Anyone who’s ever experienced a painful deep vein blood clot — often triggered by sitting still for a long period of time — learns it’s an emergency. At any moment, a deep vein thrombosis, or clot, can slip into the bloodstream and lodge in the lungs or the brain. Certain gene variants increase the risk of forming such clots.
A paper appearing in Molecular Genetics and Genomic Medicine this week describes the discovery of a genetic variant found primarily among those of African American descent that increases the risk of blood clots.
It's a great example of precision health, said Roxana Daneshjou, MD, PhD, first author on the paper and a recent (weeks-old) graduate of Stanford University School of Medicine. “It’s one of the very few genetic variants in people of African descent that’s been identified and described,” she said. She explained:
We were originally looking at genetic risk factors for dosing warfarin [a common blood thinner] when we found an African American family — a mother and two daughters — who were all on warfarin. Well, we thought that was strange.
It turned out that the three women were all on warfarin for the same reason — multiple deep vein thromboses (blood clots) and pulmonary embolisms (blood clots in the lungs). Deep vein thromboses and pulmonary embolisms are 30 to 60 percent more common among those of African descent than among those of European descent. Yet African Americans with DVT usually lack the genetic risk factors for DVT already known from studying people of European descent.
Maybe, realized Daneshjou and her team, African Americans have different gene variants that also increase the risk of DVT.
“So we looked at the family to try to figure out what mutation might be responsible for this family history of clotting,” said Daneshjou, who worked with professor of medicine and senior author Russ Altman, MD, PhD, and a large team of collaborators.
The researchers found a new mutation in the gene for protein S — a well-know protein involved in normal clotting. The new mutation was more common in African Americans with clotting problems than in those without and nearly absent among people of European descent.
The results shouldn't be interpreted in terms of socially constructed “race,” Daneshjou said. “We don’t ever want to use race in the practice of medicine,” she said. “I like to think about it in terms of genetic ancestry.”
But the study points to the need for additional genetic research in non-European populations, she said:
My hope is that with this federal Precision Medicine Initiative we are going to have more studies in diverse populations and we’re going to find new genetic risk factors. These populations are very severely understudied.
We want to practice medicine in an inclusive way that benefits everyone. To do that, we need to have studied the full diverse range of ancestries.
Previously: The importance of providing patient support in the face of a life-threatening illness, Stanford Medicine X leads precision medicine workshop at the White House and Trial results promising for new anti-clotting drug
Photo by geralt