Researchers at the University of Maryland School of Medicine have identified a common gene variant that appears to influence people's risk of developing high blood pressure, according to the results of a study being published online Dec. 29, 2008 in the Proceedings of the National Academy of Sciences (PNAS).
The STK39 gene is the first hypertension susceptibility gene to be uncovered through a new technique called a genome-wide association study and confirmed by data from several independent studies. Located on chromosome 2, the gene produces a protein that helps to regulate how the kidneys process salt, which plays a key role in determining blood pressure.
"This discovery has great potential for enhancing our ability to tailor treatments to the individual – what we call personalized medicine – and to more effectively manage patients with hypertension. We hope that it will lead to new therapies to combat this serious public health problem worldwide," says the senior author, Yen-Pei Christy Chang, Ph.D., an assistant professor of medicine and of epidemiology and preventive medicine at the University of Maryland School of Medicine.
But, Dr. Chang says, more research is needed. "Hypertension is a very complex condition, with numerous other genetic, environmental and lifestyle factors involved. The STK39 gene is only one important piece of the puzzle," she says. "We want to determine how people with different variations of this gene respond to diuretics and other medications, or to lifestyle changes, such as reducing the amount of salt in their diet. This information might help us discover the most effective way to control an individual patient's blood pressure."
One in four Americans has elevated blood pressure, or hypertension, which can lead to death or result in complications, such as cardiovascular disease, stroke and end-stage kidney disease. Doctors consider the ideal systolic and diastolic blood pressure to be less than 120/80. (The numbers reflect the pressure of the blood against the arteries when the heart beats and is at rest.) When blood pressure is elevated, doctors recommend lifestyle changes or prescribe medications, such as diuretics, which force the kidneys to remove water from the body, in order to treat the condition.
However, patients respond differently to treatments and finding the best treatment among all the possible ones for specific patients is still a "try and see" process, according to Dr. Chang.
Scientists believe multiple genes are involved in the most common form of high blood pressure called essential hypertension. But, because so many factors affect blood pressure, including diet, exercise and stress levels, it has been difficult to pinpoint a specific gene or group of genes, says the lead author, Ying Wang, Ph.D., a researcher at the University of Maryland School of Medicine.
The University of Maryland researchers identified the link between the STK39 gene and blood pressure by analyzing the DNA of 542 members of the Old Order Amish community in Lancaster County, Pa., scanning approximately 100,000 genetic markers across the entire genome for variants known as single nucleotide polymorphisms, or SNPs, associated with systolic and diastolic blood pressure. The researchers found strong association "signals" with common variants of the serine/threonine kinase gene, or STK39, and confirmed their findings in another group of Amish people and in four other groups of Caucasians in the United States and Europe.