Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence phenotype. Genome-wide association (GWA) studies have identified >600 variants associated with human traits1, but these typically explain small fractions of phenotypic variation, raising questions about the utility of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait2,3. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P=0.016), and that underlie skeletal growth defects (P<0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants, and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented amongst variants that alter amino acid structure of proteins and expression levels of nearby genes. Our data explain ∼10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to ∼16% of phenotypic variation (∼20% of heritable variation). Although additional approaches are needed to fully dissect the genetic architecture of polygenic human traits, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.

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Our findings show that the ANP/NPRA system significantly contributes to ventricular remodeling in human essential hypertension.

Abstract-Essential hypertension is a multifactorial disorder and is the main risk factor for renal and cardiovascular complications. The research on the genetics of hypertension has been frustrated by the small predictive value of the discovered genetic variants. The HYPERGENES Project investigated associations between genetic variants and essential hypertension pursuing a 2-stage study by recruiting cases and controls from extensively characterized cohorts recruited over many years ). A meta-analysis, using other in silico/de novo genotyping data for a total of 21 714 subjects, resulted in an overall odds ratio of 1.34 (95% CI: 1.25-1.44; Pϭ1.032 ⅐ 10 Ϫ14). The quantitative analysis on a population-based sample revealed an effect size of 1.91 (95% CI: 0.16 -3.66) for systolic and 1.40 (95% CI: 0.25-2.55) for diastolic blood pressure. We identified in silico a potential binding site for ETS transcription factors directly next to rs3918226, suggesting a potential modulation of endothelial NO synthase expression. Biological evidence links endothelial NO synthase with hypertension, because it is a critical mediator of cardiovascular homeostasis and blood pressure control via vascular tone regulation. This finding supports the hypothesis that there may be a causal genetic variation at this locus. (Hypertension. 2012;59:248-255.) • Online Data Supplement Key Words: genetic epidemiology Ⅲ risk factors Ⅲ genetics association studies Ⅲ NO Ⅲ essential hypertension E ssential hypertension (EH) is a clinical condition affecting a large proportion (25% to 30%) of the adult population and is a major risk factor for cardiovascular and renal diseases. 1,2 It is a complex trait influenced by multiple susceptibility genes, environmental, and lifestyle factors and their interactions. 3 In the last years, huge efforts have been performed in recruiting and genotyping tens of thousands of individuals and meta-analyzing dozens of cross-sectional, population-based studies. In spite of this, the research on the genetics of EH has been frustrated by the small predictive value of the discovered genetic variants and by the fact that these variants explain a small proportion of the phenotypic variation. 4 -13 EH is a late-onset disease and, therefore, the small discovered effect sizes could in part be because of the effect of misclassification, sample selection bias, and inappropriate phenotyping of cases and controls. 9,14,15 The selection of cases and controls may have important effects on the results, because misclassification bias can lead to loss of power. For common traits, such as EH, this bias can be remedied by defining more stringent selection criteria, by recruiting hypernormal controls and adopting a more stringent case definition. 14,15 The HYPERGENES Project pursued a 2-stage study to investigate novel genetic determinants of EH. Cases and controls were recruited from extensively characterized cohorts over many years in different European regions using standardized clinical ascertainment. Particular care was devoted to c...

Previous studies on genetic rat hypertension have shown that polymorphism within the alpha-adducin gene may regulate blood pressure. Adducin is a cytoskeletal protein that may be involved in cellular signal transduction and interacts with other membrane-skeleton proteins that affect ion transport across the cell membrane. There is a high homology between rat and human adducin and pathophysiological similarities between the Milan hypertensive rat strain and a subgroup of patients with essential hypertension. Thus, we designed a case-control study to test the possible association between the alpha-adducin locus and hypertension. One hundred ninety primary hypertensive patients were compared with 126 control subjects. All subjects were white and unrelated. Four multiallelic markers surrounding the alpha-adducin locus located in 4p16.3 were selected: D4S125 and D4S95 mapping at 680 and 20 kb centromeric, and D4S43 and D4S228/E24 mapping at 660 and 2500 kb telomeric. Alleles for each marker were pooled into groups. Comparisons between control subjects and hypertensive patients were carried out by testing the allele-disease association relative to the marker genotype. The maximal association occurred for D4S95 (chi 2(1) 13.33), which maps closest to alpha-adducin. These data suggest that a polymorphism within the alpha-adducin gene may affect blood pressure in humans.

