Infants' heart defects tied to new mutations

About 10 percent of congenital heart defects may come from spontaneous, rather than inherited, gene mutations, according to a study that offers new insight into a condition that can range from simple to severe.

Scientists investigated the DNA of 362 newborns with serious defects in families where neither the parents nor the child's siblings had a history of cardiac problems.

The research, reported online this week in the journal Nature, found hundreds of mutations that existed only in the affected children.

Congenital heart defects occur in 8 out of every 1,000 newborns in the United States, or more than 35,000 children yearly, according to the National Heart, Lung and Blood Institute. While the findings may not help prevent the condition, identifying the variants may one day aid doctors in individualizing treatments, the researchers said.

Understanding the role of the variants may help improve outcomes, said co-author Christine Seidman, director of the Cardiovascular Genetics Center at Brigham and Women's Hospital in Boston. "After we repair the hearts of these children, some children do great and some do poorly," said Seidman, a researcher at the Howard Hughes Medical Institute in Chevy Chase, Md. Scientists have long suspected this might be due to differences in the underlying causes of the disease, she said.

Researchers compared DNA from children with heart defects and healthy babies. Both had about the same number of so-called de novo mutations, the noninherited variants. The sick children, though, were much more likely to have a damaging mutation in genes expressed in the developing heart.

The research was undertaken by the Pediatric Cardiac Genomics Consortium, and involved scientists at nine U.S. centers and one in Britain.

-- Bloomberg News