Scots team help identify genes linked to heartbeat

SCOTTISH scientists have helped identify genes that are linked to the human heartbeat in a study that is likely to lead to major developments in the treatment of cardiac problems.

An international team of scientists have pinpointed 22 genes that are associated with the electrical impulses that make the heart beat.

The discovery is the first step on the road to improved treatments for people with heart problems and better identification of people who have undiagnosed and potentially dangerous irregularities in their heartbeat.

The research was led by the University of Washington and involved more than 100 scientists in the UK, Europe and USA, including teams at the universities of Edinburgh and Glasgow.

Normally, signals start from specialised muscle cells, travel across the heart and cause rhythmical muscle contractions - a system called cardiac conduction. The signals register as the pulsating wave seen on heart monitors.

Abnormalities in cardiac conduction, particularly in the ventricles of the heart, can be dangerous. When severe, cardiac pacemakers must be fitted to patients to ensure regular cardiac electrical activity throughout the heart.

Abnormal ventricular conduction also makes people more susceptible to heart failure, sudden death and death due to heart disease.

Researchers have known for some time that genetic factors contribute to electrical activity in the heart, including conduction of the electrical signal throughout the heart chambers.

This study focuses on several previously unsuspected regions in the genome that are associated with cardiac electrical activity.Researchers were able to identify genetic associations with cardiac ventricular conduction in 22 regions of the genome.

The research was funded by the National Institutes of Health, the Medical Research Council (MRC), the Chief Scientist Office and the Royal Society.

More than 50,000 people - including 700 volunteers involved in the Edinburgh University run Medical Research Council Human Genetics Unit studies in Orkney - have contributed to the findings, which are published today in the journal Nature Genetics.

The Orkney islands' isolated population is particularly appropriate for DNA studies because it is a very stable, with some families going back eight generations, and the residents also share a much greater degree of environmental factors such as diet and lifestyle than mainland populations do.

Dr Jim Wilson, Royal Society University research fellow at the University of Edinburgh, said: "This study demonstrates the great potential of modern genetics to help us better understand how our heart's electrical system works at the molecular level."This is very important as heart conduction abnormalities increase the risk of heart failure and sudden death: this knowledge will be used in the hunt for new treatments."

Dr Caroline Hayward of the MRC Human Genetics Unit in Edinburgh, who was involved in the analysis of the study, said: "By understanding more about the biological processes that control every heartbeat, we can begin to have real insight into causes and potential treatments for people at increased risk of sudden death and cardiac mortality."

The breakthrough is likely to lead to a series of new studies that will examine how this genetic information can help identify and treat heart problems. It could, however, be several decades before it results in new treatments for heart conditions.