High blood pressure or hypertension affects more than one in three people worldwide and is a major cause of strokes, heart attacks and heart failure [1]. The degree with which blood pressure traits can be inherited suggests a genetic component. However, limited consistent evidence of genes associated with blood pressure have been produced. A new study in the journal Nature Genetics reports for the first time a number of genes showing significant associations with blood pressure and hypertension across the genome [2].

Although large-scale genome-wide association studies (GWAS) have been used successfully to identify genes associated with common diseases and traits, studies on blood pressure or hypertension have failed to identify loci at a genome-wide significant threshold (p-value < 5 x 10^-8). The significance of GWAS data relies on several variables, including the accuracy of phenotypic measures, density of markers and size of the study population. Thus, if blood pressure variation in the general population is due to multiple genetic factors with small effects, a very large sample size is needed to identify them.