Brugada syndrome

The genetic form of Brugada syndrome (not the acquired form) is inherited in an autosomal dominant manner. This means that having one mutated copy of the responsible gene in each cell is enough to cause signs or symptoms. Almost all people with Brugada syndrome have a parent with the condition. In about 1% of cases, an affected person has a new mutation in the responsible gene and has no family history of the condition. Each child of an affected person has a 50% chance to inherit the mutated gene.^[1]

Unsymptomatic parents of an affected person should be evaluated with electrocardiography, and any family history of sudden death should be discussed. If genetic testing reveals a mutation in the affected person, genetic testing of the parents is recommended. A family history may appear to be negative due to reduced penetrance, death of a parent before symptoms start, or late onset of symptoms in an affected parent.^[1]

In almost all cases, a person with Brugada syndrome inherits the condition from a parent who has a mutated copy of one of the genes responsible for the condition. In about 1% of cases, the condition results from a new (de novo) mutation that occurs for the first time in the affected individual.^[1]

Mutations that cause Brugada syndrome have been found in 16 different genes. However, only about 25% to 30% of cases are caused by a mutation in one of these genes (usually the SCN5A gene). This means that there are likely mutations in other, unidentified genes that cause Brugada syndrome.^[1] This also means that 70-75% of affected people will not test positive for a mutation when they have genetic testing.

If a genetic mutation is found in an affected family member, genetic testing of both parents and other at-risk relatives is appropriate.^[1] Genetic testing only in the affected person does not show where the mutation came from.

If a mutation in an affected person is not found, relatives should be screened with an ECG, and further testing may be needed in some cases.^[1] Attention to a family history of sudden death can be important in determining who may be at risk for the condition.^[1]

People interested in learning more about the inheritance of Brugada syndrome and genetic testing should speak with a genetics professional.

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.