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PubMed This is a summary of 10 peer-reviewed journal articles Updated
Cardiology

The Biology and Genetics of Brugada Syndrome

At a Glance

Brugada syndrome is a genetic heart rhythm disorder primarily caused by a mutation in the SCN5A gene, which affects the heart's sodium channels. It has a 50% chance of being passed to children, making genetic counseling and family screening essential.

Brugada syndrome is often called a “hidden” condition because it doesn’t change the way your heart looks—it only changes the way it “talks” electrically. To understand why this happens, we have to look at the microscopic “gates” that control the electricity in your heart cells [1].

The Biological Mechanism: Sodium Channels

Your heart beats because of a carefully timed flow of electricity. This electricity is created by ion channels, which are tiny gates on the surface of your heart cells that let minerals like sodium, potassium, and calcium flow in and out [2].

In Brugada syndrome, there is a loss of function in the sodium channels (specifically one called Nav1.5) [3][4]. Because these gates don’t open or close correctly, the sodium current is too weak. This disruption happens primarily during repolarization—the phase where the heart’s electrical system “resets” itself for the next beat [2][1]. This “resetting” error can create an electrical imbalance that leads to dangerous heart rhythms.

The Role of the SCN5A Gene

The most well-known “instruction manual” for building these sodium gates is a gene called SCN5A [5][3].

  • Prevalence: Up to 30% of people diagnosed with Brugada syndrome have a mutation in the SCN5A gene [5][1].
  • Other Genes: While SCN5A is the most common, researchers have found other genes (such as SCN10A, PKP2, and XIRP2) that may play a role in familial Brugada syndrome [6][7].
  • Negative Results: It is important to know that many patients with Brugada syndrome have a “negative” genetic test. This doesn’t mean you don’t have the condition; it just means science hasn’t identified your specific genetic “instruction” error yet [1].

How It Is Inherited

Brugada syndrome typically follows an autosomal dominant pattern of inheritance. This means:

  1. 50/50 Chance: If you have the condition, there is a 50% chance of passing the genetic trait to each of your children [3].
  2. Incomplete Penetrance: Not everyone who inherits the gene will actually develop the syndrome or have symptoms. You might have the gene but a perfectly normal ECG, while your sibling might have the same gene and show the Brugada pattern [1].
  3. Family Screening: Because of this, it is recommended that all first-degree relatives (parents, siblings, and children) be screened by a cardiologist, even if they feel perfectly healthy [8].

Consulting a Genetic Counselor

Navigating genetic testing, incomplete penetrance, and family screening can be highly emotional and complex. It is highly recommended to consult a Genetic Counselor. They are specifically trained to help you understand your test results, map out your family tree, and guide you on the best way to approach your relatives about getting screened [9].

Molecular Autopsies: Finding Answers

Sometimes, Brugada syndrome is only suspected after a tragic, unexplained death in a family (often called SADS, or Sudden Arrhythmic Death Syndrome). In these cases, doctors can perform a postmortem genetic test or molecular autopsy [8][10]. This is a specialized genetic test on tissue from the deceased person to look for mutations like SCN5A [9].

Finding a cause through a molecular autopsy is incredibly valuable for the survivors. It allows doctors to test living family members for that specific mutation, identifying those at risk before an event happens and providing peace of mind for those who did not inherit the trait [8][9].

