Two genes that help the body get rid of excess sodium may be important causes of high blood pressure, U.S. scientists reported on Sunday.

They found that people with two particular variants of the genes were at higher risk for high blood pressure.

High blood pressure, also called hypertension, can lead to stroke, heart attack, heart failure and kidney failure, and it tends to run in families. But scientists have struggled to pinpoint genetic traits involved in the condition.

Dr. Christopher Newton-Cheh of Massachusetts General Hospital in Boston and colleagues used genetic data on about 30,000 people from the United States, Sweden and Finland to detect the roles of two genes called NPPA and NPPB.

Those with two copies of one of the “bad” variants were 18 percent more likely to have high blood pressure than people with one or no copies, they wrote in the journal Nature Genetics. People with two copies of the other bad variant had an 11 percent higher risk.

“It does not explain all of high blood pressure,” Newton-Cheh said in a telephone interview.

“It does not explain all of the fact that it runs in families, only a portion of it. And it’s very likely that there are other common genetic differences that contribute to the population variation in hypertension,” Newton-Cheh added.

The two genes produce so-called natriuretic peptides, which are proteins involved in relaxing blood vessels and excreting dietary salt through urine. A high-salt diet is a known risk factor for high blood pressure.

The researchers found that common variants of the two genes left people with lower amounts of these proteins and, as a result, a greater risk of high blood pressure.

Johnson & Johnson unit Scios Inc already makes an intravenous heart failure drug called Natrecor, or nesiritide, that mimics the action of one of these proteins but it is not used for blood pressure control.

A team led by Dr. John Burnett of the Mayo Clinic in Minnesota has tested in lab animals an oral drug that mimics one of the proteins to lower blood pressure, Newton-Cheh said.

The new study indicates such a drug may hold promise to treat people with high blood pressure, Newton-Cheh added.

“There are many therapies for hypertension, although hypertension remains quite difficult to treat and requires many medicines,” Newton-Cheh said.

About half a billion people worldwide have hypertension.

Other risk factors include obesity, a sedentary lifestyle and smoking. Chronic illnesses such as diabetes, kidney disease and high cholesterol also can raise one’s risk.

By Will Dunham
WASHINGTON (Reuters)

Larkin, K. T., and Zayfert, C.
Published with assistance from the foundation established in memory of Amasa Stone Mather of the Class of 1907, Yale College.