New York Times

March 20, 2003

2 Scholarly Articles Diverge on Role of Race in Medicine
By NICHOLAS WADE

Responding to recent advances in decoding DNA that have thrown light into a
murky corner of genetics, two articles in The New England Journal of
Medicine today take different views on whether race is a meaningful factor
in medicine.

In addition, a staff-written commentary suggests that the journal's own view
on the subject may have softened in the two years since it ran an editorial
attacking "the fallacy of race as a scientific concept."

The issue of race and medicine arises because certain diseases are more
common in some ethnic groups than others. One well-known instance is sickle
cell anemia, most prevalent in Africans, and another is Tay-Sachs, more
common among Jews. 

A view widespread among many social scientists, endorsed in official
statements by the American Sociological Association and the American
Anthropological Association, is that race is not a valid biological concept.
But biologists, particularly the population geneticists who study genetic
variation, have found that there is a structure in the human population. The
structure is a family tree showing separate branches for Africans,
Caucasians (Europe, the Middle East and the Indian subcontinent), East
Asians, Pacific Islanders and American Indians.

Biologists, too, have often been reluctant to use the term "race." But this
taboo was broken last year by Dr. Neil Risch, a leading population
geneticist at Stanford University.

Vexed by an editorial in The New England Journal that declared that race was
"biologically meaningless," Dr. Risch argued in the electronic journal
Genome Biology that self-identified race was useful in understanding ethnic
differences in disease and in the response to drugs.

Race corresponded broadly to continental ancestry and hence to the branches
on the human family tree described by geneticists, he said.

Expanding this argument today, Dr. Risch and nine co-authors say that
ignoring race will "retard progress in biomedical research."

Racial differences have arisen, they say, because after the ancestral human
population in Africa spread throughout the world 40,000 years ago,
geographical barriers prevented interbreeding. On each continent, under the
influence of natural selection and the random change between generations
known as genetic drift, people would have diverged away from the common
ancestral population, creating the major races. Within each race, religious,
cultural and geographical barriers fostered other endogamous, or inbreeding,
populations that led to the ethnic groups.

These divisions in the human population, though very slight in comparison
with the genetic variation inherited in common from the ancestral
population, can be important in understanding many diseases, Dr. Risch says.
Many rare diseases are often specific to single ethnic groups because of a
founder effect: They were present in the founder and became more noticeable
as the group, while remaining endogamous, grew in number. Many such diseases
are known among such well-studied groups as Ashkenazi Jews, French Canadians
and the Amish. 

Common diseases are found worldwide. But though much less is known about
them, they may be caused by different genes in different racial groups, Dr.
Risch says. In Caucasians, mutations in a gene called CARD15 make a person
susceptible to Crohn's disease, but Japanese with Crohn's disease have none
of these mutations. Presumably a different gene, yet to be found,
contributes to Crohn's in Japanese.

"It may be tempting to abandon the notion of race altogether," Dr. Risch and
his colleagues write, especially if attention to racial differences should
perpetuate discrepancies, but because of the leading clues provided by race
to the cause and treatment of disease, such a course "would be detrimental
to the very populations and persons that this approach allegedly seeks to
protect."

An opposing article by Dr. Richard S. Cooper, of the Loyola Stritch School
of Medicine in Maywood, Ill., is more skeptical. Doctors have been too
quick, Dr. Cooper and his co-authors write, to suggest genetics as the
reason for the greater susceptibility of African-Americans to certain
diseases, when the true reason may be social factors.

Dr. Cooper, an expert in the epidemiology of heart disease, agrees that some
rare diseases are particular to certain populations, but he says the genetic
variants that underlie common diseases are not.

"We can expect genomics increasingly to negate the old-fashioned concept
that differences in genetic susceptibilities to common diseases are racially
distributed," he says. For example APOE4, a genetic variant that contributes
to Alzheimer's disease, is found in all populations, he writes.

But even with APOE4, Dr. Risch says, knowledge of racial background provides
important insights because the risk conferred by the gene varies by race.
Inheriting two APOE4 genes, one from each parent, raises the risk of
Alzheimer's 33 times in Japanese populations, 15 times in Caucasians and
only 6 times in Africans. This suggests that some unknown factor modifies
the effect of the APOE4 gene in different races, he says.

Dr. Cooper is also concerned that if medical geneticists were to prove that
race is a valid biological concept, then social and political aspects of
race, some not so benign, might also seem to be validated.

"Race already has a meaning," he writes. "To invoke the authority of genomic
science in the debate over the value of race as a category of nature is to
accept the social meaning as well."

Two years ago an editorial by Robert S. Schwartz, deputy editor of The New
England Journal, dismissed the idea of race as a scientific concept. But in
today's issue another deputy editor, Elizabeth G. Phimister, says only that
it "remains to be seen" whether continental-based racial definitions will
help track the variant genes that cause common diseases.

Dr. Phimister concludes that it would be "unwise to abandon the practice of
recording race when we have barely begun to understand the architecture of
the human genome" and its clues to the genetic basis of disease.

She said in an e-mail message, however, that an editorial in the journal
"conveys the views of the author only, rather than views germane to journal
policy."

Dr. Risch said in an interview that anxiety about the genome and race might
have arisen among minorities who did not always feel in control of their own
genetic information. Despite initial fears of discrimination, he said, Jews
had taken charge of the information about diseases more common in Ashkenazis
and now accepted its usefulness.

"The more minorities we can get doing the research, the more these issues
will dissipate," he said.

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