Abstract.Fibronectin isoforms are generated by the alternative splicing of a primary transcript derived from a single gene. In rat at least three regions of the molecule are involved: EIIIA, EIIIB, and V. This study investigated the splicing patterns of these regions during development and aging, by means of ribonuclease protection analysis. Between fetal and adult rat, the extent of inclusion of the EIIIA and/or EIIIB region in fibronectin mRNA varied according to the type of tissue analyzed; but the inclusion of the V region, and in particular the V25 alternative variant, was significantly higher in all fetal than in adult tissues. These data suggest a crucial role of the V25 variant, possibly related to its interaction with the c~4~1 integrin receptor during development. On the other hand, during aging, the only significant change observed in the splicing pattern was a decrease in the EIIIA variant in brain. The high inclusion levels of the EIIIA and EIIIB regions in young adult brain suggest that these segments may play an important role in differentiated brain tissue. The decreasing levels of inclusion of the EIIIA segment in brain fibronectin mRNA during aging may be an age-related marker with functional consequences. CELL-to-cell and cell-to-substrate interactions play a fundamental role in cell behavior, division, and differentiation. Among the extracellular components involved in these events, fibronectin (FN) ~ is probably one of the most important and widely distributed. Fibronectin is a dimeric high molecular weight glycoprotein found in blood, lymph, and tissue fluids, as well as in association with basement membranes, connective tissue matrices and the extracellular matrix of many cells (23, 37).The primary structure of FN has been described at both protein (human and bovine FN) and cDNA (chicken, rat, and human FN) levels (4, 13-15, 21, 26, 32, 33, 40, 41, 43, 45). The FN molecule is composed of three different kinds of repeated sequence, known as types I, II and III with a characteristic modular structure (21,33,40,41,43). These repeats are assembled into a series of structural domains, each having a distinct binding activity toward collagen, sulfated glycosaminoglycans, fibrin, and the cell surface receptors collectively termed integrins (19,36,49).FN molecules are a mixture of several protein types that differ both in their primary structure, and in their posttranslational modifications. All of the sequence variations are produced by the alternative processing of a common mRNA precursor (pre-mRNA) transcribed from a single gene and 1. Abbreviation used in this paper: FN, fibronectin. differentially spliced in the various cell types (1,18,30,40,41,45,50).Three sites of alternative splicing have so far been described: ED-A, ED-B, and IIICS in human FN and the corresponding sites (EIIIA, EIIIB, and V) in rat FN. EIIIA and EIIIB share a common gene structure and, in both cases, alternative splicing leads to the insertion of an additional exon coding for a type III homology domain. The V region in ...

