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Biomedical subjects

Eric Boerwinkle

Publications and source records attributed to Eric Boerwinkle.

At least 73 records · Page 4Linked to original sources
PubMed2005

Plasma MCP-1 level and risk for peripheral arterial disease and incident coronary heart disease: Atherosclerosis Risk in Communities study.

Monocyte chemoattractant protein-1 (MCP-1), which mediates the recruitment of monocytes, has been suggested to play a role in atherosclerosis. Because the correlation between circulating MCP-1 and cardiovascular risk has not been thoroughly investigated, we determined the relationship between MCP-1 level and peripheral arterial disease (PAD) or coronary heart disease (CHD). In the Atherosclerosis Risk in Communities (ARIC) study, 209 cases with lower extremity PAD and 412 cases with incident CHD were compared with 733 and 709 subjects without PAD and CHD, respectively. Mean plasma MCP-1 levels were significantly higher in PAD cases (468.7 versus 416.5 pg/mL in non-cases). MCP-1 levels correlated significantly with other inflammatory markers in comparison subjects. Logistic regression analyses showed a significant association of MCP-1 with PAD, independent of traditional CHD risk factors, with an odds ratio of 2.14 (95% CI, 1.28-3.60) for the highest MCP-1 tertile compared with the lowest. Incident CHD risk increased significantly per 1 standard deviation (S.D.) difference in MCP-1 level independent of other cardiovascular risk factors, including inflammatory markers. These data show that MCP-1 is associated with atherosclerotic disease in two vascular beds and suggest that MCP-1 may be a novel target for atherosclerosis therapy.

Atherosclerosis↗
PubMed2005

Autosomal genome scan for loci linked to blood pressure levels and trends since childhood: the Bogalusa Heart Study.

Genetic loci influencing the long-term levels and trends of blood pressure over time were investigated using 775 white siblings, ages 13 to 43 years, enrolled in the Bogalusa Heart Study, and 357 microsatellite markers on the 22 autosomal chromosomes. Subjects had been examined serially 2 to 12 times with 4365 serial observations over an average of 22 years from childhood to adulthood. Total and incremental area under the curve was calculated based on a cubic growth curve and used as long-term levels and trends, respectively. After adjusting for age, sex, and body mass index, heritability estimates of total area were 0.66 for systolic and 0.68 for diastolic blood pressure. Heritability of incremental area was 0.38 for systolic and 0.46 for diastolic blood pressure. Significant linkage to the total area of diastolic blood pressure (peak logarithm of odds [LOD]=3.9 at 73 cM) was observed on chromosome 2, with a region spanning from 44 cM to 103 cM showing supporting linkage evidence of LOD >3.0. In addition, suggestive linkage for total area of systolic (LOD=1.6 at 182 cM) and diastolic blood pressure (LOD=2.0 at 36 cM) on chromosome 4 and diastolic blood pressure incremental area (LOD=2.2 at 28 cM) on chromosome 18 was noted. Several hypertension candidate genes such as alpha-adducin, beta-adducin, sodium bicarbonate co-transporter, and G protein-coupled receptor kinase 4 are located in these regions. Linkage evidence found in this community-based study indicates that regions on these chromosomes harbor genetic loci that affect the propensity for development of hypertension from childhood.

Adolescent↗
PubMed2005

Combined genealogical, mapping, and expression approaches to identify spontaneously hypertensive rat hypertension candidate genes.

Allelic expression in genes has become recognized as a heritable trait by which phenotypes are generated. We have examined gene expression in the rat kidney using genome-wide microarray technology (Affymetrix). Gene expression was determined across 4 rat strains, 3 hypertensive spontaneously hypertensive rat (SHR) substrains (SHR-A3, SHR-B2, and SHR-C), and a normotensive strain (Wistar-Kyoto [WKY]). Expression measurements were made in multiple animals from all strains at 4 time points (4 weeks, 8 weeks, 12 weeks, and 18 weeks of age), covering the prehypertensive period in SHR (4 weeks), and the period of rapidly rising blood pressure (8 and 12 weeks) and of sustained hypertension (18 weeks). Regression analysis revealed a close relationship across all strains during the first 3 time points, after which SHR-A3 became a substantial outlier. SHR-B2 and SHR-C demonstrated a very close relationship in gene expression at all times but also showed increased differences compared with the other strains at 18 weeks of age. We identified genes that were consistently different in expression, comparing all SHR substrains at each time point with WKY. The resulting list of genes was compared with blood pressure quantitative trait loci reported for SHR to refine a number of genes consistently differentially expressed between SHR substrains and WKY, persistently differentially expressed across multiple time points, and located in SHR blood pressure-determinative regions of the genome. Genealogical relationships and SHR substrain intercrosses suggest that genes responsible for heritable hypertension in SHR are shared across SHR substrains. The present approach identifies a number of genes that may influence blood pressure in SHR by virtue of allelic effects on gene expression.

