Early heart attack clue in genes

Many factors are involved in the development of heart disease

Scientists looking for the reasons why some patients have heart attacks well before middle age say a genetic variation may partly explain it.

The research team, from the Cleveland Clinic Foundation, believe they have found four genetic variations which either increase or decrease the risk of early heart attack.

As early heart disease is a very pronounced version of the illness, the team hopes that their work could eventually help millions of other heart disease patients.

They unscrambled the genetic makeup of more than 350 heart disease victims and more than 400 unaffected people.

It may help us identify more accurately those people who are at the highest risk of heart disease, and use our expensive drugs on them

Professor Steve Humphries, University College London

The heart disease victims all came from families in which two members had either had a heart bypass operation or a heart attack before the age of 45 in men, and 50 in women.

Their investigation eventually homed in on four genes which regulate a key body chemical called thrombospondin.

This protein is important because it influences blood clotting, new blood vessel growth and the response of vessels to cholesterol - all key factors in the sequence of events which can lead up to a heart attack.

They found that the presence of a variant of one of the genes, called thrombospondin-4, increased the risk of a heart attack by 89%.

In contrast, having a mutated version of another gene, thrombospondin-2, actually decreased the risk of a heart attack by 69%.

'Smoking gun'

Those with two copies of one particular variant thrombospondin gene were much more likely to have early heart disease.

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Professor Eric Topol, chairman of cardiovascular medicine at the clinic, said that the team had been searching for "smoking gun" evidence for mutated genes which could increase heart disease risk.

He said: "You could say we stumbled into this thrombospondin theory.

"This study is the largest genotyping of cardiovascular risk to date, and one of the many approaches to unravel the most important cause of death and disability in our society."

He said that the findings, while not showing a need for population screening for the variant genes, did warrant further investigation.

More research

A British expert in heart disease genetics, Professor Steve Humphries from University College London, said that there were currently few candidate genes for early heart disease, except for a single gene disorder which caused very high cholesterol levels.

Professor Humphries, Director of the Centre for Cardiovascular Genetics said that the latest finding - published in the journal Circulation - needed to be backed by other studies with the same result.

"It may help us identify more accurately those people who are at the highest risk of heart disease, and use our expensive drugs on them.

"But it won't be effective to screen people for this gene."