Genetic mutations in the womb could be contributor to autism
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New studies appearing today in the journal Nature featuring analysis from researchers at Pittsburgh universities shows that genetic mutations in the womb may account for about 15 percent of all cases of autism.
The studies were carried out at Harvard and Yale universities and the University of Washington. They examined the protein-coding portions of the genomes of 549 families in which there was one child with autism but parents and siblings did not have the disorder.
In two of the studies, Kathryn Roeder of Carnegie Mellon University and Bernie Devlin of the University of Pittsburgh provided key analysis of the genes.
Researchers believe that in many cases of autism, children inherit genes from the parents. But in this study, the scientists zeroed in on mutations that occur spontaneously in the womb.
They found that there were scores of genes in the autistic children that showed these mutations, but they appeared to cluster in three genes known as SCN2A, CHD8 and KATNAL2.
Stephan Sanders, a lead researcher in the Yale study, said SCN2A has been implicated in epilepsy. The other two genes help govern the basic architecture and connectivity of brain cells, he said.
While it's too early to tell exactly how the genes identified today might contribute to autism, Dr. Sanders said the technique used to find them holds out hope of locating many more autism genes. His study group worked with 238 families, and hopes by the end of this year to scan the genomes of more than 2,000 families.
One of the studies published today also notes that the fetal mutations are four times more likely to come from the father's germline than the mother's, and that the older the dads were, the more mutations occurred.
"That's interesting from a science point of view," Dr. Sanders said, "but not from a who-should-get-married point of view."
Autism is a brain disorder that affects social communication skills and often involves obsessive interests or repetitive behaviors. The latest federal figures estimate that 1 in 88 children in America are on the autism spectrum.
As the genome sequencing continues, Dr. Sanders said, "I think by the end of this year we'll have found enough genes to find which pathways are involved in the autism processes, and then we might be able to see when and where in the brain this is taking place, and further down the road -- possibly in five years or more -- we will be able to start devising treatments based on that information."
First Published April 4, 2012 1:14 pm