Animals↗
PubMed2005

Genomic susceptibility loci for brain atrophy in hypertensive sibships from the GENOA study.

We measured 366 microsatellite markers genome-wide to search for loci contributing to subcortical white matter ischemic damage (leukoariosis) and brain atrophy in 488 non-Hispanic white subjects (193 men, 295 women; mean age+/-SD=64.1+/-7.7 years; 79% hypertensive) from 223 sibships recruited through > or =2 members with essential hypertension diagnosed before age 60. Leukoariosis was quantitated by magnetic resonance imaging (MRI), brain atrophy by the difference between intracranial and brain volumes, and calculated mean arterial pressure and pulse pressure provided measures of steady-state level and pulsatile components of blood pressure. After adjustment for sex and age, variance components models estimated significant heritability of leukoariosis (0.72), brain atrophy (0.52), mean arterial pressure (0.084), and pulse pressure (0.294) (P<0.0001 for each trait). Univariate maximum logarithm of odds scores (MLS) were observed for leukoariosis on chromosome 5 (MLS=1.91; P=0.00150); for brain atrophy on 1q and 17p (MLS=2.76, P=0.00018); for mean arterial pressure on 11p (MLS=1.57; P=0.00354); and for pulse pressure on 11p (MLS=3.02; P=0.00070). Bivariate linkage analyses provided evidence of loci with pleiotropic effects on brain atrophy and pulse pressure on chromosomes 11p (MLS = 5.07 at 16 cM; P=0.00001) and 16q (MLS of 4.56 at 124 cM; P=0.00003). These results demonstrate usefulness of multivariate linkage analyses to detect loci with pleiotropic effects on genetically correlated traits and suggest overlap between the genes influencing blood pressure and those contributing to brain atrophy.

Aged↗
PubMed2005

Pharmacogenetics of response to statins: where do we stand?

Cardiovascular disease is one of the leading causes of death, especially in developed countries. Blood cholesterol lowering by way of statin therapy is a common risk-lowering therapy. The risk reduction for coronary artery disease for patients using statins is 27%. These reductions, however, are average effects for all patients included in the trials. There is notable interindividual variation in response to statins, and the origins of this variation are poorly understood. Pharmacogenetics seeks to determine the role of genetic factors in variation of drug response. In patients with primary hypercholesterolemia, 23 studies have examined the effects of genetic polymorphisms at 20 different loci on the lipid response to statin treatment, and 18 studies examined genetic polymorphisms involved in the benefits of statin therapy in the prevention of cardiovascular disease. Even though many studies have been performed, few results have been replicated. It is our contention that larger sample sizes and consideration of multiple genes are needed in the field of pharmacogenetics of statin response.

Carrier Proteins↗
PubMed2005

Pleiotropic genetic effects contribute to the correlation between HDL cholesterol, triglycerides, and LDL particle size in hypertensive sibships.

OBJECTIVE: Abnormalities of HDL cholesterol (HDL-C), triglycerides, and LDL particle size are present in familial dyslipidemic hypertension. We investigated heritability of these three lipid traits and the extent to which shared effects of genes (pleiotropy) contribute to the additive genetic variation in each trait in hypertensive sibships. METHODS: Subjects included 788 individuals (60% women) ascertained through sibships with >/=2 members diagnosed with hypertension before age 60 years. The LDL particle size was measured by polyacrylamide gel electrophoresis. Triglycerides were log transformed to reduce skewness, and age- and sex-adjusted lipid traits were used in the analyses. Heritability and pairwise genetic correlations were computed using a variance components approach. The genetic correlation between a pair of traits was squared to yield genetic covariance, a measure of pleiotropic effects of genes influencing both traits concomitantly. RESULTS: Heritability estimates indicated significant genetic effects on HDL-C (0.58), log triglycerides (0.47), and LDL particle size (0.71). Genetic correlation was strongest between HDL-C and log triglycerides (-0.642), followed by log triglycerides and LDL particle size (-0.493), and HDL-C and LDL particle size (0.334). HDL-C and log triglycerides showed the strongest genetic covariance (41%), followed by LDL particle size and log triglycerides (24%), and HDL-C and LDL particle size (11%). CONCLUSIONS: Multivariate quantitative genetic analyses in hypertensive sibships reveal that pleiotropy contributes to the additive genetic variation in HDL-C, triglycerides, and LDL particle size. These findings provide the rationale for multivariate linkage analyses to identify novel genetic loci with pleiotropic effects on the traits.

