Racial Medicine: Not So Fast

Racial Medicine: Not So Fast

The Daily Beast
2008-08-19

Sharon Begley, Senior Health and Science Correspondent
Reuters

Next time you want to start a bar fight, proclaim to everyone within earshot that “race is not real; it is just a social and cultural construct and has no biological validity.” Then duck before you get punched in the face. . . . but as you’re avoiding injury try to hand your would-be assailants a new paper published online this afternoon by the journal Clinical Pharmacology & Therapeutics, which concludes that classifying people by the crude category of race—as in, of African, Asian or European ancestry—for medical purposes, as some people want to do, is really, really stupid…

…Which brings us to the new study. Scientists at the J. Craig Venter Institute got the cool idea of analyzing the genomes of two white guys who, according to the conventional racial categories, belong to the same race. The two are Venter himself and James Watson, co-discoverer of the double-helix structure of DNA. Venter led the private effort to sequence the human genome, winding up in a tie with the public project to do the same.

It happens that the genomes of both men are in the public domain. Watson agreed to have his sequenced and published last year, with Venter right behind. So what do the genomes reveal?

The two men metabolize drugs, including antidepressants, codeine, antipsychotics and the cancer drug tamoxifen, differently. Venter has two functional copies of the CYP2D6 form of the cytochrome P-450 gene, which metabolizes more than 75 percent of drugs, while Watson has two copies of the more-sluggish variant of the gene. That’s rare for Caucasians (only 3 percent of whites have the sluggish version), but common in East Asians (49 percent of whom have it). Funny, Watson doesn’t look Chinese. But if Watson’s doctor decided to use race-based medicine to predict how he would metabolize drugs, she’d say, well, we have a white guy here, and whites rarely have the sluggish version, so I’ll assume Watson doesn’t have it either. As a result, the drug would stay in Watson’s system longer, with stronger effects compared to someone in whom the drug was quickly metabolized and cleared from the body. “It is unlikely that a doctor would guess that optimal drug dosages might differ for Drs. Watson and Venter,” the scientists write.

That’s why Venter and colleagues conclude that race is too crude a proxy for what genetic group—ethnicity or, as biologists say, population—someone belongs to. It is imperative to “go beyond simplistic ethnic categorization,” they write, since that can be seriously—and perhaps fatally—misleading. (In the U.S., some 100,000 people a year die of adverse drug reactions, many caused by an inability to properly metabolize the medication because of a particular CYP2D6 variation.) “Race/ethnicity should be considered only a makeshift solution for personalized genomics because it is too approximate,” they write…

Read the entire article here.

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