Friday, November 11, 2005

Genetic Find Stirs Debate on Race-Based Medicine

Nicholas Wade:

In a finding that is likely to sharpen discussion about the merits of race-based medicine, an Icelandic company says it has detected a version of a gene that raises the risk of heart attack in African-Americans by more than 250 percent.

The company, DeCode Genetics, first found the variant gene among Icelanders and then looked for it in three American populations, in Philadelphia, Cleveland and Atlanta.

Among Americans of European ancestry, the variant is quite common, but it causes only a small increase in risk, about 16 percent.

The opposite is true among African-Americans. Only 6 percent of African-Americans have inherited the variant gene, but they are 3.5 times as likely to suffer a heart attack as those who carry the normal version of the gene, a team of DeCode scientists led by Dr. Anna Helgadottir reported in an article released online yesterday by Nature Genetics.

Dr. Kari Stefansson, the company's chief executive, said he would consult with the Association of Black Cardiologists and others as to whether to test a new heart attack drug specifically in a population of African-Americans.

The drug, known now as DG031, inhibits a different but closely related gene and is about to be put into Phase 3 trials, the last stage before a maker seeks the Food and Drug Administration's approval.

Last year a drug called BiDil evoked mixed reactions after it was shown to sharply reduce heart attacks among African-Americans, first in a general study and then in a targeted study, after it failed to show efficacy in the general population. The drug, invented by Dr. Jay N. Cohn, a cardiologist at the University of Minnesota, prompted objections that race-based medicine was the wrong approach.

Geneticists agree that the medically important issue is not race itself but the genes that predispose a person to disease. But it may often be useful for physicians to take race into account because the predisposing genes for many diseases follow racial patterns.

The new variant found by DeCode Genetics is a more active version of a gene that helps govern the body's inflammatory response to infection. Called leukotriene A4 hydrolase, the gene is involved in the synthesis of leukotrienes, agents that maintain a state of inflammation.

Dr. Stefansson said he believed that the more active version of this gene might have risen to prominence in Europeans and Asians because it conferred extra protection against infectious disease.

Along with the protection would have come a higher risk of heart attack because plaques that build up in the walls of the arteries could become inflamed and rupture. But because the active version of the gene started to be favored long ago, Europeans and Asians have had time to develop genetic changes that offset the extra risk of heart attack.

The active version of the inflammatory gene would have passed from Europeans into African-Americans only a few generations ago, too short a time for development of genes that protect against heart attack, Dr. Stefansson suggested.

Hat tip, Steve Sailer!


At 11:26 AM, Anonymous Anonymous said...

"development of genes that protect against heart attack"

How would that process work, I wonder?

Normally one associates natural selection with the propagation of advantageous genes. But considering heart attacks, I would expect most people who are affected are well past the age when people form families and have children -- therefore selection would seem to be of no benefit here since they would've already reproduced, i.e. propagated their (bad) genes.

It seems possible that modern civilization and modern medicine themselves would also retard the benefits natural selection offers the gene pool of a population.


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