Replication of the Wellcome Trust genome-wide association study on essential hypertension in a Korean population

Essential hypertension has a high rate of morbidity and mortality, primarily because of the associated complications. The Wellcome Trust Case Control Consortium recently conducted a genome-wide association study and identified six single nucleotide polymorphisms (SNPs) associated with essential hypertension. The Family Blood Pressure Program later investigated these six SNPs in an attempt to reproduce the aforementioned associations, but only one such association was found. However, this replication study did not include any Asian patients. Therefore, we investigated the association of the six SNPs with hypertension using 7551 unrelated individuals from the Korean Association REsource, a genome-wide association study based on epidemiological cohorts in Korea. We carried out a logistic regression analysis for hypertension status, and a linear regression analysis with systolic blood pressure and diastolic blood pressure as quantitative traits. Even though two SNPs, rs6997709 and rs7961152, were associated with systolic and diastolic blood pressures, respectively, in the quantitative trait association test, no associations were found using a case-control association test. The Korean Association REsource data consisted of two community cohorts (the Ansung and Ansan areas in Korea). The SNP rs7961152 was found to be associated with hypertension risk (OR (odds ratio) =1.286, CI (confidence interval) 1.012-1.636, P=0.040), but only in the Ansan cohort. This study as well as the Family Blood Pressure Program study show that because of the complexity of the genetic architecture, an association study with a larger sample population may be necessary to identify genetic variants that affect hypertension.