Race and Personalized Medicine


Ron's pill

The Washington Post is running an article on race and personalized medicine on the front page today based in part on the oddly anachronistic concerns of Hamline University law professor Jonathan Kahn. From the article:

Federal examiners have rejected patents for genetic screening tests because the applicants did not explore their effectiveness for different races, adding to the debate about whether race has scientific validity in modern DNA-based medicine.

Some geneticists, sociologists and bioethicists argue that "black," "white," "Asian" and "Hispanic" are antiquated categories that threaten to revive prejudices. Others, however, say that meaningful DNA variations can track racial lines and that ignoring them could deny many benefits of "personalized medicine," which aims to develop tests and treatments tailored to a person's genetic makeup.

"Just because of past misuse — in eugenics and during World War II — doesn't mean we should bury our heads in the sand and shy away from valuable technology that could be leveraged to benefit all of humanity," said Esteban Gonzalez Burchard, who studies biological variations among races at the University of California at San Francisco. …

Jonathan Kahn, a law professor at Hamline University in St. Paul, Minn., discovered the patent rejections when he began sifting through applications, prompted by a 2008 patent office presentation that raised the race issue.

"Constructions of race as genetic are not only scientifically flawed, they are socially dangerous, opening the door to new forms of discrimination or the misallocation of scarce resources needed to address real health disparities," Kahn wrote in a report in the journal Nature Biotechnology in May.

Of course, the concept of race is problematic in all kinds of ways, but is taking into account a patient's ethnicity when considering diagnoses or prescribing medication a bad idea? A number of studies have found that the frequency of genetic variants (alleles) do vary considerably among racial groups. For instance, a 2009 study in the American Journal of Epidemiology looking at 90 gene variants reported: 

In this study, allele frequency (in 88 of 90 genetic variants) and genotype prevalence (in 87 of 90 variants) differed significantly by race/ethnic group….

Because differences in the occurrence of common human diseases among populations reflect variation in genetic factors, environmental factors, and their interaction, population-based genotype data, when coupled with other disease risk factors, will give us better insight into the causes of population differences in the occurrence of various diseases.

Many drugs are now being co-developed with diagnostics that help clinicians target patients who are more likely to respond to a treatment or avoid significant side-effects based on their genetics. So now diagnostic tests can be given to each patient regardless of their ethnicity to get some idea of how well a treatment is likely to work for them. As the Post article acknowledged toward the end: 

Until scientists learn more about individual genetic predisposition, race provides a useful proxy, some say.

But ethnicity as a proxy will be increasingly jettisoned when cheap whole genome sequencing becomes available later in this decade. In that case a patient's ancestry won't matter for clinical purposes at all since physicians will know his or her specific genetic makeup and prescribe treatments accordingly. In the Post article, National Institutes of Health researcher Vence Bonham, Jr. observed: 

"You are truly going to be looking at that individual, whether black, white or Asian. It's the individual's genome that becomes important to their disease risk as opposed to their socially identified race or ethnicity." 

Addendum: Just as I was posting this, I received notification of a new study reported in Nature Genetics that found a "genetic mutation unique to African Americans that could help explain why blacks are so susceptible to asthma." This genetic a variation in the located in a gene called PYHIN1 which is part of a family of genes linked with the body's response to viral infections. Of course, in the future genetic testing will reveal anyone who bears this genetic variant regardless of their ancestry.