Common questions in this guide

Is Brugada syndrome hereditary?
Yes, Brugada syndrome typically follows an autosomal dominant inheritance pattern. This means if you have the condition, there is a 50% chance of passing the genetic trait to each of your children.
What does a negative genetic test mean for Brugada syndrome?
A negative genetic test does not mean you do not have Brugada syndrome. It simply means that your specific genetic mutation has not yet been identified, as only about 30% of cases are linked to the most common gene, SCN5A.
Who in my family should be screened for Brugada syndrome?
All first-degree relatives, which includes your parents, siblings, and children, should be screened by a cardiologist. This is crucial because a person can carry the genetic mutation without showing any symptoms.
What is incomplete penetrance in Brugada syndrome?
Incomplete penetrance means that not everyone who inherits a Brugada syndrome gene mutation will develop symptoms or have an abnormal ECG. You can carry the gene while remaining completely healthy, while a relative with the same gene might show signs of the condition.
What is a molecular autopsy?
A molecular autopsy is a specialized genetic test performed on tissue after an unexplained sudden death. Identifying a genetic cause like an SCN5A mutation helps doctors test and protect surviving family members who might be at risk.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my ECG and history, do you recommend I undergo genetic testing for the SCN5A gene?
  2. 2.If my genetic test comes back 'negative,' does that mean I don't have Brugada syndrome, or are there other genes we should look at?
  3. 3.Which of my family members (children, siblings, parents) should be screened, and what specific tests do they need?
  4. 4.If a genetic mutation is found, does that change my risk level or the way we manage my triggers?
  5. 5.Can you explain 'incomplete penetrance' and what it means for my children's risk of developing symptoms?

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Is Brugada Syndrome Hereditary? | Inciteful MedWhat Is a Molecular Autopsy for Brugada Syndrome?

References

References (10)
  1. 1

    Triggers for arrhythmogenesis in the Brugada and long QT 3 syndromes.

    Peters CH, Abdelsayed M, Ruben PC

    Progress in biophysics and molecular biology 2016; (120(1-3)):77-88.

    PMID: 26713557
  2. 2

    Brugada Syndrome: From Molecular Mechanisms and Genetics to Risk Stratification.

    Popa IP, Șerban DN, Mărănducă MA, et al.

    International journal of molecular sciences 2023; (24(4)) doi:10.3390/ijms24043328.

    PMID: 36834739
  3. 3

    Dominant negative effects of SCN5A missense variants.

    O'Neill MJ, Muhammad A, Li B, et al.

    Genetics in medicine : official journal of the American College of Medical Genetics 2022; (24(6)):1238-1248 doi:10.1016/j.gim.2022.02.010.

    PMID: 35305865
  4. 4

    Identification of a novel missense SCN5A mutation in a Chinese Han family with Brugada syndrome.

    Zhu J, Shen Y, Xiong H, et al.

    Biochemical and biophysical research communications 2023; (649()):55-61 doi:10.1016/j.bbrc.2023.01.026.

    PMID: 36745970
  5. 5

    SCN5A Variants: Association With Cardiac Disorders.

    Li W, Yin L, Shen C, et al.

    Frontiers in physiology 2018; (9()):1372 doi:10.3389/fphys.2018.01372.

    PMID: 30364184
  6. 6

    Molecular Autopsy of Desmosomal Protein Plakophilin-2 in Sudden Unexplained Nocturnal Death Syndrome.

    Huang L, Tang S, Peng L, et al.

    Journal of forensic sciences 2016; (61(3)):687-91 doi:10.1111/1556-4029.13027.

    PMID: 27122407
  7. 7

    Critical Roles of Xirp Proteins in Cardiac Conduction and Their Rare Variants Identified in Sudden Unexplained Nocturnal Death Syndrome and Brugada Syndrome in Chinese Han Population.

    Huang L, Wu KH, Zhang L, et al.

    Journal of the American Heart Association 2018; (7(1)) doi:10.1161/JAHA.117.006320.

    PMID: 29306897
  8. 8

    Molecular autopsy in victims of inherited arrhythmias.

    Semsarian C, Ingles J

    Journal of arrhythmia 2016; (32(5)):359-365 doi:10.1016/j.joa.2015.09.010.

    PMID: 27761159
  9. 9

    Forensic pathological and genetic landmarks in sudden cardiac death in the young: An update.

    Grassi S, Campuzano O, Ferri E, et al.

    Forensic science international. Genetics 2026; (80()):103334 doi:10.1016/j.fsigen.2025.103334.

    PMID: 40753706
  10. 10

    The role of genetic testing in unexplained sudden death.

    Miles CJ, Behr ER

    Translational research : the journal of laboratory and clinical medicine 2016; (168()):59-73 doi:10.1016/j.trsl.2015.06.007.

    PMID: 26143861

This page explains the genetics and biology of Brugada syndrome for educational purposes only. Always consult a genetic counselor or cardiologist regarding genetic testing, inheritance, and family screening.

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