Showing papers by "Marketa Sjögren published in 2011"

Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk

Abstract: Blood pressure is a heritable trait(1) influenced by several biological pathways and responsive to environmental stimuli. Over one billion people worldwide have hypertension (>= 140 mm Hg systolic blood pressure or >= 90 mm Hg diastolic blood pressure)(2). Even small increments in blood pressure are associated with an increased risk of cardiovascular events(3). This genome-wide association study of systolic and diastolic blood pressure, which used a multi-stage design in 200,000 individuals of European descent, identified sixteen novel loci: six of these loci contain genes previously known or suspected to regulate blood pressure (GUCY1A3-GUCY1B3, NPR3-C5orf23, ADM, FURIN-FES, GOSR2, GNAS-EDN3); the other ten provide new clues to blood pressure physiology. A genetic risk score based on 29 genome-wide significant variants was associated with hypertension, left ventricular wall thickness, stroke and coronary artery disease, but not kidney disease or kidney function. We also observed associations with blood pressure in East Asian, South Asian and African ancestry individuals. Our findings provide new insights into the genetics and biology of blood pressure, and suggest potential novel therapeutic pathways for cardiovascular disease prevention.

Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk

Abstract: Blood pressure (BP) is a heritable trait1 influenced by multiple biological pathways and is responsive to environmental stimuli. Over one billion people worldwide have hypertension (BP ≥140 mm Hg systolic [SBP] or ≥90 mm Hg diastolic [DBP])2. Even small increments in BP are associated with increased risk of cardiovascular events3. This genome-wide association study of SBP and DBP, which used a multi-stage design in 200,000 individuals of European descent, identified 16 novel loci: six of these loci contain genes previously known or suspected to regulate BP (GUCY1A3-GUCY1B3; NPR3-C5orf23; ADM; FURIN-FES; GOSR2; GNAS-EDN3); the other 10 provide new clues to BP physiology. A genetic risk score based on 29 genome-wide significant variants was associated with hypertension, left ventricular wall thickness, stroke, and coronary artery disease, but not kidney disease or kidney function. We also observed associations with BP in East Asian, South Asian, and African ancestry individuals. Our findings provide new insights into the genetics and biology of BP, and suggest novel potential therapeutic pathways for cardiovascular disease prevention. Genetic approaches have advanced the understanding of biological pathways underlying inter-individual variation in BP. For example, studies of rare Mendelian BP disorders have identified multiple defects in renal sodium handling pathways4. More recently two genomewide association studies (GWAS), each of >25,000 individuals of European-ancestry, identified 13 loci associated with SBP, DBP, and hypertension5,6. We now report results of a new meta-analysis of GWAS data that includes staged follow-up genotyping to identify additional BP loci. Primary analyses evaluated associations between 2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and SBP and DBP in 69,395 individuals of European ancestry from 29 studies (Supplementary Materials Sections 1–3, Supplementary Tables 1– 2). Following GWAS meta-analysis, we conducted a three-stage validation experiment that made efficient use of available genotyping resources, to follow up top signals in up to 133,661 additional individuals of European descent (Supplementary Fig. 1 and Supplementary Materials Section 4). Twenty-nine independent SNPs at 28 loci were significantly associated with SBP, DBP, or both in the meta-analysis combining discovery and follow up data (Fig. 1, Table 1, Supplementary Figs 2–3, Supplementary Tables 3–5). All 29 SNPs attained association P <5×10−9, an order of magnitude beyond the standard genome-wide significance level for a single stage experiment (Table 1). Sixteen of these 29 associations were novel (Table 1). Two associations were near the FURIN and GOSR2 genes; prior targeted analyses of variants in these genes suggested they Note added in proof: Since this manuscript was submitted, Kato et al published a BP GWAS in East Asians that identified a SNP highly correlated to the SNP we report at the NPR3-c5orf23 locus28. Author contributions Full author contributions and roles are listed in the Supplementary Materials Section 19. NIH Public Access Author Manuscript Nature. Author manuscript; available in PMC 2012 May 01. Published in final edited form as: Nature. ; 478(7367): 103–109. doi:10.1038/nature10405. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript may be BP loci7,8. At the CACNB2 locus we validated association for a previously reported6 SNP rs4373814 and detected a novel independent association for rs1813353 (pairwise r2 =0.015 in HapMap CEU). Of our 13 previously reported associations5,6, only the association at PLCD3 was not supported by the current results (Supplementary Table 4). Some of the associations are in or near genes involved in pathways known to influence BP (NPR3, GUCY1A3-GUCY1B3, ADM, GNAS-EDN3, NPPA-NPPB, and CYP17A1; Supplementary Fig. 4). Twenty-two of the 28 loci did not contain genes that were a priori strong biological candidates. As expected from prior BP GWAS results, the effects of the novel variants on SBP and DBP were small (Fig. 1 and Table 1). For all variants, the observed directions of effects were concordant for SBP, DBP, and hypertension (Fig. 1, Table 1, Supplementary Fig. 3). Among the genes at the genome-wide significant loci, only CYP17A1, previously implicated in Mendelian congenital adrenal hyperplasia and hypertension, is known to harbour rare variants that have large effects on BP9. We performed several analyses to identify potential causal alleles and mechanisms. First, we looked up the 29 genome-wide significant index SNPs and their close proxies (r2>0.8) among cis-acting expression SNP (eSNP) results from multiple tissues (Supplementary Materials Section 5). For 13/29 index SNPs, we found association between nearby eSNP variants and expression level of at least one gene transcript (10−4 > p > 10−51, Supplementary Table 6). In 5 cases, the index BP SNP and the best eSNP from a genomewide survey were identical, highlighting potential mediators of the SNP-BP associations. Second, because changes in protein sequence are strong a priori candidates to be functional, we sought non-synonymous coding SNPs that were in high LD (r2 >0.8) with the 29 index SNPs. We identified such SNPsat 8 loci (Table 1, Supplementary Materials Section 6, Supplementary Table 7). In addition we performed analyses testing for differences in genetic effect according to body mass index (BMI) or sex, and analyses of copy number variants, pathway enrichment, and metabolomic data, but we did not find any statistically significant results (Supplementary Materials Sections 7–9, Supplementary Tables 8–10). We evaluated whether the BP variants we identified in Europeans were associated with BP in individuals of East Asian (N=29,719), South Asian (N=23,977), and African (N=19,775) ancestries (Table 1, Supplementary Tables 11–13). We found significant associations in individuals of East Asian ancestry for SNPs at 9 loci and in individuals of South Asian ancestry for SNPs at 6 loci; some have been reported previously (Supplementary Tables 12 and 15). The lack of significant association for individual SNPs may reflect small sample sizes, differences in allele frequencies or LD patterns, imprecise imputation for some ancestries using existing reference samples, or a genuinely different underlying genetic architecture. Because of limited power to detect effects of individual variants in the smaller non-European samples, we created genetic risk scores for SBP and DBP incorporating all 29 BP variants weighted according to effect sizes observed in the European samples. In each non-European ancestry group, risk scores were strongly associated with SBP (P=1.1×10−40 in East Asian, P=2.9×10−13 in South Asian, P=9.8×10−4 in African ancestry individuals) and DBP (P=2.9×10−48, P=9.5×10−15, and P=5.3×10−5, respectively; Supplementary Table 13). We also created a genetic risk score to assess association of the variants in aggregate with hypertension and with clinical measures of hypertensive complications including left ventricular mass, left ventricular wall thickness, incident heart failure, incident and prevalent stroke, prevalent coronary artery disease (CAD), kidney disease, and measures of kidney function, using results from other GWAS consortia (Table 2, Supplementary Materials Sections 10–11, Supplementary Table 14). The risk score was weighted using the average of Page 2 Nature. Author manuscript; available in PMC 2012 May 01. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript SBP and DBP effects for the 29 SNPs. In an independent sample of 23,294 women10, an increase of 1 standard deviation in the genetic risk score was associated with a 21% increase in the odds of hypertension (95% CI 19%–28%; Table 2, Supplementary Table 14). Among individuals in the top decile of the risk score, the prevalence of hypertension was 29% compared with 16% in the bottom decile (odds ratio 2.09, 95% CI 1.86–2.36). Similar results were observed in an independent hypertension case-control sample (Table 2). In our study, individuals in the top compared to bottom quintiles of genetic risk score differed by 4.6 mm Hg SBP and 3.0 mm Hg DBP, differences that approach population-averaged BP treatment effects for a single antihypertensive agent11. Epidemiologic data have shown that differences in SBP and DBP of this magnitude, across the population range of BP, are associated with an increase in cardiovascular disease risk3. Consistent with this and in line with findings from randomized trials of BP-lowering medication in hypertensive patients12,13, the genetic risk score was positively associated with left ventricular wall thickness (P=6.0×10−6), occurrence of stroke (P=3.3×10−5) and CAD (P=8.1×10−29). The same genetic risk score was not, however, significantly associated with chronic kidney disease or measures of kidney function, even though these renal outcomes were available in a similar sample size as for the other outcomes (Table 2). The absence of association with kidney phenotypes could be explained by a weaker causal relation of BP with kidney phenotypes than with CAD and stroke. This finding is consistent with the mismatch between observational data that show a positive association of BP with kidney disease, and clinical trial data that show inconsistent evidence of benefit of BP lowering on kidney disease prevention in patients with hypertension14. Thus, several lines of evidence converge to suggest that BP elevation may in part be a consequence rather than a cause of sub-clinical kidney disease. Our discovery meta-analysis (Supplementary Fig. 2) suggests an excess of modestly significant (10−5

A variant upstream of the CDH13 adiponectin receptor gene and metabolic syndrome in Swedes.

