Medical

The Mystery of Genetics in Multiracial Health Care
By Kendall Baldwin

TPR President Kendall Baldwin

Since the Civil Rights movement of the 1960s the population of our country has gone through a huge shift. According to the U.S. Census, the number of multiracial babies born each decade is increasing more than the number of single race babies. It is estimated that the multiracial population in the U.S. will reach 21 percent by 2050.

Despite this shift, multiracial people are almost invisible in our healthcare system. While, thanks to knowledge of DNA, scientists now believe that race is social not scientific, there is still a great deal of debate over whether “race” is a meaningful factor in medicine. Therefore, I would like to study genetic health risks in the multiracial population.

There are several medical areas of special concern for multiracial people. For example, many multiracial children are at risk for improper medical screening for diseases that affect certain racial groups. Furthermore, it is not known whether multiracial people even have a predisposition to any genetic diseases. Another area of concern is bone marrow transplants for patients with leukemia and other blood diseases, where the best chance of a match is within the same genetic pool of potential donors. But the area that most interests me is the way multiracial people respond to different medications. By not including multiracial people in clinical trials, the Federal Drug Administration (FDA) and pharmaceutical companies put us at risk for overdosing or under-dosing on a drug every day. I would specifically like to study genetic predictors that help identify whether multiracial people may have higher or lower efficacy in response to a drug. As a multiracial female with Type 1 Von Willebrand Disease, a hereditary bleeding disorder caused by a defect on chromosome 12, I have a very personal interest in this area of research.

While genetic and environmental factors, such as diet, housing and occupation, affect drug response there is definitely a proven genetic relationship between geographic ancestry, and probably race, and the response to drugs. Researchers have, therefore, developed markers that can be used for geographic ancestry testing and have found some genetic differences in prevalence between people of different ancestry, including some that are connected to drug response.

Dr. Wylie Burke is Professor and Chair of the Department of Medical History and Ethics at the University of Washington. She is also Principal Investigator of the University of Washington Center for Genomics and Healthcare Equality, an NIH-funded Center of Excellence in Ethical, Legal, and Social Implications (ELSI) Research. In a speech to the Secretary’s Advisory Committee on Genetics, Health, and Society, Dr. Burke gave an example about the gene CYP 2C9 and its variants associated with reduced dose requirements for the drug Warfarin. Warfarin is a drug used to prevent blood clots from forming. She told the committee about research, which found that in people of European ancestry, the prevalence of variants associated with reduced Warfarin dose requirements was about 36 percent; for people of Native American ancestry it was 10 percent; for those of African ancestry it was 8 percent and for those of Asian ancestry it was 4 percent. People who have these variants in that gene require significantly lower doses of blood coagulation. They also have a higher likelihood of bleeding complications. Therefore, it is critical to study this genetic trait in every monoracial and multiracial population.

But, where do multiracial people fit in? One of my parents is of European ancestry and the other is of African ancestry. If I were to require Warfarin, would I take an average of the data to predict a variance of 22? Maybe I inherited this variance from one parent rather than the other and should expect a variance of 36 percent – or 8 percent? How would we determine my dosage? No one knows. Having now learned a bit about the significance of CYP 2C9 variants, I wonder if there are similar variants that might affect the drug response for Thrombin (activated Factor II), AMICAR¨ (aminocaproic acid), or desmopressin acetate, the drugs often used to treat my disorder. And, if there are, will it ever be learned what the prevalence of variants are for a patient of my particular multiracial background? It won’t, unless multiracial subjects of different mixes are included in all studies that compare racial or geographic ancestry and ethnicity.

In an age where there is a trend toward personalized medicine best suited to the individual patient, this type of research is needed more than ever before. Our country needs to adapt in many different ways to keep up with our increasingly multiracial society. As the face of our nation changes, so must the subjects of genetic research.

References:

  • Published notes from the U.S. Department of Health and Human Services Secretary’s Advisory Committee on Genetics, Health, and Society. Eighth Meeting held on Friday, October 20, 2005
  • “Using Biologic Markers in Blood to Assess Exposure to Multiple Environmental Chemicals for Inner-City Children 3Ð6 Years of Age” by Ken Sexton, John L. Adgate, Ann L. Fredrickson, Andrew D. Ryan, Larry L. Needham, and David L. Ashley