The exact role genes play in irregular heart growth is largely unknown
Scientists claim to have found a new genetic basis for why some people develop an enlarged heart, a condition which can result in a cardiac arrest.
Irregular heart growth can be brought on by strenuous exercise, high blood pressure and obesity, but the role played by genes is largely unknown.
Now an international team say they have for the first time linked enlarged hearts with a gene, osteoglycin (Ogn).
Writing in Nature Genetics, they say the findings could mean new treatments.
Work carried out on rodents and some 30 humans indicated that Ogn - which has never before been linked with heart function - regulated the growth of the heart's main pumping chamber, its left ventricle.
When this gene behaves abnormally the heart can become enlarged, putting the person at an increased risk of common heart problems.
Enlarged hearts are found often, but not exclusively, in those who are obese, have diabetes or high blood pressure. People with none of these underlying problems can be affected, as can elite athletes.
A post-mortem diagnosed the problem in Cameroon football midfielder Marc-Vivien Foe, who died in 2003 after collapsing during an international match in France.
The team, which included researchers from the Medical Research Council's Clinical Sciences Centre and the National Heart and Lung Institute at Imperial College, London, noted that at present lowering blood pressure was the only treatment option available.
"But, now that we are unravelling how genes control heart growth, we can gain a better understanding of common forms of heart disease," said Dr Stuart Cook, one of the study authors.
"This could lead to new and more effective ways of treating people."
It is not the first time that genetics have been linked to enlarged hearts: work carried out at University College, London has suggested that genes involved in metabolism may also be linked to the condition.
The British Heart Foundation, which part-funded the research, said it was vital to understand the processes which led to such abnormal growth.
"When a person's heart is continually struggling to meet demand - for example following damage by a heart attack - it may enlarge, lose its elasticity and not pump efficiently," said associate medical director Professor Jeremy Pearson.
"These researchers have used highly advanced technology to discover a new gene - osteoglycin - that is important in controlling heart growth in these conditions. Osteoglycin is now a potential target to aim for with future therapies."