This new insight is based on new research and the outcome is troubling in that the causes of congenital heart defects are far more complex than previously thought. University of California – Irvine researchers have uncovered how the major risk factors for heart defects relate to areas of the body outside of the heart itself.
A congenital heart defect is a problem in the structure of the heart that is present at birth. The signs and symptoms vary and the outcomes can be mild to life-threatening. In some people the defects lead to rapid breathing, bluish skin, poor weight gain, and feeling tired.
Due to the commonality and seriousness of the condition, considerable research goes into studying congenital heart defects. The new finding has come from looking at a specific type of defect called atrial septal defects (which leads to abnormalities of the bones in the arms, hands, and fingers); the experimental findings relate to the use of a mouse model.
The experiments led to a focus on a gene called Nipbl. In both people and mice, atrial septal defects are linked to mutations that inactivate a single copy of Nipbl. Interestingly, this mutation can occur anywhere within the body (not just the heart.) The loss of activity from just one Nipbl copy triggers a chain reaction of damage.
The study on mice found when mice have the mutation there is a 30 percent chance of the mice developing atrial septal defects. This was found through experimenting with introducing or eliminating Nipbl mutations in different tissues within the test mice. This showed that heart defect development was controlled by intricate interactions between gene activity in tissues of the heart and tissues from all over the body.
Discussing the serious nature of the results with Laboratory Roots, lead researcher Professor Anne Calof said: “Our results lead us to hypothesize that heart defects such as [atrial septal defects] occur when the heart does not grow quickly enough to meet the demands of the developing body.”
The findings are published in the journal PLOS Biology. The paper is titled “The Hole and the Whole: Lessons from Manipulation of Nipbl Deficiency.”
