Possible Autism Gene

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Possible Autism Gene

Post by Corlyss_D » Thu Feb 22, 2007 4:40 am

Deseret Morning News, Monday, February 19, 2007

Autism gene found?

U. helps group identify possible predisposition

By Lois M. Collins
Deseret Morning News

University of Utah researchers are part of a worldwide consortium that has identified a gene that may predispose people to autism.

According to research released Sunday morning, the gene, neurexin 1, helps the brain cells form connections that transmit nerve impulses. The findings, which are part of ongoing research, was funded by a national nonprofit organization named Autism Speaks and the National Institutes of Health. They were published Sunday in Nature Genetics.

The Autism Genome Project, which includes the U. and 50 other institutions in the United States, Canada and Europe, embedded 10,000 DNA markers on a silicon microchip, then used it to analyze genetic samples taken from 1,200 families with siblings who have autism. It was a challenge to amass because the chance a family with an autistic child will have another with the condition is only 5 percent, said Dr. William M. McMahon, professor of psychiatry at the U. and co-investigator at the U. with Hilary Coon, Ph.D. research professor of psychiatry.

"The network put together the largest sample ever assembled of families that have more than one child with autism," he said. "Multiple-incidence families are uncommon and to make progress understanding the genetics of autism, we have to pool these families with other groups. It is remarkable cooperation."

The result showed a strong statistical signal on the short arm of chromosome 11, exciting to the researchers because that region includes the neurexin 1 gene, which has been implicated in previous studies of autism.

The next step, he said, will involve looking for sequence changes in the neurexin gene code and other genes on chromosome 11 that are also possibilities. Neurexin's role in brain cell communication makes it especially interesting. "We believe autism is a disease caused by faulty brain connections and it's exciting to have linkage in an area where there's such a good candidate gene."

He said a study of autism in twins suggests genes are very important. When one identical twin has autism, 60 percent of the time the other does, as well, suggesting genetic influences on the disorder. "But it's likely that the genetic influences work in concert with environmental factors as triggers," McMahon said.

He likens autism today to the term "fever" in the 17th century. "We recognize the external manifestations of it, but there are probably many causes. It may turn out there are 20 genes or more and several environmental factors that work in concert."

Autism is a brain disorder marked by social, communicative and behavioral development impairment. A Centers for Disease Control and Prevention study published earlier this month found that Utah had the third-highest rate, 1 in 133, of 14 states studied.

McMahon said Utah has much to offer in the quest to understand autism, because of the popularity of genealogy and the Utah Population Database. It also has a long history with autism research. In the 1980s, the U. did an epidemiology study of autism, and it is now trying to reach that study's participants so researchers can test their genes and correlate genetic findings. The criteria for diagnosis have changed and researchers also believe some who did not then meet criteria to be diagnosed with autism now do. Those early participants can call 801-585-9098.

Among those they have already reached, they have found "some very good outcome cases — people who got married and have good lives and good jobs — as well as people with poor outcomes. We wonder if genes contribute to the natural history," he said.

They also hope to study environmental interventions, to see what could have gone right or wrong.

But he warned that recent discoveries do not promise quick answers. "I don't want to oversell genetics. I've been doing this 30 years and I wouldn't be surprised if it was unsolved in a decade, when I retire," he said.

E-mail: lois@desnews.com
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Post by BWV 1080 » Thu Feb 22, 2007 9:55 am

Interesting. Fortunately, as the article states, Autism's genetic makeup is complex and not something that can be traced to a single gene like Down's or Rhett's syndrome. This means that thankfully there will likely never be a reliable prenatal test that leads to these children being aborted. I listened to a researcher from Tx Children's Hospital last year who was examining ties with the same complex of genes that is responsible for epilepsy.


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