A gene which may hold the key to some inherited heart defects has been discovered by US scientists.
Many heart defects can be corrected
Aside from infections, heart defects are the most common cause of death in newborn babies.
Although surgeons can now operate to correct many different types, often just a few days after birth, such operations carry a high degree of risk to the baby.
The researchers, from the University of Texas Southwestern Medical Center in Dallas, believe they have found a gene which plays a key role in the development of the foetal heart.
It has been linked to "septal" defects, in which the wall which separates the four chambers of the heart fails to develop properly.
This is one of the genes responsible, and we are working to identify others
Dr Vidu Garg, University of Texas
This can lead to many variations on the classic "hole-in-the-heart" which prevents efficient pumping of the blood around the body.
If the foetus has a mutation in this gene, it is much more likely that the heart will not develop properly.
Dr Vidu Garg, assistant professor of paediatric at Southwestern, said: "In terms of the genetic origins, there are not many discoveries that have been made.
"This is one of the genes responsible, and we are working to identify others.
"We cannot change the fact that parents are gong to pass along the mutation, but we might be able to develop a way to keep the disease from occurring."
The study looked at two large families with a strong history of congenital heart disease, one from Dallas itself, and another from Tokyo.
In all, dozens of family members from many generations underwent genetic screening.
Mutations of the gene, called GATA4, were found in all family members who had been born with congenital heart defects, but not those who were free of defects - or more than 3,000 other unrelated people.
The next step for researchers is to find out how common such mutations are in the general population of children.
If GATA4 does emerge as a key genetic player in the defective development of the heart, then it may be possible to help families with a strong history of such problems.
It is already possible to screen IVF embryos to rule out those with a few gene-linked conditions.