From Science Daily:
Study Finds Regions Of DNA That Appear Linked To Autistic Spectrum Disorders
May 10, 2007
Science Daily — Using an innovative statistical approach, a research team from Washington University School of Medicine in St. Louis and the University of California, Los Angeles, has identified two regions of DNA linked to autism. They found the suspicious DNA with a much smaller sample of people than has been used traditionally in searches for autism genes.
Autism -- a disorder that involves social deficits, language problems and repetitive, stereotyped behaviors -- affects around one in 1,000 children. And the combined incidence of autism spectrum disorders, which include Asperger syndrome and pervasive developmental disorder, brings the total number of affected children to one in every 150 births. Boys are affected three to four times more often than girls.
There's clearly a genetic component to autism, according to John N. Constantino, M.D., associate professor of psychiatry and pediatrics at Washington University School of Medicine and a co-principal investigator on this latest study. If one child in a family is autistic, there's a 10 percent chance a sibling also will have autism. Past research has isolated a few regions of DNA linked to autism, but very few of those studies have been replicated, so no specific autism genes have yet been identified.
"Those older studies used what's called an 'affected sib pair' design that looks for genetic markers in siblings with autism," says Constantino. "That approach has worked well for single-gene disorders, but autism is a complex disease that may involve many genes that each make very small contributions. When that's the case, it's harder to find genetic markers."
So Constantino's group, in collaboration with the other co-principal investigator, Daniel H. Geschwind, M.D., Ph.D., and neuropsychiatric and genetics researchers at UCLA, is using a different approach. They report their findings in the April issue of the American Journal of Psychiatry.
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