They identified the gene's role in high blood pressure susceptibility by analysing the genes of 542 people in the insular Old Order Amish community in Lancaster County, Pennsylvania. The researchers confirmed the findings by looking at the genes of another group of Amish people as well as four other groups of white people in the US and Europe.

About 20 per cent of the people studied had either one or two copies of this particular variant, the researchers said. The gene produces a protein involved in regulating the way the kidneys process salt in the body -- a key factor in determining blood pressure, the researchers said.

Yen-Pei Christy Chang, who led the study appearing in the journal Proceedings of the National Academy of Sciences, said the findings could lead to the development of new high blood pressure drugs targeting the activity of STK39.

“What we hope is that by understanding STK39 we can use that information for personalised medicine, so we can actually predict which hypertensive patients should be on what class of medication and know that they will respond well and have minimal risk for side effects,” Chang said. People with high blood pressure are more likely to develop heart attacks, heart failure, strokes and kidney disease.

While STK39 may play a pivotal role in some people, Chang said numerous other genes also may be involved. Many factors are involved in high blood pressure such as being overweight, lack of exercise, smoking and too much salt in the diet.

Several different types of medications are used to treat high blood pressure, including diuretics, beta blockers, ACE inhibitors, calcium channel blockers and others. Their effectiveness varies depending on the person, and doctors have a hard time knowing which is best for a particular patient.

Chang said the researchers want to determine how people with different versions of this gene respond to various drugs and lifestyle interventions like cutting the amount of salt in the diet.

The Lancaster Amish are seen as ideal for genetic research because they are a genetically homogenous people whose ancestry can be traced to a small group who arrived from Europe in the 1700s. In addition to genetic similarity, they also maintain similar lifestyles in their close-knit rural communities.