They found that all five generations of the family including children and adults, had a mutation on a gene called NOTCH1.
Dr Vidu Garg, an assistant professor of pediatrics and molecular biology, says that mutations in NOTCH1 cause an early developmental defect in the aortic valve.
The researchers finding was confirmed, when they found a second mutation on the same gene in members of a smaller family in San Diego.
Normally the aortic valve is composed of three flaps of tissue that open and close to enable blood to flow in one direction, but a very small percent of the population are born with valves with only two flaps which make them susceptible to aortic valve stenosis.
This condition, which narrows the passage through which blood exits the heart, can require surgery at birth.
In severe cases the heart does not develop properly in the fetus and the child is born with an illness called hypoplastic left heart syndrome, which is a leading cause of heart disease deaths in children.
Dr Deepak Srivastava, of the University of California, San Francisco, who contributed to the research, says they know that aortic valve problems causes those deaths, but they now think NOTCH1 mutations are also likely to be the cause of some cases of hypoplastic left heart syndrome.
According to the scientists the finding could help to identify people at risk of the problem, and when researchers have a better understanding of the full impact of the mutation it could pave the way for new treatments for the heart ailments.
The finding is reported in the science journal Nature.
swmed/The condition currently exacts a huge financial burden on the system, with surviving babies often being treated in neo-natal intensive care units for lengthy periods as well as any future complications that may arise in adulthood. It obviously also takes a heavy emotional toll on the mother. This latest discovery will likely lessen both.
"This is an exciting discovery that holds great clinical potential," noted Dr. Nathalie Fleming, an OB/GYN and Assistant Professor at the University of Ottawa. "It is often difficult to identify the reason for these growth restricted fetuses. Having discovered a marker like this may help us diagnose the cause of these small fetuses and allow us to monitor these high risk pregnancies more carefully."
"I am delighted that we are able to collaborate in this exciting project where basic science research helps to unravel the mysteries of human reproductive diseases. With the human genome sequenced, treatment of human diseases in the future may be revolutionized and tailored to the patient's genetic makeup," said Dr. Ben Tsang, Senior Scientist at the Ottawa Health Research Institute and Professor of Obstetrics & Gynaecology at the University of Ottawa.
The research was funded thanks to a grant from the Canadian Institutes of Health Research.
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