Health Watch -- Causes of Heart Defects

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Researchers may have found a cause for one type of congenital heart defect.

Congenital heart defects - when a baby is born with structural defects to the heart - are the leading cause of non-infectious newborn deaths. But doctors have known little about what causes these defects. Only one gene had been identified as a cause of heart defects not associated with any other known medical syndromes.

But now researchers at UT Southwestern Medical Center at Dallas have found another gene that appears to cause congenital heart defects. Researchers hope that by identifying this gene, they will then be able to come up with treatments to prevent heart defects.

The Texas researchers and their colleagues in Japan studied large families that had a frequent occurrence of congenital heart defects. By comparing the genetic codes of family members who had defects to those of family members who did not, researchers were able to narrow in on the gene that made the difference.

The gene called GATA4 was mutated in all the family members with heart defects but not in the family members without the condition, nor in thousands of unrelated people without heart defects. This gene appears to interact with a protein to divide the heart into its four chambers as it develops. When the gene is mutated, the walls between the heart chambers don't form properly.

Now researchers plan to see how common this genetic mutation is among people with heart defects - and one day find a way to treat or prevent the condition altogether.