Posted on 01/09/2008 7:58:35 PM PST by neverdem
Associated Press
A rare genetic variation dramatically raises the risk of developing autism, a large study showed, opening new research targets for better understanding the disorder and for treating it.
Research into the causes of autism has focused on genetic causes because so many families have multiple children with the disorder. Thus far, only about 10 percent of autism cases have a known genetic cause. Boston-area researchers estimate the gene glitch they've identified accounts for another 1 percent of cases.
They found a segment of a chromosome which has genes linked to brain development and various developmental disorders was either missing or duplicated far more often in autistic people. The defect was inherited in some cases, but more often the result of a random genetic accident.
The results from the Autism Consortium study, released online Wednesday by the New England Journal of Medicine, confirm those of smaller studies by U.S. and Canadian research groups in the past year. The consortium verified its findings by checking two other DNA databases.
"They really did nail it," said Dr. Andrew Zimmerman, director of the Kennedy Krieger Institute's Center for Autism & Related Disorders in Baltimore, who was not involved in the research.
He predicted children newly diagnosed with autism or other developmental disorders now will be tested for this defect on chromosome 16 and that studies of many more DNA samples may reveal other autism-related gene variations.
Already, the findings are starting to be used to give some parents long-sought answers to burning questions: What caused autism in their child and how likely is it that any future children also would have autism, long known to run in families?
"We've provided very compelling evidence that this particular small stretch of the genome provides an important clue to the biological roots of autism," said lead researcher Mark J. Daly, an assistant genetics professor at Harvard Medical School and an investigator for the consortium, which includes researchers from 14 Boston-area universities and medical centers.
When the biological pathways involved are figured out, scientists can try to design drugs to target chemicals in the brain to treat autism, said Geraldine Dawson, chief science officer of the advocacy group Autism Speaks.
"I think chromosome 16 is now going to be a hotbed for autism research," said Thomas Lehner, head of the genomic research branch at the National Institute of Mental Health. "It gives us a very important lead."
Another study researcher, Dr. David Miller of Children's Hospital Boston, said the chromosome 16 variations increased the risk of autism a hundredfold. But he said the disorder must be due to a combination of genetic variations since there were cases of people who had the defect but didn't have autism.
Autism, a complex, poorly understood disorder, is characterized by repetitive behaviors and poor social interaction and communication skills. Research has mainly centered on genetic causes, and on whether it could be caused by the mercury-based preservative once used in childhood vaccines, which has been repeatedly discounted.
The number of children diagnosed with autism has risen in recent years to as many as one in 150 American children, but experts are unsure whether its prevalence really is increasing or the trend is due to a broader definition of autism.
For their study, consortium researchers scanned all 46 chromosomes from DNA samples from 1,441 children with autism or related disorders. They also scanned DNA from most of their parents and 2,800 other people, none known to have autism.
The researchers found a 25-gene segment of chromosome 16 was missing in five children with autism; none of their parents had the deletion. That shows that in some cases the genetic glitch is not inherited from the parents, but instead due to a random accident while an egg or sperm is being formed.
Another seven autistic children had a chromosome 16 duplication, but all but one had parents with the same duplication.
The researchers confirmed their findings by looking at DNA databases from Children's Hospital Boston and Iceland. The same defect was found in 1 percent of those with autism or related disorders. It was found in just seven of about 19,000 Iceland samples from people without the disorder.
On the Net: http://www.nejm.org
http://www.autismspeaks.org
http://www.autismconsortium.org
This is a parent's nightmare...
You may have to register to read it.
Interesting. I really don’t know that much about autism, but my new neighbor’s son is autistic, so I guess I’m about to find out a bit more. I would want to know more about the parents’ personal histories to see if there are any similarities - environmental or anything else.
Do you know offhand of any famous personalities in history who were thought to be autistic?
Hmmm. A generation or two ago, one of the anti-drug scare stories was that marijuana could cause genetic damage. How many of the kids with the genetic defect had a parent who had smoked weed?
I had that debate on another thread a day or two ago. Neither of us convinced the other.
I doubt it. I know too many people who smoked dope who have normal children. I don’t know if additives/pesticides play a factor now, however.
??????????????????
I'm am either missing something here or the writer screwed up big time. I would not call a correlation on such as small incidence.
Rumor has it that Steven Spielberg has Asperger's Syndrom, a form of autism. Also, I believe Einstein and Alexander Graham Bell are thought to have had Asperber's. People with Asperger's often have an ability (or disability depending on how you look at it) to hyper focus on things that interest them. They can become great success stories if they can focus in the right area for them.
