Targeting 160 Candidate Genes for Blood Pressure Regulation with a Genome-Wide Genotyping Array

The outcome of Genome-Wide Association Studies (GWAS) has challenged the field of blood pressure (BP) genetics as previous candidate genes have not been among the top loci in these scans. We used Affymetrix 500K genotyping data of KORA S3 cohort (n = 1,644; Southern-Germany) to address (i) SNP coverage in 160 BP candidate genes; (ii) the evidence for associations with BP traits in genome-wide and replication data, and haplotype analysis. In total, 160 gene regions (genic region±10 kb) covered 2,411 SNPs across 11.4 Mb. Marker densities in genes varied from 0 (n = 11) to 0.6 SNPs/kb. On average 52.5% of the HAPMAP SNPs per gene were captured. No evidence for association with BP was obtained for 1,449 tested SNPs. Considerable associations (P<10−3) were detected for the genes, where >50% of HAPMAP SNPs were tagged. In general, genes with higher marker density (>0.2 SNPs/kb) revealed a better chance to reach close to significance associations. Although, none of the detected P-values remained significant after Bonferroni correction (P<0.05/2319, P<2.15×10−5), the strength of some detected associations was close to this level: rs10889553 (LEPR) and systolic BP (SBP) (P = 4.5×10−5) as well as rs10954174 (LEP) and diastolic BP (DBP) (P = 5.20×10−5). In total, 12 markers in 7 genes (ADRA2A, LEP, LEPR, PTGER3, SLC2A1, SLC4A2, SLC8A1) revealed considerable association (P<10−3) either with SBP, DBP, and/or hypertension (HYP). None of these were confirmed in replication samples (KORA S4, HYPEST, BRIGHT). However, supportive evidence for the association of rs10889553 (LEPR) and rs11195419 (ADRA2A) with BP was obtained in meta-analysis across samples stratified either by body mass index, smoking or alcohol consumption. Haplotype analysis highlighted LEPR and PTGER3. In conclusion, the lack of associations in BP candidate genes may be attributed to inadequate marker coverage on the genome-wide arrays, small phenotypic effects of the loci and/or complex interaction with life-style and metabolic parameters.

[1]  Eric Boerwinkle,et al.  Replication of the Wellcome Trust genome-wide association study of essential hypertension: the Family Blood Pressure Program , 2008, European Journal of Human Genetics.

[2]  Nilesh Samani,et al.  Genome-wide mapping of human loci for essential hypertension , 2003, The Lancet.

[3]  S. Ghosh,et al.  Alpha 2-adrenergic receptor gene polymorphism and hypertension in blacks. , 1995, American journal of hypertension.

[4]  Michael O'Leary,et al.  A genetic polymorphism of the alpha2-adrenergic receptor increases autonomic responses to stress. , 2004, Journal of applied physiology.

[5]  M. Daly,et al.  Genetic Mapping in Human Disease , 2008, Science.

[6]  Manuel A. R. Ferreira,et al.  PLINK: a tool set for whole-genome association and population-based linkage analyses. , 2007, American journal of human genetics.

[7]  C. Gieger,et al.  KORA-gen - Resource for Population Genetics, Controls and a Broad Spectrum of Disease Phenotypes , 2005, Gesundheitswesen (Bundesverband der Arzte des Offentlichen Gesundheitsdienstes (Germany)).

[8]  D. D. de Luis,et al.  Influence of Lys656Asn polymorphism of the leptin receptor gene on insulin resistance in nondiabetic obese patients. , 2008, Journal of diabetes and its complications.

[9]  C. Bouchard,et al.  A C‐1291G polymorphism in the α2A‐adrenergic receptor gene (ADRA2A) promoter is associated with cortisol escape from dexamethasone and elevated glucose levels , 2002, Journal of internal medicine.

[10]  C. Mantzoros,et al.  Genetic variability at the leptin receptor (LEPR) locus is a determinant of plasma fibrinogen and C-reactive protein levels. , 2007, Atherosclerosis.

[11]  C. Bouchard,et al.  The Alpha2-Adrenergic Receptor Gene and Body Fat Content and Distribution: The HERITAGE Family Study , 2002 .

[12]  Christian Gieger,et al.  Genome-wide scan identifies CDH13 as a novel susceptibility locus contributing to blood pressure determination in two European populations , 2009, Human molecular genetics.

