[Paleopsych] NYT: Genetic Find Stirs Debate on Race-Based Medicine
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Thu Nov 17 20:42:34 UTC 2005
Genetic Find Stirs Debate on Race-Based Medicine
By 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
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
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
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.
The DG031 drug being tested by DeCode Genetics affects a second gene,
but one that is also involved in control of leukotrienes. Because the
drug reduces leukotriene levels and inflammation, it may help
African-Americans who have the variant of the hydrolase gene. "It
would make scientific, economic and particularly political sense to
have a significant part of the clinical trials done in an
African-American population," Dr. Stefansson said.
A spokeswoman for the black cardiologists' group, which supported the
BiDil trial, said the group's officials were not ready to discuss the
Dr. Troy Duster of New York University, an adviser to the federal
Human Genome Project and a past president of the American Sociological
Association, said he saw no objection to a trial, provided it focused
on African-Americans with the risk-associated variant of the gene and
took into account that people with ancestry from different regions of
Africa might show variations in risk.
But Dr. Charles Rotimi, a genetic epidemiologist at Howard University,
said a separate study of African-Americans would not be desirable. The
variant gene may be overactive in African-Americans because of their
greater exposure to deleterious environments, Dr. Rotimi said.
Dr. Cohn, the inventor of BiDil, said it was "always best to study a
drug in a highly responsive group," rather than testing large
populations where possible benefits to subgroups could be missed.
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