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【medical-news】美研究人员发现致孤独症风险增加
Mon Oct 16, 2006 6:05pm ET
By Maggie Fox, Health and Science Editor
WASHINGTON (Reuters) - U.S. researchers said on Monday they had identified a genetic mutation that raises the risk of autism and could also explain some of the other symptoms seen in children with autism.
Although autism and similar disorders can clearly run in families, theirs is the first study to find a definitive genetic link to the disorder, which affects as many as 1 in 175 U.S. children.
Dr. Pat Levitt and colleagues at Vanderbilt University in Nashville, Tennessee, studied 743 families in which 1,200 family members were affected by autism spectrum disorders, which range from fully disabling autism to Asperger's syndrome.
They found a single mutation in a gene called MET, which is known to be involved in brain development, regulation of the immune system and repair of the gastrointestinal system. All of these systems can be affected in children with autism.
"This is a vulnerability gene," Levitt said in a telephone interview. "There are not genes that actually cause autism. It raises the risk."
People with two copies of the mutated gene have 2 to 2.5 times the normal risk of autism and people with one mutated copy have 1.7 times the risk, he said.
The findings, published in the Proceedings of the National Academy of Sciences, offer a way to start looking for the actual causes of autism, Levitt said.
Autism can cause a range of symptoms, from fairly mild social dysfunction to severe and disabling learning and social impairments.
Researchers knew it could run in families, but the cause has been unknown. Children are usually diagnosed as toddlers, with parents often describing a sudden regression in abilities and behavior. There is no known cure.
Levitt said the mutation does not change the function of the gene, but changes gene expression -- how active the gene is.
Levitt says his team will now try to make a rat or a mouse with the same genetic mutation and use it to study what in the environment might cause autism in people with the mutation.
"It may be more than one thing," Levitt said.
"Let's say it is exposure to some chemical. It is a long list of everything from food additives to mercury to fertilizers. This will help."
QUESTIONS ABOUT VACCINES
Levitt said his study may help answer questions about links between vaccines and autism.
Experts virtually all agree that vaccines do not cause autism but some parents remain mistrustful. The U.S. Centers for Disease Control and Prevention has launched a series of studies into the potential causes of autism.
In a second study, a team at Cornell University and Indiana University-Purdue University found that television viewing may be a factor among American children.
Michael Waldman of Cornell University and colleagues found that children from rainy U.S. counties watch more television and autism rates corresponded with this pattern.
"The analysis shows that early childhood television viewing could be an environmental trigger for the onset of autism and strongly points to the need for more research by experts in the field of autism," said Waldman, who will present his findings on Friday to a conference of the National Bureau of Economic Research.
A third team of researchers found that the brain regions of adults with autism may not communicate with each other as efficiently as they do in other people.
Michael Murias and colleagues at the University of Washington used high-resolution electroencephalography or EEG to find patterns of abnormal connectivity between brain regions in 36 people with autism.
http://today.reuters.com/news/articlenews.aspx?type=healthNews&storyID=2006-10-16T220545Z_01_N16413740_RTRUKOC_0_US-AUTISM.xml&pageNumber=0&imageid=&cap=&sz=14&WTModLoc=NewsArt-C1-ArticlePage3 认领了 交稿，译文
美国研究发现增加罹患孤独症的突变基因
2006，10，16，下午6：05，星期一，
Maggie Fox 健康科学主编
华盛顿（路透通讯社）--美国研究者在周一表示他们鉴定了一个能够增加罹患孤独症的突变基因，并且这个突变同时可以解释一些孤独症儿童的其它症状。
虽然孤独症与相似的障碍有家族聚集现象，但是他们的研究是第一个找到与这种障碍有确定联系的研究。在美国儿童中1/175的人遭受这种障碍的折磨。
范德比尔大学的Pat Levitt博士及其同事（田纳西州纳什维尔市）对743个家族进行了研究，在这 743个家族中有1200名家族成员罹患过孤独症谱群疾病，病情由完全自闭到亚斯伯格症候群各不相同。
他们发现了名为MET的基因中的单突变，而已知MET基因与大脑发育、免疫系统调节、胃肠系统修复有关。患有孤独症的儿童其所有这些系统都会受累。
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作者:admin@医学,生命科学 2011-03-25 17:42
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