Aged↗
PubMed2005

Lack of agreement between office and ambulatory blood pressure responses to hydrochlorothiazide.

BACKGROUND: Differences between the antihypertensive responses to drug therapy measured by office blood pressure (OBP) and ambulatory blood pressure monitoring (ABPM) techniques have been noted but rarely analyzed. We studied whether the OBP and 24-h ABPM responses to hydrochlorothiazide differ and, if so, the relevance of these differences. METHODS: The OBP and ABPM responses to hydrochlorothiazide (25 mg/d, for 4 weeks) were measured in 228 subjects with essential hypertension, and mean responses were compared between methods using the Student paired t test. To assess variation in the agreement between OBP and ABPM responses among subjects, the limits of agreement were calculated as the mean difference between OBP and ABPM responses +/-2 standard deviations. RESULTS: The mean systolic OBP response was 4.8 mm Hg greater than the response measured by ABPM (-14.3 v -9.5 mm Hg, P < .001), and the mean diastolic OBP response was 2.1 mm Hg greater than the response measured by ABPM (-7.5 v -5.5, P < .001). The limits of agreement between the OBP and ABPM responses ranged from -18.7 to +28.2 mm Hg for systolic response and from -12.9 to +17.1 mm Hg for diastolic response. The systolic and diastolic OBP and ABPM responses were in opposite directions in 22.8% and 23.7% of the subjects, respectively. CONCLUSIONS: Compared to ABPM, OBP overestimates the mean systolic and mean diastolic blood pressure responses to hydrochlorothiazide. Variation among subjects in the magnitude and direction of responses renders OBP an unreliable predictor of ABPM responses.

Adult↗
PubMed2005

Genome-wide linkage study of erythrocyte sodium-lithium countertransport.

BACKGROUND: Increased erythrocyte sodium-lithium countertransport (SLC) has been observed in patients with essential hypertension. An analytic strategy for identification of genetic variation contributing to hypertension is the evaluation of appropriate intermediate phenotypes for hypertension, such as SLC. Thus, in this study, genome-wide linkage scans for SLC were performed in two independent samples of pedigrees from the Rochester Family Heart Study (RFHS). METHODS: Genome-wide linkage scans for SLC were performed in independent samples of 232 and 252 non-Hispanic white families from the RFHS. Multipoint variance-component linkage analysis was performed using MERLIN. RESULTS: Chromosomes 8, 9, 10, 19, and 20 contained evidence for linkage (log of the odds [LOD] > or =2) in at least one sample of RFHS pedigrees. Consistent evidence of linkage for SLC between the two samples was observed on chromosome 10 (LOD = 2.02 at 64 cM in the first sample and LOD = 2.27 at 55 cM in the second sample). CONCLUSIONS: Consistent evidence of linkage (LOD > or =2) for SLC was observed in two independent samples of non-Hispanic white families on chromosome 10. Concordance of linkage evidence between the two samples provides confidence that a region on chromosome 10 contains genetic variation influencing SLC, which may potentially influence susceptibility to hypertension.

Antiporters↗
PubMed2005

A novel quantitative trait locus on chromosome 1 with pleiotropic effects on HDL-cholesterol and LDL particle size in hypertensive sibships.