My 7 year old grandson made a hole-in-one at our local country club last summer after only playing 2 or 3 times. He definitely has the ability to focus in on things, so much so that at first we thought he had a hearing problem. He sees in a very 3 dimensional way. If he can deal with the problems and focus in the right way, we think he will be an inventor or engineer of some kind.
I have a grandson with some problems, as well. He had a traumatic birth (his head got stuck in the birth canal and he swallowed amniotic fluid and developed pneumonia). He’s had problems focusing on instructions given. It’s almost like he’s someplace else and not listening, but when it comes to focusing on a project, especially building, mechanical arts, etc., he is a master.
I have a autistic daughter. Did alot of reading on possible causes for autism. If autism is just a natural genetic problem that was misdiagnosted in the past, then historical retarded kid rate should be at 1 per 150 (assuming autistic kids are lumped together with retarded kids). Our current combined rate of retarded with autistic kids per 1000 kids is much higher than past historical data. We are doing something in the modern life style that is triggering autism in kids who are prone to it that did not happen in the past. IMHO it is the preschool vaccines. It is not the mercury preservative, but in my opinion it may be the large numbers of vaccines givened to the child in such a short period of time and there are possible drugn interaction of side effects with a young child’s body which is undergoing rapid development (especially the brain). We are looking at up to 16 vaccines before the child enters Kindergarten and the states are still adding more required vaccines to the list. When I went to school over 40 years ago, I was givened only 7 shots for school admission. This theory comes from a new theory on the Gulf War Syndrome that struck our soldiers in the first Iraqi war. Soldiers were developing many symptoms that could not be narrowed down to one particular cause, however some military doctors are wondering if the huge multitudes of vaccines givened to the soldier in one day before deployment can be the cause (side affects interacting with side affects). I would like to see a state do an experiment and spread the vaccine schedule out or start eliminating vaccines against nonlethal child diseases and track the autism rate in the state.
IIRC, I believe this genetic anomaly is one of about ten associated so far with autistic spectrum disorders. From the link in comment# 1:
Replication in an Icelandic Sample
We observed that 3 of 299 subjects with autism spectrum disorder from Iceland carried the 16p11.2 deletion, a finding that was consistent with the 1% frequency observed in children at Children's Hospital Boston who had sporadic developmental delay or autism spectrum disorder (Table 5 of the Supplementary Appendix). One of these deletions was de novo, the origin of the second deletion was not known, and one was inherited from a father who had attention deficit–hyperactivity disorder (ADHD). By contrast, in a control sample of 18,834 subjects who did not undergo screening for a psychiatric or language disorder, only two deletions were observed — in other words, the deletion was observed more often in patients with autism by a factor of 100 (P=3.7x10–5). However, in a study of the same population by investigators at deCODE Genetics, this deletion was observed at a markedly increased rate in subjects with a psychiatric or language disorder. This study showed that the deletion was present in 1 of 648 patients with schizophrenia, 1 of 420 patients with bipolar disorder, 1 of 203 patients with ADHD (the father of a child with autism, as noted above), and 1 of 3000 patients with panic disorder, anxiety, depression, or addiction. In addition, 1 of 748 patients with dyslexia carried the deletion. Overall, in the Icelandic samples, the carrier frequency among patients with autism was 1%; the frequency was approximately 0.1% among patients with a psychiatric or language disorder and 0.01% in the general population.
“We are doing something in the modern life style that is triggering autism in kids who are prone to it that did not happen in the past”
I tend to agree with you on that point. Admittedly, I haven’t read up on the increasing number of vaccinations given at earlier ages, so I can’t comment, but certainly you could be right. Lifestyles have completely changed in the past 40 years and have become increasingly unhealthy for numerous reasons. An increasingly sterile and enclosed environment is setting us up for a big fall, I fear.
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also, she is a bit paranoid and hyper sensitive to criticism and will go on and on if you say something she doesn't agree with....
when she was little, she was relatively happy.....a loner though...she played with her brother a lot....
seems as she grew older, she withdrew more from other kids....paranoid of them .....she probably had a right to be since kids pick on anyone who is differant....
if I had only realized early on maybe I could have done school, etc differantly.....
He had to have someone with him constantly as he would walk off without knowing where he was.
I recall taking grandchildren to the zoo when he was a little guy. One person had to have hold of his hand or he would wander away. He wanted to go certain directions because he could read the signs as to what direction were the elephants, etc. Mom and dad had to keep their doors securely locked with high latches to keep him confined.
There are a few horror stories of him getting away.
Anyway, he has progressed remarkedly to where he is now ready for college and has been accepted at one of the top rated schools in the country.
He has also progressed socially to where he was a homecoming king candidate this year. He's a little geeky but his outlook is bright but he's come a long, long way. We would never have expected this considering the profound problems he had has a youngster.
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