Abstract: Metabolic syndrome (MetS) constitutes a worldwide epidemic burst accounting for billions of cardiovascular disease events and deaths. The genetic basis of MetS is largely unknown. The rs11646213 T → A polymorphism maps at 16q23.3 upstream of the CDH13 gene codifying for cadherin-13 (also known as T-cadherin or H-cadherin), which is considered a vascular adiponectin receptor. This and other single-nucleotide polymorphisms have been associated with hypertension and adiponectin level in separate studies. The aim of the present study was to evaluate the effect of the CDH13 rs11646213 T → A polymorphism on individual components of MetS and on MetS. The polymorphism was genotyped in the cardiovascular cohort of the Malmo Diet and Cancer Study (n = 4,942) and successively in the Malmo Preventive Project (n = 17,675) cohort at baseline and after an average of 23 years of follow-up (reinvestigation). Four different definitions of MetS were applied to these cohorts. In the cardiovascular arm, CDH13 rs11646213 AA homozygotic women showed a trend toward higher triglycerides and lower high-density lipoprotein cholesterol and presented a higher MetS score (composite sum of MetS phenotypes). MetS (Adult Treatment Panel III definition) was more prevalent in AA homozygotic women compared to T-carriers, a result confirmed in the Malmo Preventive Project cohort at baseline and at reinvestigation with an increased risk from 19% to 45% in AA homozygotic women. In conclusion, the CDH13 rs11646213 T > A polymorphism was consistently associated with MetS in Swedish women recruited in 2 large cohorts. In light of the role of cadherin-13 as a vascular receptor for adiponectin, our study supports the genetic basis for the role of adiponectin in MetS pathogenesis.

Serine/threonine kinase 39 is a candidate gene for primary hypertension especially in women: results from two cohort studies in Swedes.

Abstract: BACKGROUND: As recently pinpointed by a genome-wide association study the serine/threonine kinase 39 (STK39) is a candidate gene for hypertension. This kinase is strongly implicated in sodium reabsorption by the kidney through its modulating effect on furosemide-sensitive and thiazide-sensitive channels. The aim of our study was to test the effects of the STK39 rs35929607A>G polymorphism on blood pressure (BP) levels and the prevalence and incidence of hypertension in middle-aged Swedes participating in two urban-based surveys in Malmo (Sweden). METHODS: The rs35929607A>G polymorphism was genotyped in 5634 participants included in the cardiovascular cohort of the 'Malmo Diet and Cancer-cardiovascular arm' (MDC-CVA) study and successively in 17 894 participants of the 'Malmo Preventive Project' (MPP) both at baseline and at reinvestigation after a mean of 23 years. The effect of the same single nucleotide polymorphism on salt sensitivity was tested in 39 participants of the Salt Reduction to Avoid Hypertension study. RESULTS: Both before and after adjustment for covariates, the functional rs35929607A>G polymorphism was associated with higher SBP and DBP values in the MDC-CVA, but not in the MPP. In both surveys, the polymorphism was associated with hypertension prevalence; after adjustment using the autosomal-dominant model, the odds ratio for hypertension ranged between 1.077 (MPP at baseline) and 1.151 (MDC-CVA) with P-value less than 0.05. After stratification for sex, the results remained statistically significant in women, but not in men. Carriers of the G-allele displayed an increase in salt sensitivity. CONCLUSION: Our results from two large cohort studies support previous evidence about the association of the STK39 rs35929607A>G variant with hypertension, especially in women. If further confirmed in successive studies, owing to its pivotal role in sodium reabsorption at the renal tubule level, STK39 might prove to be a suitable target for antihypertensive therapy. The greater effect of the STK39 rs35929607A>G polymorphism in women with respect to men deserves further investigation. (Less)

Genetic Variant on Chromosome 12p13 Does Not Show Association to Ischemic Stroke in 3 Swedish Case-Control Studies

Abstract: Background and Purpose—In a genome-wide association study and subsequent case-control studies, the single-nucleotide polymorphism rs12425791 on chromosome 12p13 was reported to be associated with ischemic stroke, but this could not be validated in a recent well-powered study. We therefore investigated whether an association between ischemic stroke and rs12425791 could be detected in 3 different case-control studies from the southwest of Sweden. Methods—We examined 3606 patients with ischemic stroke and 2528 controls from 3 independent case-controls studies. Results—No significant association between ischemic stroke and the single-nucleotide polymorphism rs12425791 was detected in any of the 3 case-control samples or in the samples combined. The odds ratio for ischemic stroke for the minor allele in the combined sample was 1.02 (95% CI, 0.93 to 1.13). Conclusions—The single-nucleotide polymorphism rs12425791 does not confer a substantial risk for ischemic stroke in our population. Our results support a rec...