Genome-wide association study identifies CAMKID variants involved in blood pressure response to losartan: the SOPHIA study.

BACKGROUND: Essential hypertension arises from the combined effect of genetic and environmental factors. A pharmacogenomics approach could help to identify additional molecular mechanisms involved in its pathogenesis. AIM: The aim of SOPHIA study was to identify genetic polymorphisms regulating blood pressure response to the angiotensin II receptor blocker, losartan, with a whole-genome approach. MATERIALS & METHODS: We performed a genome-wide association study on blood pressure response in 372 hypertensives treated with losartan and we looked for replication in two independent samples. RESULTS: We identified a peak of association in CAMK1D gene (rs10752271, effect size -5.5 ± 0.94 mmHg, p = 1.2 × 10(-8)). CAMK1D encodes a protein that belongs to the regulatory pathway involved in aldosterone synthesis. We tested the specificity of rs10752271 for losartan in hypertensives treated with hydrochlorothiazide and we validated it in silico in the GENRES cohort. CONCLUSION: Using a genome-wide approach, we identified the CAMK1D gene as a novel locus associated with blood pressure response to losartan. CAMK1D gene characterization may represent a useful tool to personalize the treatment of essential hypertension.

DEspR T/CATAAAA-box promoter variant decreases DEspR transcription and is associated with increased BP in Sardinian males.

Essential hypertension is highly prevalent in the elderly population, exceeding 70% in people older than 60 yr of age, and remains a leading risk factor for heart disease, stroke, and chronic renal disease. Elucidation of genetic determinants is critical but remains a challenge due to its complex, multifactorial pathogenesis. We investigated the role DEspR promoter variants, previously associated with male essential hypertension susceptibility, in blood pressure (BP) regulation. We detected a single nucleotide polymorphism within the DEspR 5'-regulatory region associated with increased BP in a male Sardinian cohort accounting for 11.0 mmHg of systolic BP (P<10(-15)) and 9.3 mmHg of diastolic BP (P<10(-15)). Sequence analysis of three normotensive subjects homozygous for the rs6535847 "normotension-associated T-allele" identified a canonical TATAAAA-box in contrast to a CATAAAA-motif in three hypertensive subjects homozygous for the rs6535847 "hypertension-associated C-allele." In vitro analysis detected decreased transcription activity with the CATAAAA-motif promoter-construct compared with the canonical TATAAAA-box promoter-construct. Although BP did not differ between DEspR+/- knockout male mice and wild-type littermates at 6 mo of age, radiotelemetric BP measurements in 18 mo old inbred DEspR+/- knockout male mice known to have decreased DEspR RNA and protein detected higher systolic, mean, and diastolic BPs in DEspR+/- mice compared with littermate wild-type controls (P<0.05). Our results demonstrate that promoter variants in DEspR associated with hypertension susceptibility and increased BP in Sardinian males affect transcription levels, which then affect BP in an age-dependent and male-specific manner. This finding is concordant with the late-onset and sex-specific characteristics of essential hypertension, thus reiterating the mandate for sex-specific analyses and treatment approaches for essential hypertension.

Haplotypes of the adrenergic system predict the blood pressure response to beta-blockers in women with essential hypertension.

AIMS: To analyze the association of haplotypes of the adrenergic system with essential hypertension and with the blood pressure response to beta-blockers. MATERIALS & METHODS: In 1112 never-treated essential hypertension patients and 203 normotensive controls, tightly linked SNPs of beta-adrenergic receptors (ADRB1 - Ser49Gly and Arg389Gly; ADRB2 - Cys19Arg, Gly16Arg and Gln27Glu) and the G-protein beta3-subunit (GNB3 - A3882C, G5249A and C825T) were genotyped. Association of haplotypes with essential hypertension and with the blood pressure response to atenolol 50 mg twice daily in a subgroup of essential hypertension patients (n = 340) was evaluated (Haploview 3.2). RESULTS: No SNPs or haplotypes were associated with essential hypertension. In females only, GNB3 SNPs and haplotypes were associated with the blood pressure response (p < 0.05). CONCLUSION: Our study confirmed the sex-specific association of GNB3 with the blood pressure response to atenolol with no substantial advantage of the analysis of haplotypes over SNPs.

Clinical variables, not RAAS polymorphisms, predict blood pressure response to ACE inhibitors in Sardinians.

AIM: No definite factors predict blood pressure response to angiotensin-converting enzyme-inhibitors. The aim of this study was to test the association of gene polymorphisms of the renin-angiotensin-aldosterone system with essential hypertension and anthropometric variables, intermediate phenotypes and gene polymorphisms with blood pressure after fosinopril in a genetically homogeneous cohort. METHODS: A total of 630 essential hypertension patients, not previously treated or out of antihypertensive treatment for at least 6 months versus 219 normotensives (genotype frequencies, chi(2)). A total of 191 patients were randomly assigned to fosinopril 20 mg/day. Samples for plasma renin activity and aldosterone, 24-h urinary sodium (flame photometry) were collected. Gene polymorphisms--angiotensin-converting enzyme (insertion/deletion), angiotensin II type 1-receptor (A1166C), aldosterone synthase (-344C/T) and angiotensinogen (-6A/G)--were analyzed by standard techniques. The association of anthropometric variables, intermediate phenotypes and gene polymorphisms with blood pressure after 4 weeks therapy was tested by univariate analysis and analysis of covariance model (Intercooled Stata SE 9.2). RESULTS: No genetic polymorphisms were associated with essential hypertension, blood pressure response and intermediate phenotypes (p > 0.05). Systolic blood pressure after therapy was associated with baseline systolic blood pressure, age and sex. CONCLUSIONS: Our results confirm the difficulty in dissecting both essential hypertension and pharmacogenomics when analyzing the effect of single genes in complex multifactorial traits.