BACKGROUND: High-density lipoprotein (HDL)-cholesterol, triglycerides, and LDL particle size are correlated lipid traits. Abnormal levels of these traits are frequent in hypertensive individuals and contribute to increased risk of coronary heart disease (CHD). We performed univariate and bivariate linkage analyses to identify genomic regions that influence levels of these traits and exert pleiotropic effects on the traits in hypertensive sibships. METHODS: Subjects included 691 non-Hispanic white individuals (mean age 63.1+/-8.5 years, 57% women, 78% hypertensive) ascertained through sibships with two or more individuals diagnosed with hypertension before age 60 years. The LDL particle size was measured by polyacrylamide gel electrophoresis and triglycerides were log-transformed to reduce skewness. Genotypes were measured at 366 microsatellite marker loci distributed across the 22 autosomes. Univariate and bivariate linkage analyses were performed using a variance components approach. RESULTS: Significant (P < .001) genetic correlations were confirmed for all pairwise combinations of the traits. Univariate linkage analyses demonstrated evidence of linkage (defined as multipoint LOD scores > or =1.3) for HDL-cholesterol on chromosomes 1p, 3p, 9q, and 18q; for log triglycerides on chromosome 10q; and for LDL particle size on chromosomes 2p and 8p. Pairwise bivariate linkage analyses of the three traits revealed a region with pleiotropic effects on HDL-cholesterol and LDL particle size on chromosome 1p (LOD score 4.48). CONCLUSIONS: These findings indicate the presence of a quantitative trait locus on chromosome 1 that has pleiotropic effects on HDL-cholesterol and LDL particle size and may therefore influence CHD susceptibility in hypertensive sibships.

Aged↗
PubMed2005

Demographic, environmental, and genetic predictors of metabolic side effects of hydrochlorothiazide treatment in hypertensive subjects.

BACKGROUND: Thiazide diuretics are recommended for first-line treatment of hypertension. Although considered safe and effective, their use is associated with dyslipidemia, hyperglycemia, and an increased risk of developing type 2 diabetes. The aim of this study was to characterize interindividual variation in glucose and lipid responses to hydrochlorothiazide and to identify demographic, environmental, and genetic predictors associated with this variation. METHODS: A community-based sample of 585 adults with essential hypertension (291 African Americans [150 women and 141 men] and 294 non-Hispanic whites [126 women and 168 men]) underwent monotherapy with hydrochlorothiazide for 4 weeks. Linear regression was used to construct prediction models for the changes in plasma total cholesterol, triglyceride, and glucose concentrations. RESULTS: The mean changes (+/- standard deviation) in response to hydrochlorothiazide were 6.13 +/- 22.8 mg/dL for total cholesterol, 17.21 +/- 70 mg/dL for triglycerides, and 3.5 +/- 9.5 mg/dL for plasma glucose. Ethnicity and baseline levels of the analytes were the only predictors that were significant for more than one response. Therefore, the mechanism for these metabolic effects are not entirely shared. CONCLUSIONS: Taken together, demographic, environmental, and genetic factors accounted for only 13% of the total variation in total cholesterol response, 17% of the variation in triglyceride response, and 11% of the variation in glucose response to hydrochlorothiazide, and less than half of this predicted variation in response was explained by measured genotypes.

Adult↗
PubMed2005

G-6A polymorphism of the angiotensinogen gene and its association with left ventricular mass in asymptomatic young adults from a biethnic community: the Bogalusa Heart Study.

BACKGROUND: Angiotensinogen (AGT), the precursor of angiotensin II and a rate limiting factor in the renin-angiotensin system, is implicated in left ventricular hypertrophy, as angiotensin II is a potent stimulator of cardiac growth. A genetic variant (G-6A) in the proximal promoter region of the AGT gene may be particularly important for changes in left ventricular mass (LVM). However, previous findings associating this variant with LVM among relatively older adults with cardiovascular morbidity are inconsistent and contradictory. METHODS: This study examined the effect of G-6A polymorphism on LVM in a biethnic (African American and white), community-based sample of 362 asymptomatic younger adults (mean age 32.5 years, 71% white, 39% male). Two-dimensional M-mode echocardiography was used to assess LVM, and the indexation of LVM for height(2.7) (LVMI) was used to adjust for body size. RESULTS: The frequency of the variant A(-6) allele was higher in subjects of African American than in white ethnicity (0.819 v 0.439, P < .0001), with carriers (GA+AA) representing 97.0% of African American as compared to 66.6% of white subjects. After adjusting for age, ethnicity (for total sample), gender, body mass index, systolic BP, and homeostasis model assessment index of insulin resistance, mean levels for both LVM and LVMI showed a significant decreasing trend with increasing gene dosage of the A(-6) allele in white subjects, African American subjects, and the total sample. CONCLUSIONS: These results indicate that the A(-6) allele frequency differs markedly between African Americans and white individuals, and that the variant allele modulates LVM and LVMI in a beneficial manner in asymptomatic young adults of white and African American ethnicities.

Adult↗
PubMed2005

Interactive effects between polymorphisms in the beta-adrenergic receptors and longitudinal changes in obesity.

