Are Atrial Septal Defects and PFOs Hereditary?

It is completely normal to worry about the health of your other children after one receives a congenital heart diagnosis. If your child has been diagnosed with an atrial septal defect (ASD) or a patent foramen ovale (PFO), you may wonder if their siblings need to be checked. The short answer is that most ASDs and PFOs happen by chance, but there is a slightly higher risk for siblings to have a heart defect. Whether siblings need screening depends on the specific diagnosis and your family history.

The Genetics of Atrial Septal Defects (ASDs)

An atrial septal defect (ASD) is a structural hole in the wall between the heart’s upper chambers. Most of the time, an isolated ASD happens sporadically, meaning it occurs by chance without a clear single genetic cause ^[1].

However, congenital heart defects do have a small hereditary component. For siblings of a child with an isolated ASD, the risk of also having a congenital heart defect is generally estimated to be between 2% and 4% ^[2]. This is slightly higher than the general population risk (which is less than 1%), but the vast majority of siblings will have a perfectly healthy heart ^[2][1].

In a smaller number of cases, an ASD can be strongly linked to genetics. If an ASD is associated with specific gene mutations, it is often inherited alongside other issues, like heart block (an electrical issue that causes a slow or irregular heartbeat) ^[3][1]. The recurrence risk in these families is much higher. You do not need to guess if your child has this—your child’s cardiologist would typically spot heart block on a routine EKG and discuss genetic testing with you.

Are Patent Foramen Ovales (PFOs) Hereditary?

A patent foramen ovale (PFO) is completely different from an ASD. A PFO is a small flap-like opening that is a normal part of fetal circulation. It usually seals shut after birth, but in about 25% of the general population, it remains slightly open ^[4].

Because PFOs are so common and are considered a normal anatomical variation rather than a structural defect, they do not carry the same hereditary concerns as an ASD ^[4]. Routine screening for a PFO in healthy, asymptomatic family members is not recommended ^[5].

Should My Other Children Be Checked?

There is no universal medical rule that mandates an echocardiogram (a painless ultrasound of the heart) for every sibling of a child with an ASD ^[1][2]. Generally, an echocardiogram is only recommended if a physical exam uncovers a concern or if your family meets specific high-risk criteria.

Your child’s care team is most likely to recommend checking siblings with an echocardiogram if:

• You have a strong family history of congenital heart defects, unexplained sudden cardiac death, or early heart surgeries ^[2].
• The child with the ASD also has an abnormal heart rhythm ^[3].
• A sibling shows symptoms such as unusual fatigue during play, shortness of breath, or poor growth.
• The ASD is part of a known genetic syndrome, such as Down syndrome or Holt-Oram syndrome (a rare genetic condition affecting the heart and the bones of the hands or arms) ^[1].

A simple physical exam by a pediatrician, where they listen carefully for a heart murmur, is a great starting point. However, because ASD murmurs can sometimes be subtle or hard to hear, paying attention to physical symptoms is also important. If there is any concern, the doctor can refer your child for an electrocardiogram (EKG) (a quick, non-invasive test measuring the heart’s electrical activity) or an echocardiogram to be absolutely sure.