Gene Linked to High Blood Pressure Discovered
MONDAY Dec. 29, 2008 -- Researchers have identified a gene variant that may make people more likely to develop high blood pressure.
Although the variant was found in members of the genetically homogeneous Old Order Amish community in Pennsylvania, it is carried by about one of every five white Americans, said Yen-Pei Christy Chang, assistant professor of medicine, epidemiology and preventive medicine at the University of Maryland. Chang is a leader of the research group reporting the new finding in the current issue of the Proceedings of the National Academy of Sciences.
While the variant doesn't have an enormous effect on blood pressure -- it increases levels by about 3.3 points -- it may lead to better treatment of what is formally called hypertension, a major risk factor for cardiovascular problems such as heart attack and stroke, Chang said.
"We're now going back to the Amish again to study how these people react to different hypertension medications," she said. "This can help us find the best medication for hypertension in individual cases."
The discovery was made by use of a new technique called genome-wide association study, done on 542 members of the Old Order Amish, a group that is ideal for such studies, because its members are relatively isolated and share a similar rural lifestyle and diet.
University of Maryland researchers recently reported a different cardiovascular-related genetic variant in the Amish community -- a mutation that seems to reduce blood levels of the fats called triglycerides, thus lowering the risk of heart disease.
In the new study, the researchers scanned the total genetic complement of the Amish participants, looking for individual genetic bits that were associated with blood pressure reading. The scientists zeroed in on the gene variant dubbed STK39. They verified the finding by doing the same scans on participants in four non-Amish studies and a different Amish group.
The gene they found plays a role in blood pressure, because "it regulates the amount of sodium in your body," Chang said. Higher levels of sodium mean greater blood volume and higher blood pressure, she said.
It's not clear how great a role STK39 plays in the overall picture of high blood pressure or how important it might be in treatment of the condition, said Dr. Richard S. Cooper, professor and chairman of preventive medicine at Loyola University's Stritch School of Medicine in suburban Chicago, and another member of the research team.
"At this point, what is important is really a question of what it leads to next," Cooper said. "It is not a major determinant of blood pressure. We are trying to figure out in greater detail what the physiology of it is."
In such genetic studies, there are "two dimensions," Cooper said. "How does it work, and what is the science involved? Is there any way to act on it clinically? Many steps must be taken to determine that."
Posted: December 2008