We assessed interactions between polymorphisms in the beta-adrenergic receptor genes and longitudinal changes in obesity from childhood to adulthood using longitudinal data collected over a 24-year period from 1973 to 1996. Sex- and age-stratified analyses using random coefficients models were used to examine gene-gene interaction effects on obesity measures in 1179 African-American and white men and women (71% white, 57% women). Suggestive evidence for an interaction (p = 0.022) between the beta1- and beta2-adrenergic receptors was observed in men for longitudinal change in BMI. Men with Gly/Gly genotypes for both the beta1 and beta2 receptors showed significant increases (approximately 0.6%/yr) in BMI from childhood to adulthood. Women showed suggestive evidence for an interaction (p = 0.035) between the beta1- and beta3-adrenergic receptors for change over time in BMI. Women with Gly/Gly genotypes at the beta1-receptor and carrying at least one beta3-Arg allele showed notable increases in BMI. The regulation of lipolysis and development of obesity differ markedly between men and women and may be influenced by genetic polymorphisms, which contribute to the efficiency of the beta-adrenergic receptors, and hormonal effects on adrenergic receptor activity.

Black People↗
PubMed2005

Mining genetic epidemiology data with Bayesian networks application to APOE gene variation and plasma lipid levels.

There is a critical need for data-mining methods that can identify SNPs that predict among individual variation in a phenotype of interest and reverse-engineer the biological network of relationships between SNPs, phenotypes, and other factors. This problem is both challenging and important in light of the large number of SNPs in many genes of interest and across the human genome. A potentially fruitful form of exploratory data analysis is the Bayesian or Belief network. A Bayesian or Belief network provides an analytic approach for identifying robust predictors of among-individual variation in a disease endpoints or risk factor levels. We have applied Belief networks to SNP variation in the human APOE gene and plasma apolipoprotein E levels from two samples: 702 African-Americans from Jackson, MS, and 854 non-Hispanic whites from Rochester, MN. Twenty variable sites in the APOE gene were genotyped in both samples. In Jackson, MS, SNPs 4036 and 4075 were identified to influence plasma apoE levels. In Rochester, MN, SNPs 3937 and 4075 were identified to influence plasma apoE levels. All three SNPs had been previously implicated in affecting measures of lipid and lipoprotein metabolism. Like all data-mining methods, Belief networks are meant to complement traditional hypothesis-driven methods of data analysis. These results document the utility of a Belief network approach for mining large scale genotype-phenotype association data.

Apolipoproteins E↗
PubMed2005

A multilocus approach to the antihypertensive pharmacogenetics of hydrochlorothiazide.

OBJECTIVES: To assess the influence of variations in multiple candidate genes on inter-individual variation in diastolic blood pressure (DBP) response to hydrochlorothiazide. METHODS: A community-based sample of 585 adults with essential hypertension underwent monotherapy with hydrochlorothiazide for 4 weeks. In a nested case-control design, 195 individuals in the highest tertile of DBP response (responders) and 195 individuals in the lowest tertile of DBP response (non-responders) were genotyped for 45 polymorphisms in 19 candidate genes. For those polymorphisms where the set association approach found to be significantly associated with DBP response, logistic regression was performed to estimate the odds ratio (OR) for response associated variation in the identified genotype/haplotype. RESULTS: Two polymorphisms in the sodium channel gamma-subunit promotor gene, and a polymorphism in the endothelial nitric oxide synthase gene, were significantly associated with blood pressure response to hydrochlorothiazide. In the final experiment for the set association model P=0.038. In the logistic regression analyses, compared to subjects with the CT/CT haplotype of the SCNN1G gene, those with the GA/GA haplotype had OR 5.21 of being a DBP responder [95% CI 1.65-16.47]. Compared to subjects with the GT genotype of the ENOSA_rs1799983 polymorphism, those with the GG genotype had an OR 2.19 of being a DBP responder [95% CI 1.27-3.77]. CONCLUSIONS: Two polymorphisms in the sodium channel gamma-subunit promotor gene, and a polymorphism in the endothelial nitric oxide synthase gene, were associated with significant differences in odds of DBP response to hydrochlorothiazide. Follow-up studies are needed to define the functional genetic variations and their mechanisms of pharmacogenetic effects.

Antihypertensive Agents↗
PubMed2005

Genome-wide linkage scans for fasting glucose, insulin, and insulin resistance in the National Heart, Lung, and Blood Institute Family Blood Pressure Program: evidence of linkages to chromosome 7q36 and 19q13 from meta-analysis.

