ARTICLES

Researchers find many genes related to autism


Unlike
children with cystic fibrosis, whose disease is caused by defects in a
single gene, people with autism may share little in common genetically,
says study co-author Stephen Scherer, who compared the DNA of nearly
1,000 children with autism with nearly 1,300 children who don’t have
autism.

By LIZ SZABO
USA TODAY

Published: Thursday, June 10, 2010 at 10:55 a.m.
Last Modified: Thursday, June 10, 2010 at 10:55 a.m.

( page 2 of 2 )

Scientists have found dozens of new autism-related genes, according
to a study that eventually could help doctors develop better ways to
diagnose and treat the condition.

Yet the study, published online Wednesday in Nature, also suggests that the genetic roots of autism are quite complicated.

Unlike
children with cystic fibrosis, whose disease is caused by defects in a
single gene, people with autism may share little in common genetically,
says study co-author Stephen Scherer, who compared the DNA of nearly
1,000 children with autism with nearly 1,300 children who don’t have
autism.

But even the most
common genetic changes in his study were found in only 1 percent or
less of patients, Scherer says. That suggests that “most individuals
with autism are probably genetically quite unique,” says Scherer of the
Hospital for Sick Children in Toronto, one of 120 scientists from 11
countries working on the study, called the Autism Genome Project.

As
co-author Stanley Nelson of the University of California-Los Angeles
describes it: “If you had 100 kids with autism, you could have 100
different genetic causes.”

Taken
together, these genetic changes could explain up to 20 percent of cases
of autism, says Hakon Hakonarson, director of Children’s Hospital of
Philadelphia’s Center for Applied Genomics, a co-author of the study,
which was funded by Autism Speaks and the National Institutes of Health.

Researchers
focused on a type of genetic change called “copy number variations,”
places where DNA has been either inserted or deleted. Because genes
include instructions for making proteins, that can lead to an overdose
of a protein, an underdose, a total absence of protein or a
malfunctioning one, Hakonarson says.

But
much about autism remains a mystery, including the cause of the other
80 percent of cases, says Bryan King, an autism expert at Seattle
Children’s Hospital. Study authors say they need to study the genes of
many more children to get more precise answers about autism’s genetic
roots.

But doctors may
one day be able to use these findings to offer parents an early genetic
test to help predict children’s risk of autism, says co-author Louise
Gallagher of Trinity College Dublin.

The
study also could lead to new drugs, because it points out new genetic
targets, says co-author Anthony Monaco of the Wellcome Trust Centre for
Human Genetics in the United Kingdom.

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