Schut, A.F.C.

Heritability of blood pressure traits and the genetic contribution to blood pressure variance explained by four blood-pressure-related genes (Article)

2007-03-01T00:00:00Z

OBJECTIVE: To study the heritability of four blood pressure traits and the proportion of variance explained by four blood-pressure-related genes. METHODS: All participants are members of an extended pedigree from a Dutch genetically isolated population. Heritability and genetic correlations of systolic blood pressure, diastolic blood pressure, mean arterial pressure and pulse pressure were assessed using a variance components approach (SOLAR). Polymorphisms of the α-adducin (ADD1), angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R) and G protein β3 (GNB3) genes were typed. RESULTS: Heritability estimates were significant for all four blood pressure traits, ranging between 0.24 and 0.37. Genetic correlations between systolic blood pressure, diastolic blood pressure and mean arterial pressure were high (0.93-0.98), and those between pulse pressure and diastolic blood pressure were low (0.05). The ADD1 polymorphism explained 0.3% of the variance of pulse pressure (P = 0.07), and the polymorphism of GNB3 explained 0.4% of the variance of systolic blood pressure (P = 0.02), 0.2% of mean arterial pressure (P = 0.05) and 0.3% of pulse pressure (P = 0.06). CONCLUSION: Genetic factors contribute to a substantial proportion of blood pressure variance. In this study, the effect of polymorphisms of ADD1, AGT, AT1R and GNB3 explained a very small proportion of the heritability of blood pressure traits. As new genes associated with blood pressure are localized in the future, their effect on blood pressure variance should be calculated.

Heritabilities, apolipoprotein E, and effects of inbreeding on plasma lipids in a genetically isolated population: The Erasmus Rucphen family study (Article)

2007-02-01T00:00:00Z

Despite considerable progress in unravelling the genetic basis of dyslipidemias, most findings are based on families with extreme phenotypes. We studied lipid levels in an extended pedigree ascertained irrespective of phenotype from the population of a recent genetic isolate in the Netherlands. Heritabilities of plasma lipid measures were examined; this analysis also included estimates of the proportion of variance attributable to ApoE genotype. The association between inbreeding and lipids was also considered, as a substantial fraction of the population had known inbreeding. A total of 868 individuals from this pedigree, containing more than 60,000 people over 15 generations, were investigated in this study. Laboratory analysis of these subjects included the determination of fasting plasma lipids. ApoE ε2/3/4 status was ascertained using TaqMan assays. Heritabilities for plasma lipids were estimated with adjustments for multiple covariates using SOLAR. Heritabilities for total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), triglycerides (TG), TC/HDL ratio, and TG/HDL ratio were found to be 0.35, 0.56, 0.30, 0.24, 0.49, and 0.39, respectively. The addition of ApoE genotype in the model significantly decreased these estimates (Δh2= -0.030, -0.004, -0.054, and -0.006 for TC, HDL, LDL, and TG). In a further analysis, TC and LDL were positively associated with the extent of inbreeding (ptrend= 0.02 and ptrend= 0.05, respectively). These data provide estimates of lipid heritability unbiased due to selection and suggest that this population represents a good opportunity to localize novel genes influencing plasma lipid levels.

A promoter polymorphism of the insulin-like growth factor-I gene is associated with left ventricular hypertrophy (Article)

2005-01-01T00:00:00Z

Angiotensin converting enzyme gene polymorphism and cardiovascular morbidity and mortality: the Rotterdam Study. (Article)

2005-01-01T00:00:00Z

BACKGROUND: Findings on the association between the insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene and cardiovascular morbidity and mortality have been inconsistent. Considering the possible interaction between this polymorphism and smoking, we evaluated the association between ACE I/D polymorphism and myocardial infarction (MI), mortality due to coronary heart disease (CHD), and cardiovascular disease (CVD). METHODS: The study was performed within the Rotterdam Study, a population based cohort study. The ACE I/D polymorphism was determined for 6714 participants and smoking status recorded at baseline. Fatal and non-fatal MIs and mortality events were regularly recorded. Cox proportional hazard analysis was performed separately for current smokers and non-smokers. We used age as the follow up time, presenting age specific survivals. RESULTS: During follow up, 248 MIs and 301 and 482 deaths, respectively, due to CHD and CVD occurred. There were no significant differences between the genotypes as regards MI incidence. Among smokers, there was an increased risk of CHD and CVD mortality in carriers of the DD genotype compared to the II genotype, which diminished at later ages (p<0.01 for gene-age interaction). Subgroup analysis in a younger and older group (based on the median age of 68.2 years) showed a significantly increased risk of CVD mortality in the younger group (hazard ratio = 5.19; 95% confidence interval: 1.15 to 23.42). CONCLUSIONS: This study showed that the ACE I/D polymorphism is not a strong risk factor for MI but its interaction with smoking might play a role in cardiovascular mortality especially at younger ages.

