Blood Pressure Loci Identified with a Gene-Centric Array

Toby Johnson, Tom R. Gaunt, Stephen J. Newhouse, Sandosh Padmanabhan, Maciej Tomaszewski, Meena Kumari, Richard W. Morris, Ioanna Tzoulaki, Eoin T. O'Brien, Neil R. Poulter, Peter Sever, Denis C. Shields, Simon Thom, Sasiwarang G. Wannamethee, Peter H. Whincup, Morris J. Brown, John M. Connell, Richard J. Dobson, Philip J. Howard, Charles A. Mein, Abiodun Onipinla, Sue Shaw-Hawkins, Yun Zhang, George Davey Smith, Ian N.M. Day, Debbie A. Lawlor, Alison H. Goodall, The Cardiogenics Consortium, F. Gerald Fowkes, Gonçalo R. Abecasis, Paul Elliott, Vesela Gateva, The Global BPgen Consortium, Peter S. Braund, Paul R. Burton, Christopher P. Nelson, Martin D. Tobin, Pim van der Harst, Nicola Glorioso, Hani Neuvrith, Erika Salvi, Jan A. Staessen, Andrea Stucchi, Nabila Devos, Xavier Jeunemaitre, Pierre-François Plouin, Jean Tichet, Peeter Juhanson, Elin Org, Margus Putku, Siim Sõber, Gudrun Veldre, Margus Viigimaa, Anna Levinsson, Annika Rosengren, Dag S. Thelle, Claire E. Hastie, Thomas Hedner, Wai K. Lee, Olle Melander, Björn Wahlstrand, Rebecca Hardy, Andrew Wong, Jackie A. Cooper, Jutta Palmen, Li Chen, Alexandre F.R. Stewart, George A. Wells, Harm-Jan Westra, Marcel G.M. Wolfs, Robert Clarke, Maria Grazia Franzosi, Anuj Goel, Anders Hamsten, Mark Lathrop, John F. Peden, Udo Seedorf, Hugh Watkins, Willem H. Ouwehand, Jennifer Sambrook, Jonathan Stephens, Juan-Pablo Casas, Fotios Drenos, Michael V. Holmes, Mika Kivimaki, Sonia Shah, Tina Shah, Philippa J. Talmud, John Whittaker, Chris Wallace, Christian Delles, Maris Laan, Diana Kuh, Steve E. Humphries, Fredrik Nyberg, Daniele Cusi, Robert Roberts, Christopher Newton-Cheh, Lude Franke, Alice V. Stanton, Anna F. Dominiczak, Martin Farrall, Aroon D. Hingorani, Nilesh J. Samani, Mark J. Caulfield, Patricia B. Munroe

Raised blood pressure (BP) is a major risk factor for cardiovascular disease. Previous studies have identified 47 distinct genetic variants robustly associated with BP, but collectively these explain only a few percent of the heritability for BP phenotypes. To find additional BP loci, we used a bespoke gene-centric array to genotype an independent discovery sample of 25,118 individuals that combined hypertensive case-control and general population samples. We followed up four SNPs associated with BP at our p < 8.56 × 10(-7) study-specific significance threshold and six suggestively associated SNPs in a further 59,349 individuals. We identified and replicated a SNP at LSP1/TNNT3, a SNP at MTHFR-NPPB independent (r(2) = 0.33) of previous reports, and replicated SNPs at AGT and ATP2B1 reported previously. An analysis of combined discovery and follow-up data identified SNPs significantly associated with BP at p < 8.56 × 10(-7) at four further loci (NPR3, HFE, NOS3, and SOX6). The high number of discoveries made with modest genotyping effort can be attributed to using a large-scale yet targeted genotyping array and to the development of a weighting scheme that maximized power when meta-analyzing results from samples ascertained with extreme phenotypes, in combination with results from nonascertained or population samples. Chromatin immunoprecipitation and transcript expression data highlight potential gene regulatory mechanisms at the MTHFR and NOS3 loci. These results provide candidates for further study to help dissect mechanisms affecting BP and highlight the utility of studying SNPs and samples that are independent of those studied previously even when the sample size is smaller than that in previous studies.