Friday, May 04, 2007

Genetic testing hits the big time?

Almost every article on this discovery emphasized that this gene flaw was found in palefaces. I assume that's because intimations of genetic inadequacy are less controversial when applied to a (transiently) powerful community. In reality they've yet to study the prevalence in non-euros:
BBC NEWS | Health | Heart disease genetic link found
Last Updated: Thursday, 3 May 2007, 18:23 GMT 19:23 UK

... US and Canadian researchers found that up to one in four white people carries the section of DNA which increases the risk of heart disease by around 40%.

A separate study in Iceland found the same genetic variant was linked to a fifth of heart attacks...

... The US/Canadian team found a section of DNA - called an allele - on a specific chromosome that was associated with heart disease.

Their study of 23,000 people, showed that those who carried one copy of this allele have a moderately increased risk of heart disease.

But people who have two copies, which accounts for about 20-25 % of white people, have a 30 to 40% higher risk of heart disease than individuals who carry no copies.

Professor Ruth McPherson, of the University of Ottawa Heart Institute, who worked on the study, said: "The effect is less than that of smoking or having a high cholesterol level....

... The researchers will now check if the findings also apply to people from black and Asian ethnic minorities.

... The Iceland study looked at the same stretch of DNA in 17,000 people.

They also found that more than 20% of people had two copies of the faulty allele.

People with both copies had a 60% increased risk of heart attack, compared with those who with no copies.
The risk factors for premature heart disease of hypertension, diabetes, hyperlipidemia, smoking and male gender are as old as the hills. (Intriguingly family history doesn't usually make the list, I assume it didn't add much to the linear regression models.) For many years we've known that these variables are not fully predictive (I'm thinking 50%, but that's based on ghosts of old memories). Clearly there are other factors to be named, and maybe this gene is one of them.

This is the first mass market gene test candidate I know of, so this is a historic discovery. Once it's commercialized a gene test will be compared to coronary calcium measurement in the management of patients for whom the costs and risks of lipid therapy may outweigh benefits. It will also play a role in deciding who gets cheap life insurance.

BTW, the funny thing about laws that prevent insurers from using gene testing in coverage decsions is that they're unfair ... to insurers. Patients, of course, can use the tests on themselves. If the risks look high, they buy term insurance. If the risks are low, they don't. Poor insurer :-). Really, this stuff is just another shove towards a system of universal minimal health care coverage.

It will be very interesting to learn what this gene codes for. Not only will that open new therapeutic options, we will also suggest the benefit of this allele. It's too common in the euro population to be only dangerous ...

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