre-natal testing - But if pressed into what it would be used for, they would have to concede that pre-natal testing is what it would be used for.

Hey, that was nearly a SNAP!