When parents first discover that their baby or child has a heart abnormality, it is common to ask, "Why has this happened?" and "How can I stop this from happening again?"
In many cases, it's difficult to give an exact reason why this has happened. The main structural development of the heart is finished by about 12 weeks after conception, although changes do still occur after that time. While we can't be sure in every case, genetics probably accounts (to varying degrees) for many of the cases of congenital heart disease.
Genetics can make a heart abnormality possible but for this to appear as an abnormality other "triggers" may be needed. These triggers may happen simply through bad luck. There are some heart abnormalities where we can identify an increase or decrease in the number of chromosomes, or a change in a gene locus (a small section of a chromosome with some important information) to explain why this occurs.
In some cases, although we don't know the exact gene locus yet, we know of other abnormalities or certain physical characteristics that occur together at higher frequency than by chance. Such a collection of characteristics is called a Syndrome. With ongoing research we learn more about the genes associated with these Syndromes.
If we know the chromosomal or gene change, it can be easier to predict how likely it is that an abnormality might occur in a brother, sister, offspring or parent of the affected child. If there are no other family members with congenital structural abnormalities of the heart, the chance of a congenital heart abnormality in a future pregnancy (brother or sister) is quite small: about 3-4%. This is compared with the usual community risk of about 1%. It's important not to be confused about other family members who seem to have a "heart abnormality". There are many different abnormalities of the heart, and in general, "adult - type" heart problems (such as heart attacks, blood pressure or high cholesterol) are not related to congenital structural heart abnormalities. Also, remember that having a "murmur" may be completely normal, and not connected with any abnormality.
Our knowledge is increasing all the time. At the Heart Centre for Children we are engaged in very specific research to explore the genetic causes of heart disease in children. If you're worried about any aspect of your child's health, or want to understand more about what might have caused his or her heart abnormality, it is important that you talk to your child's doctors. If you want to know more, you can ask your cardiologist or surgeon, or we can help direct you to a geneticist to discuss this further.
Disclaimer: This information is intended as a general guide only and not to provide specific information for individual patient care. Any questions about your own situation should be directed to your medical practitioner, or cardiac specialist, or you can contact us and ask to speak to a Clinical Nurse Consultant.