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In one of the largest genomic studies ever, an international research consortium identified 29 genetic variations that influence blood pressure. More than half of these variants were previously unknown. The findings provide insights into the biology of blood pressure and may lead to new therapeutic strategies.

High blood pressure, or hypertension, affects over 1 billion people worldwide. It can damage the body in many ways over time, leading to heart disease, stroke, kidney failure and other health problems.

More than 230 researchers across 6 continents scanned the genomes of over 200,000 European people to identify genetic variants that influence systolic and diastolic blood pressure. They followed up by analyzing the genomes of 70,000 people of East Indian, South Asian and African ancestry. The study was funded by NIH’s National Heart, Lung and Blood Institute (NHLBI), National Institute on Aging (NIA) and National Human Genome Research Institute (NHGRI), among others. The results appeared in the September 11, 2011, issue of Nature.

The researchers discovered 16 previously unknown variations. Six were found in genes already suspected of regulating blood pressure. The remaining 10 were found in unexpected locations and provide new clues into how blood pressure is controlled. Individually, the genetic variations increased the risk of hypertension by only a tiny amount. However, for people with multiple variants, the effects were significant.

The researchers developed a blood pressure genetic risk score based on the 29 variants they found. Among people with the top 10% of genetic risk score, 29% had hypertension, compared with 16% of those in the lowest risk group. Higher genetic risk scores were associated with increased blood pressure across ethnic groups. The risk score was also a good indicator of hypertension complications, such as increased thickness of the heart chambers, heart failure, stroke and coronary artery disease.

“This is one of the most important studies of the genetics of high blood pressure to date and a significant step toward finding better therapies for it,” says NHLBI Acting Director Dr. Susan B. Shurin.

A related study by the research group, the International Consortium of Blood Pressure Genome-Wide Association Studies, appeared on the same day in Nature Genetics. This other genome-wide association study identified 4 new genetic regions associated with pulse pressure and 2 linked to mean arterial pressure. The influence of these variants on systolic and diastolic blood pressure turned out to be more complex than expected.

Taken together, these findings suggest new genetic pathways underlying blood pressure regulation. They will also likely open new doors to research into treating high blood pressure.