Abstract-The kidney plays an important role in salt and blood pressure (BP) homeostasis. In previous studies, variants in the genes for ␣-adducin (ADD1), WNK1, and NEDD4L, which all regulate renal sodium absorption, have been associated with increased BP. However, findings have been inconsistent. We tested whether this is because of physiological interactions between the effects of variants in these genes. We assessed the single and combined effects of the ADD1 (Gly460Trp), WNK1 (rs880054 A/G), and NEDD4L (rs4149601 G/A) polymorphisms on renal and BP response to an acute Na load (nϭ344 subjects), BP decrease after 1 month of treatment with 12.5 mg of hydrochlorothiazide (nϭ193), and ambulatory 24-hour BP (nϭ690). Individually, the variants showed modest effects on some of the studied phenotypes. We found the ADD1 Trp allele to be permissive for the effects of variants of the other genes. In combination, the same variants (ADD1 Trp/WNK1 GG/Nedd4L GAϩAA) showed a consistent effect on renal Na handling (Pϭ0.009) and acute BP response to a saline infusion (Pϭ0.021), BP lowering after thiazide treatment (Pϭ0.008), and nocturnal systolic BP (Pϭ0.044). Physiological interaction between the ADD1 and WNK1-NEDD4L pathways influences the effects of variants in these genes on sodium-related BP regulation. Relatively common alleles in the ADD1, WNK1, and NEDD4L genes when present in combination may have significant effects on renal sodium handling, BP, and antihypertensive response to thiazides. (Hypertension. 2008;52:366-372.)Key Words: hypertension Ⅲ genetic Ⅲ sodium transport Ⅲ kidney Ⅲ blood pressure Ⅲ tubular Ⅲ renal R egulation of body sodium and blood pressure (BP) is achieved through the interaction of several mechanisms, including sodium (Na) transport at the basolateral and luminal tubular cell membranes along specific nephron segments. Moreover, physical, nervous, and hormonal mechanisms modulate this constitutive capacity of tubular cells to transport Na according to the body's needs. 1 In fact, virtually all mendelian disorders leading to hypertension are caused by gene variants affecting salt reabsorption. 2 A comprehensive approach to the genetics of the regulation of body Na and BP should take into account the interactions among the underlying variety of gene polymorphisms. At present, this approach is not feasible globally for the prohibitive size of the cohort required. However, a contribution along this line may be provided by focusing on genes affecting luminal (WNK1 and NEDD4L) and basolateral transport of Na (Adducin) in patients whose BP is changed by maneuvers affecting body Na.These genes have been chosen for the following reasons: a missense mutation in the ␣-adducin (ADD1 Gly/Trp) gene has been shown to affect the function of the protein with the Trp allele resulting in greater renal Na-K pump activity in nephron segments proximal to the macula densa. 3,4 Results of association studies of the Trp allele with BP are conflicting when this allele is considered alone, 5 but they are much more consisten...

The importance of excess salt intake in the pathogenesis of hypertension is widely recognized. Blood pressure is controlled primarily by salt and water balance because of the infinite gain property of the kidney to rapidly eliminate excess fluid and salt. Up to fifty percent of patients with essential hypertension are salt-sensitive, as manifested by a rise in blood pressure with salt loading. We conducted a two-stage genetic analysis in hypertensive patients very accurately phenotyped for their salt-sensitivity. All newly discovered never treated before, essential hypertensives underwent an acute salt load to monitor the simultaneous changes in blood pressure and renal sodium excretion. The first stage consisted in an association analysis of genotyping data derived from genome-wide array on 329 subjects. Principal Component Analysis demonstrated that this population was homogenous. Among the strongest results, we detected a cluster of SNPs located in the first introns of PRKG1 gene (rs7897633, p = 2.34E-05) associated with variation in diastolic blood pressure after acute salt load. We further focused on two genetic loci, SLC24A3 and SLC8A1 (plasma membrane sodium/calcium exchange proteins, NCKX3 and NCX1, respectively) with a functional relationship with the previous gene and associated to variations in systolic blood pressure (the imputed rs3790261, p = 4.55E-06; and rs434082, p = 4.7E-03). In stage 2, we characterized 159 more patients for the SNPs in PRKG1, SLC24A3 and SLC8A1. Combined analysis showed an epistatic interaction of SNPs in SLC24A3 and SLC8A1 on the pressure-natriuresis (p interaction = 1.55E-04, p model = 3.35E-05), supporting their pathophysiological link in cellular calcium homeostasis. In conclusions, these findings point to a clear association between body sodium-blood pressure relations and molecules modulating the contractile state of vascular cells through an increase in cytoplasmic calcium concentration.