Brugada Syndrome

What is Brugada syndrome?

Brugada syndrome is a condition that causes a disruption of the heart's normal rhythm. Specifically, this disorder can lead to uncoordinated electrical activity in the heart's lower chambers (ventricles), an abnormality called ventricular arrhythmia. If untreated, the irregular heartbeats can cause fainting (syncope), seizures, difficulty breathing, or sudden death.

Sudden unexplained nocturnal death syndrome (SUNDS) is a condition characterised by unexpected cardiac arrest in young adults, usually during sleep. This condition was originally described in Southeast Asian populations, where it is a major cause of death. Researchers have determined that SUNDS and Brugada syndrome are the same disorder.

How common is Brugada syndrome?

The incidence of Brugada syndrome is not known, but the disorder has been described in populations worldwide. It occurs more frequently in people of Asian ancestry, particularly in Japanese and Southeast Asian populations.

Although Brugada syndrome affects both men and women, the condition appears to be more common in men.

What genes are related to Brugada syndrome?

Mutations in the SCN5A gene cause Brugada syndrome.

Mutations in the SCN5A gene have been identified in about 20 percent of people with Brugada syndrome. The protein made by this gene forms a channel that normally transports positively charged sodium atoms (ions) into heart muscle cells. These ion channels play a critical role in maintaining the heart's normal rhythm. Mutations in the SCN5A gene alter the structure or function of the channels, which reduces the flow of sodium ions into cells. A disruption in ion transport alters the way the heart beats, leading to the abnormal heart rhythm characteristic of Brugada syndrome.

In affected people without an identified SCN5A mutation, the cause of the condition is unknown.

How do people inherit Brugada syndrome?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.

What other names do people use for Brugada syndrome?

• Sudden unexpected nocturnal death syndrome
• Sudden unexplained death syndrome
• SUDS
• SUNDS