Genome-wide linkage analyses were performed using a multipoint variance components method in eight study groups from four multicenter networks (whites and blacks in GenNet; whites, blacks, and Mexican Americans in GENOA; whites and blacks in HyperGEN; and Asians in SAPPHIRe) that comprise the National Heart, Lung, and Blood Institute Family Blood Pressure Program (FBPP), in order to identify quantitative trait loci (QTLs) influencing fasting glucose, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR). These study populations were enriched with subjects who had elevated blood pressure. Participants fasting <8 h, those with a history of type 2 diabetes, or those on antidiabetic medications were excluded from the current investigation. These three phenotypes were suitably transformed to approximate normal distributions. Each phenotype was adjusted for the effects of age, BMI, and field center separately by sex within each of the eight network ethnicity groups before genetic analysis. A total of 8,664 subjects comprising 5,923 sibpairs from 4,043 families with 365 markers were available for conducting a meta-analysis using a modified Fisher's method of combining the P values from each of the eight scans. Evidence of linkages was found on chromosome 7q36 at 163 cM, with a logarithm of odds (LOD) score of 3.21 for HOMA-IR, and on chromosome 19q13 at 88 cM, with a LOD score of 3.33 for fasting glucose. We also found suggestive linkages (LOD score >/=2.2) on chromosome 7q36 at 163 cM, with LOD scores of 2.31 for fasting glucose and 2.26 for fasting insulin (versus the LOD score of 3.21 for HOMA-IR at this locus). In conclusion, QTLs were identified on chromosomes 7q36 and 19q13 for fasting glucose, insulin, and insulin resistance in large and multiple-ethnicity populations in the FBPP with good replications across several other independent studies for relevant traits. Follow-up dense mapping and association studies are warranted.

Adult↗
PubMed2004

Ethnicity and human genetic linkage maps.

Human genetic linkage maps are based on rates of recombination across the genome. These rates in humans vary by the sex of the parent from whom alleles are inherited, by chromosomal position, and by genomic features, such as GC content and repeat density. We have examined--for the first time, to our knowledge--racial/ethnic differences in genetic maps of humans. We constructed genetic maps based on 353 microsatellite markers in four racial/ethnic groups: whites, African Americans, Mexican Americans, and East Asians (Chinese and Japanese). These maps were generated using 9,291 subjects from 2,900 nuclear families who participated in the National Heart, Lung, and Blood Institute-funded Family Blood Pressure Program, the largest sample used for map construction to date. Although the maps for the different groups are generally similar, we did find regional and genomewide differences across ethnic groups, including a longer genomewide map for African Americans than for other populations. Some of this variation was explained by genotyping artifacts--namely, null alleles (i.e., alleles with null phenotypes) at a number of loci--and by ethnic differences in null-allele frequencies. In particular, null alleles appear to be the likely explanation for the excess map length in African Americans. We also found that nonrandom missing data biases map results. However, we found regions on chromosome 8p and telomeric segments with significant ethnic differences and a suggestive interval on chromosome 12q that were not due to genotype artifacts. The difference on chromosome 8p is likely due to a polymorphic inversion in the region. The results of our investigation have implications for inferences of possible genetic influences on human recombination as well as for future linkage studies, especially those involving populations of nonwhite ethnicity.

Black or African American↗
PubMed2004

Genetic structure, self-identified race/ethnicity, and confounding in case-control association studies.

We have analyzed genetic data for 326 microsatellite markers that were typed uniformly in a large multiethnic population-based sample of individuals as part of a study of the genetics of hypertension (Family Blood Pressure Program). Subjects identified themselves as belonging to one of four major racial/ethnic groups (white, African American, East Asian, and Hispanic) and were recruited from 15 different geographic locales within the United States and Taiwan. Genetic cluster analysis of the microsatellite markers produced four major clusters, which showed near-perfect correspondence with the four self-reported race/ethnicity categories. Of 3,636 subjects of varying race/ethnicity, only 5 (0.14%) showed genetic cluster membership different from their self-identified race/ethnicity. On the other hand, we detected only modest genetic differentiation between different current geographic locales within each race/ethnicity group. Thus, ancient geographic ancestry, which is highly correlated with self-identified race/ethnicity--as opposed to current residence--is the major determinant of genetic structure in the U.S. population. Implications of this genetic structure for case-control association studies are discussed.

Case-Control Studies↗