Who's affected

Brugada syndrome typically affects young and middle-aged males who are otherwise healthy, although women can also be affected.

It's also more common in young men of Japanese and south east Asian descent.

To properly understand the underlying cause, it's important to know how the heart cells work.

On the surface of each heart muscle cell are tiny pores, or ion channels. These open and close to let electrically charged sodium, calcium and potassium atoms (ions) flow into and out of the cells.

This passage of ions generates the heart's electrical activity. An electrical signal spreads from the top of the heart to the bottom, causing the heart to contract and pump blood.

More information on how the heart works can be found at the bottom of this page.

Genetic mutation

There are many different genetic mutations that have been linked to Brugada syndrome. The SCN5A gene is most often involved, but only in around athird of cases.

This particular gene provides instructions for making a sodium channel that transports positively charged sodium ions into heart muscle cells.

The mutation in this gene affects theproteins that make up the sodium channels, so they don't work as well. There's a reduced flow of sodium ions into the heart cells, which alters the way the heart beats.

Only one copy of the altered gene in each cell is needed to cause the disorder. In most cases, an affected person has just one parent with the condition.

Not all people with Brugada syndrome have these commongene mutations and there isn't always a family history of it.

Other genes may be involved, and there can be many factors contributing to the development of symptoms, including medicines and imbalances of salts in the body.