When Diversity Means Better Medicine
By tapping into more diverse genomes, researchers are gaining novel insights into disease and drug safety.
For a variety of historical and logistical reasons, the vast majority of genomics research, to date, has been done in European populations. A 2016 analysis in the journal Nature found that 81 percent of participants in genetic research are of European ancestry.
But in recent years scientists are pushing to expand research into more diverse groups to gain broader insights into the genetic links to disease and to drug responses in different populations. “Studying diverse populations gives us a lot more information about genetic variants associated with disease,” says Katrina Loomis, a Senior Director in Pfizer's Genome Sciences and Technologies Group. “We’re collaborating worldwide with academic institutions to tap into insights from human genetic diversity,” she adds.
Human genetics research has become borderless. Scientists have found, for example, that the Inuit in Greenland carry a unique genetic mutation that increases their risk of type 2 diabetes by 50 percent. At Pfizer, researchers are currently working with academic institutions collaborators to examine genetic variants in Pakistani communities to gain insights into type 2 diabetes and cardiovascular disease. And another partnership is looking at genetics of inflammatory bowel disease in African American and Hispanic populations in addition to the Caucasians.
Peering Into Bottleneck Populations
By expanding into diverse populations, researchers are gaining a better understanding of genetic variations that may give them more confidence to pursue drug targets. Researchers are studying individuals in Finland who have a beneficial mutation in the SLC30A8 gene that provides protection against developing type 2 diabetes. While the Finnish are of European ancestry, they’re what’s known as a “bottleneck population” — a historically isolated group that have some unique genetic mutations not seen as frequently in the general population. “Isolated populations have a unique genetic architecture due to their relative segregation,” says Loomis, who is based at Pfizer's Kendall Square site in Cambridge, Mass. “Research using bottleneck populations nicely complements the insights gained from populations of general European descent.”
By observing the effects of the SLC30A8 mutation in the Finnish, researchers have more promising data to pursue this protein as a target for diabetes therapies. “If we can find human causal evidence that links our drug target to a disease or phenotype of interest, we have more confidence that we are going to have efficacy by modulating the target, that it’s going to be a clinically meaningful treatment for that disease,” says Loomis.
Ethnic Groups in Clinical Trials
Honing in on specific ethnic groups can also provide greater insights into the safety of drugs during the clinical trial stages. Inspired by the observation that not all ethnic groups may experience adverse events at the same rate, scientists are conducting multi-ethnic studies to find the genetic variants associated with those patterns. “If we find that a certain patient population is more prone to a certain adverse event, we can study the specific biological connection responsible for that risk, and look to address it when we develop the next generation of a drug,” says Nan Bing, Head of Inflammation and Immunology Genetics in Genome Sciences & Technologies.