Is Brugada Syndrome hereditary?

TL;DR: Brugada Syndrome is a genetic condition that is primarily inherited in an autosomal dominant pattern, meaning an affected individual has a 50% chance of passing the genetic variant to each child. While it is hereditary, Brugada Syndrome can also arise from de novo (spontaneous) mutations, and the clinical expression of the disease varies significantly even among family members with the same genetic variant.

Is Brugada Syndrome hereditary?

Yes, Brugada Syndrome is considered a hereditary heart rhythm disorder. It is primarily caused by mutations in genes that encode for cardiac ion channels, most notably the SCN5A gene. Because it follows an autosomal dominant inheritance pattern, a single copy of the altered gene from one parent is sufficient to cause the condition. However, it is important to note that carrying the genetic variant does not guarantee that an individual will develop the clinical symptoms of Brugada Syndrome. This phenomenon, known as incomplete penetrance, means some individuals may carry the gene but never exhibit the characteristic electrocardiogram (ECG) patterns or experience symptoms.

What is the role of genetic testing in Brugada Syndrome?

Genetic testing is a valuable tool for families affected by Brugada Syndrome, though it is not used as a standalone diagnostic tool. The diagnosis of Brugada Syndrome is primarily clinical, based on specific ECG findings (Type 1 Brugada pattern) and the patient's medical history. Genetic testing is currently recommended in the following scenarios:

• To confirm a diagnosis in individuals who present with a suspected Brugada Syndrome ECG pattern.


• To facilitate cascade screening for at-risk family members.


• To provide reproductive planning options for parents who know they carry a pathogenic variant.

It is important to understand that in approximately 70-80% of clinically diagnosed cases, a causative genetic mutation cannot be identified with current technology. Therefore, a negative genetic test does not rule out the presence of Brugada Syndrome.

Are de novo mutations common in Brugada Syndrome?

While most cases of Brugada Syndrome are inherited from a parent, de novo mutations—new mutations that occur for the first time in an individual—do occur. When a person is identified with a pathogenic variant but neither parent carries it, this suggests a spontaneous mutation. Because the clinical presentation of Brugada Syndrome is so variable, it is also possible that a parent may carry the mutation but remain asymptomatic and undiagnosed, making the condition appear de novo when it is actually familial.

Why is genetic counseling important for Brugada Syndrome families?

Given the complexity of Brugada Syndrome, genetic counseling is strongly recommended for all affected families. A genetic counselor can help interpret test results, calculate recurrence risks, and discuss the implications of the diagnosis for relatives. For those planning pregnancies, genetic counseling provides a space to discuss options such as preimplantation genetic testing (PGT) or prenatal diagnosis. Within the DiseaseMaps.org community, our 228 members often emphasize that understanding the genetic basis of Brugada Syndrome helps reduce the anxiety surrounding sudden cardiac risk by empowering families to undergo appropriate cardiovascular surveillance.

Next steps

• Consult a cardiac electrophysiologist to determine if clinical screening is appropriate for your family members.


• Request a referral to a clinical geneticist or genetic counselor to discuss the benefits and limitations of SCN5A and other panel testing.


• Join the DiseaseMaps.org community to connect with others navigating the hereditary aspects of Brugada Syndrome.


• Maintain a detailed family health history, noting any instances of unexplained fainting or sudden cardiac death in relatives.

Medical disclaimer: This information is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Brugada Syndrome


• Orphanet: Brugada Syndrome (ORPHA:132)


• OMIM (Online Mendelian Inheritance in Man): Brugada Syndrome 1 (Entry #601144)


• Heart Rhythm Society (HRS) Expert Consensus Statements on Inherited Primary Arrhythmia Syndromes