UK scientists discover 'pacemaker' gene variant

UK researchers have discovered a gene variant that regulates the rhythm of the heart, raising the prospect of new treatments for avoiding heart attacks and heart disease. The finding, by a team led by Imperial College London (ICL), and published in the journal Nature Genetics, may also help doctors to better understand why some patients are more susceptible to heart problems than others.

Heart disease causes almost seven million deaths a year, with almost 100,000 of these occurring in the UK. Half are triggered through sudden changes in rhythm, such as a condition called ventricular fibrillation, which causes the heart to stop.

In the study, the ICL team examined the DNA of over 6,243 Indian Asians and 5,370 Europeans, identifying a gene (called SCN10A) that encodes the proteins (or ion channels) that transmit electrical impulses to the heart's muscles, driving their rhythm. Using electrocardiogram (ECG, a recording of the heartbeat) the team then measured the time it took for electrical signals to travel to different parts of the heart. They found that damage or mutations in the SCN10A gene variant disturbs electrical conduction and therefore, the rhythm of the heartbeat, increasing the risk of ventricular fibrillation and cardiac arrest.

However, the mutation identified in the SCN10A gene is common and, as Dr John Chambers of ICL, who led the team, pointed out, 'the gene variant itself may only have a small effect on a person's risk of having heart rhythm problems'. The team highlights that further research is needed to determine what other mutations may exist in this gene, and whether these variants have a stronger effect than the one reported in the study. Nonetheless, as Dr Chambers said, the study 'gives us important new insight into the mechanisms affecting disordered heart rhythm'.

Professor Peter Weissberg, of the British Heart Foundation, which part-funded the study, said the findings were 'important and exciting'. He went on to say that 'before this, we didn't even realise that the protein produced by this gene was present in heart cells - now it looks like it could be a target for drug development to prevent life-threatening heart rhythm problems'. Team member Professor Jaspal Kooner said the results 'may enable us to predict and diagnose serious heart rhythm disturbances better, and in the future develop improved treatments for preventing ventricular fibrillation'.