Blood pressure linked to genetic variations

Scientists have identified 29 regions of the genome associated with hypertension in people of European origin. Of these, 16 areas contained completely new genes, which had not been previously associated with the risk of developing high blood pressure.

These data arise from two related studies carried out by scientists collaborating on a project led by the International Consortium for Blood Pressure Genome-wide association studies (ICBP-GWAS).

'Your blood pressure is a function of these genes we just identified as well as perhaps a hundred others we haven't found yet', said Dr Aravinda Chakravarti, one of the researchers involved in the study.

Scientists used a GWAS analysis to study differences in SNPs between people with raised and normal blood pressure. SNPs are single letter changes in the genetic sequence, which can provide valuable clues to help pinpoint genes that differ between low-risk and high-risk individuals.

The first study, published in Nature, looked at SNP patterns in 20,000 individuals of European origin. Of the 16 new SNPs identified, six were located in regions suspected to be associated with blood pressure regulation, while the remaining ten were located in regions which have never been linked to blood pressure.

Professor Mark Caulfield, from Barts and The London Medical School, and a lead researcher in this study told the BBC that each of these genetic variants would be in at least five percent of people.

A related study, published in Nature Genetics, sought to identify regions of the genome which might influence pulse pressure (PP) and mean arterial pressure (MAP), high levels of which have been thought to increase risk of cardiovascular disease.

A GWAS involving over 70,000 individuals identified four new PP SNP regions and two new MAP SNP regions. Interestingly, three of the PP regions identified seemed to have opposite influences on systolic (measured while the heart is contracting and pumping blood into the arteries) and diastolic (measured the arteries while the heart is filling with blood between beats) blood pressure. Previously identified PP regions have always shown complementary effects on both types of blood pressure. Both studies provide valuable new clues to physiological processes associated with high blood pressure, and may be useful in the treatment and prevention of cardiovascular disease and hypertension.

However, the British Heart Foundation's medical director, Professor Peter Weissberg warned that genes are 'only part of the puzzle'. 'You are less likely to have high blood pressure if you stick to a healthy diet, do plenty of exercise, and maintain a healthy weight', he said.