Heart risk 'governed by genetics'

The research centred on twins

Genetics appears to be the most important factor in determining who is at risk of blood clots, the major cause of heart attacks, researchers have found.

A UK team used twins to examine whether genetic or environmental factors play the most significant role in determining the risk.

We know from these findings that genes are the major influencing factor

Dr Tim Spector, Guy's and St Thomas' Hospital

Coronary heart disease is one of the biggest killers in the UK. An increase in cases has been partly blamed on poor diet and unhealthy lifestyles.

Blood samples were taken from 500 pairs of twins at Guy's and St Thomas' Hospital in London.

The samples were analysed to find out what concentration they contained of a number of different plasma proteins.

These proteins are the ingredients in blood that cause clotting in arteries, and are increased in people who are likely to develop heart disease.

The tests were carried out at the Molecular Vascular Medicine Department at Leeds University.

Researchers found that genetic make-up was responsible for up to 75% of the variations in the level of these clotting factors.

However, concentrations also increased with age.

Identical twins

Dr Tim Spector, director of the twin research unit at Guy's and St Thomas' Hospital, said: "We have known for a long time that family background is an important risk factor for heart disease, but not the extent to which this depends on shared environments or shared genes.

"As identical twins share exactly the same genes and non-identical twins half the same genes as each other, twin studies are extremely useful in separating these genetic and environmental components.

"We know from these findings that genes are the major influencing factor and that once these have been pinpointed we can develop early diagnostic tests and novel therapies targeted specifically to modify the action of these genes."

However, Dr Spector stressed that environmental factors were still important.

He said it was particularly important that people with a genetic susceptibility to heart disease led a healthy lifestyle.

Belinda Linden, the British Heart Foundation's head of medical information, said: "In recent years there have been rapid developments in research into the various processes affecting blood clotting and we are now beginning to recognise that hereditary factors can contribute to some conditions where blood clotting plays an important part.

"When we are fully able to identify those people with genetic abnormalities in clotting factors we may be able to help diagnose and treat those people most at risk."

The research is published in The Lancet medical journal.

The Twin Research Unit is looking to extend their work to identify the exact genes responsible in this and other disease areas and would like to hear from Twin Volunteers aged over 18, either identical or particularly non-identical who can call the twin hotline on 0990-770099.