[13]  Ali G. Gharavi,et al.  Molecular Mechanisms of Human Hypertension , 2001, Cell.

[14]  C. Bouchard,et al.  The alpha 2-adrenergic receptor gene and body fat content and distribution: the HERITAGE Family Study. , 2002, Molecular medicine.

[15]  Hypertension in obesity and the leptin receptor gene locus. , 2000, The Journal of clinical endocrinology and metabolism.

[16]  [Bone mineral density and leptin receptor polymorphism Gln223Arg in Han women in Beijing]. , 2004, Zhonghua nei ke za zhi.

[17]  Mark I. McCarthy,et al.  Concept, Design and Implementation of a Cardiovascular Gene-Centric 50 K SNP Array for Large-Scale Genomic Association Studies , 2008, PloS one.

[18]  K. O’Shaughnessy.  The genetics of essential hypertension. , 2008, British journal of clinical pharmacology.

[19]  P. Donnelly,et al.  A new statistical method for haplotype reconstruction from population data. , 2001, American journal of human genetics.

[20]  Jurg Ott,et al.  Distribution and characterization of regulatory elements in the human genome. , 2002, Genome research.

[21]  Zhaohui S. Qin,et al.  A second generation human haplotype map of over 3.1 million SNPs , 2007, Nature.

[22]  Daniel Levy,et al.  Framingham Heart Study 100K Project: genome-wide associations for blood pressure and arterial stiffness , 2007, BMC Medical Genetics.

[23]  K. Okamoto,et al.  Development of a strain of spontaneously hypertensive rats. , 1963, Japanese circulation journal.

[24]  M Farrall,et al.  A rare variant of the leptin gene has large effects on blood pressure and carotid intima-medial thickness: a study of 1428 individuals in 248 families , 2005, Journal of Medical Genetics.

[25]  M. McCarthy,et al.  Genome-wide association studies for complex traits: consensus, uncertainty and challenges , 2008, Nature Reviews Genetics.

[26]  S. Harrap.  Hypertension: genes versus environment , 1994, The Lancet.

[27]  Harald Grallert,et al.  Genome Wide Association (GWA) Study for Early Onset Extreme Obesity Supports the Role of Fat Mass and Obesity Associated Gene (FTO) Variants , 2007, PloS one.

[28]  Pak Chung Sham,et al.  WHAP: haplotype-based association analysis , 2007, Bioinform..

[29]  Nilesh J Samani,et al.  Common Variants in Genes Underlying Monogenic Hypertension and Hypotension and Blood Pressure in the General Population , 2008, Hypertension.

[30]  C. Bouchard,et al.  Beta-2 adrenergic receptor variants are associated with subcutaneous fat accumulation in response to long-term overfeeding , 2001, International Journal of Obesity.

[31]  A. Cowley.  The genetic dissection of essential hypertension , 2006, Nature Reviews Genetics.

[32]  M. Stephens,et al.  Imputation-Based Analysis of Association Studies: Candidate Regions and Quantitative Traits , 2007, PLoS genetics.

[33]  Ross Ihaka,et al.  Gentleman R: R: A language for data analysis and graphics , 1996 .

[34]  Hongyu Zhao,et al.  Rare independent mutations in renal salt handling genes contribute to blood pressure variation , 2008, Nature Genetics.

[35]  Ki-Up Lee,et al.  Estrogen receptor alpha gene polymorphisms Pvu II and Xba I influence association between leptin receptor gene polymorphism (Gln223Arg) and bone mineral density in young men. , 2002, European journal of endocrinology.

[36]  Ying Wang,et al.  Genomewide association study of leprosy. , 2009, The New England journal of medicine.

[37]  Peter Donnelly,et al.  A comparison of bayesian methods for haplotype reconstruction from population genotype data. , 2003, American journal of human genetics.

[38]  J. Halaas,et al.  Leptin and the regulation of body weight in mammals , 1998, Nature.

[39]  Simon C. Potter,et al.  Genome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls , 2007, Nature.

[40]  R. Breyer,et al.  Prostaglandin E receptors and the kidney. , 2000, American journal of physiology. Renal physiology.

[41]  Mark Daly,et al.  Haploview: analysis and visualization of LD and haplotype maps , 2005, Bioinform..