Angiotensin converting enzyme insertion/deletion polymorphism and the risk of heart failure in hypertensive subjects. (Article)

2004-12-01T00:00:00Z

AIMS: Cardiac angiotensin-I converting enzyme (ACE) activity is influenced by the ACE I/D polymorphism. Evidence suggests that the DD-genotype may be a risk factor for cardiac hypertrophy and heart failure, especially in hypertensive subjects. We assessed the relation between the ACE I/D polymorphism and the risk of incident heart failure in normotensive and hypertensive subjects. METHODS AND RESULTS: We investigated 4264 normotensive and 2174 hypertensive participants of the Rotterdam Study, a population based prospective cohort study. All subjects were available for follow-up from 1990 until 2000. Incidence rates (IR) of heart failure in normotensive subjects were the same over all genotype strata (10 per 1000 person-years). In hypertensive subjects, the IR increased with the number of D-alleles present (II: IR=13, ID: IR=18 and DD: IR=20 per 1000 person-years). Hypertensive subjects carrying the II-genotype did not have an increased risk of heart failure compared to normotensive II subjects. However, hypertensive subjects carrying one or two copies of the D-allele did have a significantly increased risk of heart failure (ID: RR: 1.4 (1.1-1.9) and DD: RR: 1.5 (1.2-2.1)). CONCLUSION: Our findings suggest that the ACE I/D polymorphism may play a modifying role in the development of heart failure in hypertensive subjects.

In Search of Cardiovascular Risk Genes (Doctoral Thesis)

2004-09-29T00:00:00Z

Hypertension, or elevated arterial blood pressure is a substantial public health problem, affecting about 25 % of the adult population. This disorder is a major risk factor for common causes of morbidity and mortality including stroke, myocardial infarction, heart failure, and end-stage renal disease. Despite the morbid consequences of hypertension, its pathogenesis remains to be fully elucidated. Difficulties in defining the causes of hypertension from physiological studies alone have motivated studies to search for genetic factors in the etiology of hypertension. Identification of genes influencing blood pressure variation may confer more insight into the physiological mechanisms underlying blood pressure variation and reveal pathways and targets for therapeutical intervention. In recent years, several genes responsible for rare Mendelian forms of hypertension have been identified.

A study of gene-environment interaction on the gene for angiotensin converting enzyme: a combined functional and population based approach (Article)

2004-01-01T00:00:00Z

INTRODUCTION: Studies on the role of the insertion/deletion (I/D) polymorphism of the gene coding for angiotensin converting enzyme (ACE) in atherosclerosis have been inconsistent. In a meta-analysis, we recently showed that this relationship is stronger in high risk populations. In this paper, we used a combined functional and population based approach to investigate the gene-environment interaction of the ACE I/D polymorphism in relation to carotid artery wall thickness. METHODS: The study was part of the Rotterdam Study, a prospective population based cohort study. In 5321 subjects, IMT was measured in the carotid arteries by ultrasonography and ACE genotype was determined by size analysis of polymerase chain reaction products. RESULTS: In multiple regression analysis, I/D polymorphism and smoking were the main determinants for plasma ACE activity (r(2) = 0.28). There was a positive association between the D allele of the I/D polymorphism and carotid artery thickness among current smokers (p = 0.03). Subjects carrying only one of the risk factors (smoking or the D allele) did not show significant differences in IMT compared with the non-/former smokers group carrying two II alleles, while carriers of both risk factors had significant higher IMT. The association was not present in non-/former smokers. DISCUSSION: The results provide further evidence that genetic and environmental factors interact in the formation of the arterial lesions. This study shows that large population based studies can be extremely helpful in unravelling the genetic origin of complex diseases such as atherosclerosis.

Polymorphism in the promoter region of the insulin-like growth factor I gene is related to carotid intima-media thickness and aortic pulse wave velocity in subjects with hypertension. (Article)

2003-07-01T00:00:00Z

BACKGROUND AND PURPOSE: Low circulating levels of insulin-like growth factor I (IGF-I) have been associated with an increased risk for atherosclerosis. Absence of the 192-bp (wild-type) allele in the promoter region of the IGF-I gene has been associated with low circulating IGF-I levels. We examined the role of this polymorphism in relation to blood pressure and 2 early markers of atherosclerosis: carotid intima-media thickness (IMT) and aortic pulse wave velocity (PWV). METHODS: A total of 5132 subjects of the Rotterdam Study, aged 55 to 75 years, were included in this study. In 3769 subjects who did not use blood pressure-lowering medication, the association between the IGF-I polymorphism and blood pressure was examined. In the total population, and in 3484 normotensive subjects, 1648 hypertensive and 462 untreated hypertensive subjects, the association between this polymorphism and IMT and PWV was examined. RESULTS: Mean systolic and diastolic blood pressure did not differ between genotypes. In hypertensive subjects IMT was significantly increased in noncarriers of the 192-bp allele (0.83 mm) compared with heterozygous or homozygous carriers (0.80 mm) (P=0.04). PWV was also significantly higher in hypertensive subjects who were noncarriers of the 192-bp allele (14.3 m/s) compared with heterozygous (14.1 m/s) or homozygous carriers (13.7 m/s) (P=0.02). Findings were more pronounced in hypertensive subjects without medication use. In normotensive subjects, no association between this polymorphism, IMT, and PWV was observed. CONCLUSIONS: Our study suggests that hypertensive subjects who have low IGF-I levels because of a genetic polymorphism in the IGF-I gene are at increased risk of developing atherosclerosis.