It sounds like science fiction: genetically-based medicine offering drugs that
work best for you because they perfectly suit your racial profile. Two years
ago, the US Food and Drug Administration (FDA) approved the first “ethnic”
drug specifically for one racial group.
Called BiDil, it was shown to increase survival among African-Americans with
advanced heart disease. It was hailed as a leap into a new era of
“pharmacogenomics”, in which drugs would work more effectively because they
were tailored to your genetic profile.
Then an Icelandic company called Decode said it had detected a version of a
gene that significantly raises the risk of heart attack in
African-Americans. The company reported in Nature Genetics that the
6 per cent of African-Americans with the variant gene were 3.5 times as
likely to suffer a heart attack, and said that the gene could be suppressed
by specifically targeted drugs.
On the face of it, these are exciting developments. But now, in the week that
the genetic pioneer James Watson caused uproar by saying that people of
African origin were not as intelligent as Caucasians, serious questions are
being raised about whether racially targeted medicine offers more hype than
hope. Experts gathering for a big genomics conference hosted by the Economic &
Social Research Council (ESRC) in London next week are keen to prescribe a
salty dose of realism with our highly sugared genetic meds.
Sickle cell anaemia as a “black disease”
Race-based medicine revolves around the assumption that racial groups are
likely to have common genetic characteristics, and some of these genetic
commonalities will also bring some common susceptibility to certain
diseases.
The most well-known example is sickle cell anaemia, an inherited blood
disorder. It is caused by a defect in the gene that makes haemoglobin (a
component of red blood cells), making it defective and poor at carrying
oxygen.
Since it was identified in 1910 the disorder has been characterised as a
“black disease” because the genetic characteristic causing the disease
(which also provides some protection against malaria) is common in black
populations. Similarly, high rates of prostate disease in Afro-Caribbean men
have prompted researchers to investigate cancer genes for this group.
New excitement about the potential of easy genetic testing techniques has, as
a result, caused an explosion of interest in racially targeted medicine, and
its potential for screening and treating those most vulnerable.
A recent report in Forbes magazine predicted that we will soon have
home kits “as simple and cheap as a pregnancy-test dipstick” for genes for
stress, pleasure, irritability, aggression, suicide, alcoholism and sexual
proclivities.
But some scientists suggest that testing your genetic profile on the basis of
race may not only be flawed but also unethical. Take sickle cell. It is also
common in people of Greek, Italian, Indian and Latin American ancestry and
academics such as the anthropologist Melbourne Tapper, from the University
of Texas, believe that our perceptions of the disease as “racial” have been
driven by notions such as genetic purity and superiority.
And Dr Troy Duster, a former president of the American Sociological
Association, has urged geneticists to slow down in their search for links
between genes, disease and race in a book called Backdoor to Eugenics.
Fear of gene-testing’s darker aspects led the US House of Representatives to
pass a law banning employers and insurers from discriminating against people
on the basis of genetic tests.
The whole field may be based on a misconception. Genetically speaking, nothing
differentiates one race from another. There is no African gene, no Causasian
gene, no Asian gene. Genetic differences exist, and these get passed on to
offspring, but generally the differences don’t occur neatly along neat
racial lines. Human beings share 99.99 per cent of their genetic make-up,
regardless of race, and the variants that occur in the remaining 0.01 per
cent of the genome are seen across all ethnic populations.
Ethnic populations are genetically variable
Angus Clarke, a professor of medical genetics at Cardiff University, who will
address the ESRC conference, says there are problems with the basic
effectiveness of identifying treatments for people on the basis of their
race. “Using people’s ethnic background should be getting less and less
important,” he says. “You are merely talking about probabilities; that if
someone is from population X, they are more or less likely to have that gene
variation. But populations are so variable and the way people label
themselves ethnically is so varied that the amount of information you get is
pretty poor.”
Indeed, a Columbia University study in the American Journal of Public
Healthlast year concluded that even among Ashkenazi Jews, a group
normally considered genetically discrete, there was no point seeking
specific racial genes for breast cancer because the Ashkenazis had bred with
people from other ethnic groups. The problem is magnified many times among
African-Americans, a self-identifying population with a rainbow of genetic
backgrounds. So how come we have the African-American-only heart drug BiDil?
The drug, and the way it was tested, are not quite as they initially seem.
Although the clinical trial for it showed significant results in
African-American patients, its many critics point out that this doesn’t mean
much because it was tested only on black patients. The FDA’s approval of
BiDil was based on a clinical trial that enrolled only self-identified
African-Americans and did not compare their health outcomes with those of
other ethnic or racial groups. Nor is BiDil a true “pharmacogenomic” drug.
It is a pill that combines two generic drugs that dilate blood vessels, and
both have been used for more than a decade to treat heart failure in people
of all races.
Critics, including Professor Clarke, say that BiDil’s approval as a “racial”
drug has more to do with marketing skill than genes.
“The FDA decision is incredibly controversial. Health professionals have been
quite unhappy with it, and it’s seen as collusion between drug licensers and
drug companies,” he says. “I don’t think that opposition to BiDil is going
to wither away.”
Meanwhile, the current ability of genetic testing to tell you much that is
useful for your health has also been questioned. Paula Saukko, a sociologist
who has worked for the ESRC’s centre for genomics in society, has studied
companies selling genetic-testing products direct to consumers in Europe via
the internet. He says the online sellers often wriggle between legal
definitions to avoid regulatory trouble.
“They want their genetic-testing products to sound special or miraculous but,
at the same time, they don’t want to be caught red-handed making outrageous
claims,” she says. “They tend to skirt around the issue of what their tests
might identify – whether it’s a genuine genetic predisposition or just some
kind of ‘susceptibility’. So they may point to a ‘gene for heart disease’ or
a ‘gene for cancer’, though the association is very small and the clinical
tests supporting the link have not been replicated.”
What we really need are cheap and accurate genetic-testing techniques to
profile your susceptibility to disease, and what drugs will suit you best,
as an individual, not as a race. With no such test on the horizon, the worry
is that the marketing men will spread a misleading and potentially dangerous
idea of what genetics really means.
GLOBAL MORTALITY
The leading causes of death in countries across the globe, according to the
World Health Organisation database:
China Stroke
Dominican Republic HIV/Aids
Ethiopia Respiratory disease, such as asthma or chronic obstructive
pulmonary disease
France Heart disease
Germany Heart disease
Iran Heart disease
Iraq Respiratory disease
Israel Heart disease
Japan Stroke
Kenya HIV/Aids
Mongolia Stroke
Peru Heart disease
Russia Heart disease
South Africa HIV/Aids
Switzerland Heart disease
Thailand HIV/Aids
UK Heart disease
US Heart disease
Zimbabwe HIV/Aids
