The following information may help to address your question:
Adults who have CHD, to learn more about risks to their children
Parents of a child with CHD, to learn more about risk to siblings
People with a strong family history of CHD
People with signs and symptoms of a genetic syndrome associated with CHD, such as distinct facial characteristics, birth defects, learning impairment, behavioral and/or psychiatric disorders
People with types of CHD known to occur in association with a genetic condition, such as 22q11.2 deletion
When genetic testing is available, testing typically begins with the family member who has CHD when possible. Testing on this individual has the greatest likelihood of finding a genetic cause for CHD. Currently clinical genetic testing is available for only select causes of CHD. Most cases of isolated CHD are thought to be sporadic and informative genetic tests are not readily available. If you are unsure if your son would benefit from genetic counseling, we encourage him to speak with his healthcare provider.
In addition, you may find the following article to be a helpful resource. The article provides a comprehensive overview of healthcare decisions and testing considerations couples can make to help ensure a healthy pregnancy.
Brundage SC. Preconception Health Care. American Family Physician. 2002 Jun 15;65(12):2507-2515.
When a spectrum of left heart anomalies, called left ventricular outflow tract obstruction (LVOTO), are considered together, recurrence risk has been estimated to be higher. LVOTO spectrum disorders span from severe to minor heart anomalies and include, hypoplastic left heart, aortic valve stenosis, bicuspid aortic valve, hypoplastic aortic arch, and coarctation of the aorta. For LVOTO, recurrence risk in first degree relatives is estimated to be close to 40%. Severity of the LVOTO anomalies vary widely within families, from severe (HLH) to very mild.
Lastly, there have been rare reports of famililies with multiple members with HLHS, not fitting with a 2% to 4% recurrence risk. The cause of HLHS in these families is not known. In addition, HLH has been described in people with the chromosome conditions Turner syndrome, Jacobsen syndrome, trisomy 13, and trisomy 18.