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Genetic and Rare Diseases Information Center (GARD)

Hypoplastic left heart syndrome

Other Names for this Disease
  • HLHS
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

Years ago I lost an infant to HLHS. I have another child who is now an adult. Should he be genetically tested and counseled before having children?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

When should a person seek preconception genetic counseling for congenital heart disease?

The best time to learn about genetic risks and testing options is before pregnancy. Assessing risks in families affected by congenital heart disease (CHD) is a complex process that takes into account the affected family member's heart defect, medical history, physical and other characteristics, as well as the family medical history.  In general, people who may benefit from preconception genetic counseling for CHD include:[1]

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.

Last updated: 4/17/2013

Is hypoplastic left heart syndrome genetic?

In most cases, hypoplastic left heart syndrome (HLHS) occurs in an individual who has no family history of the condition. Little is known regarding how specific genes affect HLHS risk. Populations studies have estimated that the risk to first degree relatives of individuals with HLHS is 2 to 4 percent.[2][3] In other words if you have HLHS and no family history or chromosomal abnormality, you are estimated to have a 2% to 4% chance of passing HLHS to your offspring. This risk decreases as you go from first-degree to second-degree relatives. 

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.[2]

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.[3] 

Last updated: 4/17/2013

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:
Last updated: 5/18/2016

  • Burchill L, Greenway S, Silversides CK, Mital S. Genetic counseling in the adult with congenital heart disease: what is the role?. Curr Cardiol Rep. 2011 Aug;13(4):347-55; Accessed 4/17/2013.
  • Hypoplastic left heart syndrome. OMIM. January 2012; Accessed 4/17/2013.
  • Marshall A. Hypoplastic left heart syndrome. In: Basow, DS (Ed). UpToDate. Waltham, MA: UpToDate; 2013;
Other Names for this Disease
  • HLHS
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.