Scientific opportunities in resilience research for cardiovascular health and wellness. Report from a National Heart, Lung, and Blood Institute workshop.

Exposure of biological systems to acute or chronic insults triggers a host of molecular and physiological responses to either tolerate, adapt, or fully restore homeostasis; these responses constitute the hallmarks of resilience. Given the many facets, dimensions, and discipline-specific focus, gaining a shared understanding of "resilience" has been identified as a priority for supporting advances in cardiovascular health. This report is based on the working definition: "Resilience is the ability of living systems to successfully maintain or return to homeostasis in response to physical, molecular, individual, social, societal, or environmental stressors or challenges," developed after considering many factors contributing to cardiovascular resilience through deliberations of multidisciplinary experts convened by the National Heart, Lung, and Blood Institute during a workshop entitled: "Enhancing Resilience for Cardiovascular Health and Wellness." Some of the main emerging themes that support the possibility of enhancing resilience for cardiovascular health include optimal energy management and substrate diversity, a robust immune system that safeguards tissue homeostasis, and social and community support. The report also highlights existing research challenges, along with immediate and long-term opportunities for resilience research. Certain immediate opportunities identified are based on leveraging existing high-dimensional data from longitudinal clinical studies to identify vascular resilience measures, create a 'resilience index,' and adopt a life-course approach. Long-term opportunities include developing quantitative cell/organ/system/community models to identify resilience factors and mechanisms at these various levels, designing experimental and clinical interventions that specifically assess resilience, adopting global sharing of resilience-related data, and cross-domain training of next-generation researchers in this field.

Implementing the National Heart, Lung, and Blood Institute's Strategic Vision in the Division of Cardiovascular Sciences-2022 Update.

Spurred by the 2016 release of the National Heart, Lung, and Blood Institute's Strategic Vision, the Division of Cardiovascular Sciences developed its Strategic Vision Implementation Plan-a blueprint for reigniting the decline in cardiovascular disease (CVD) mortality rates, improving health equity, and accelerating translation of scientific discoveries into better cardiovascular health (CVH). The 6 scientific focus areas of the Strategic Vision Implementation Plan reflect the multifactorial nature of CVD and include (1) addressing social determinants of CVH and health inequities, (2) enhancing resilience, (3) promoting CVH and preventing CVD across the lifespan, (4) eliminating hypertension-related CVD, (5) reducing the burden of heart failure, and (6) preventing vascular dementia. This article presents an update of strategic vision implementation activities within Division of Cardiovascular Sciences. Overarching and cross-cutting themes include training the scientific workforce and engaging the extramural scientific community to stimulate transformative research in cardiovascular sciences. In partnership with other NIH Institutes, Federal agencies, industry, and the extramural research community, Division of Cardiovascular Sciences strategic vision implementation has stimulated development of numerous workshops and research funding opportunities. Strategic Vision Implementation Plan activities highlight innovative intervention modalities, interdisciplinary systems approaches to CVD reduction, a life course framework for CVH promotion and CVD prevention, and multi-pronged research strategies for combatting COVID-19. As new knowledge, technologies, and areas of scientific research emerge, Division of Cardiovascular Sciences will continue its thoughtful approach to strategic vision implementation, remaining poised to seize emerging opportunities and catalyze breakthroughs in cardiovascular sciences.

A System for Phenotype Harmonization in the National Heart, Lung, and Blood Institute Trans-Omics for Precision Medicine (TOPMed) Program.

Genotype-phenotype association studies often combine phenotype data from multiple studies to increase statistical power. Harmonization of the data usually requires substantial effort due to heterogeneity in phenotype definitions, study design, data collection procedures, and data-set organization. Here we describe a centralized system for phenotype harmonization that includes input from phenotype domain and study experts, quality control, documentation, reproducible results, and data-sharing mechanisms. This system was developed for the National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine (TOPMed) program, which is generating genomic and other -omics data for more than 80 studies with extensive phenotype data. To date, 63 phenotypes have been harmonized across thousands of participants (recruited in 1948-2012) from up to 17 studies per phenotype. Here we discuss challenges in this undertaking and how they were addressed. The harmonized phenotype data and associated documentation have been submitted to National Institutes of Health data repositories for controlled access by the scientific community. We also provide materials to facilitate future harmonization efforts by the community, which include 1) the software code used to generate the 63 harmonized phenotypes, enabling others to reproduce, modify, or extend these harmonizations to additional studies, and 2) the results of labeling thousands of phenotype variables with controlled vocabulary terms.

Genomic integrity of human induced pluripotent stem cells across nine studies in the NHLBI NextGen program.

Human induced pluripotent stem cell (hiPSC) lines have previously been generated through the NHLBI sponsored NextGen program at nine individual study sites. Here, we examined the structural integrity of 506 hiPSC lines as determined by copy number variations (CNVs). We observed that 149 hiPSC lines acquired 258 CNVs relative to donor DNA. We identified six recurrent regions of CNVs on chromosomes 1, 2, 3, 16 and 20 that overlapped with cancer associated genes. Furthermore, the genes mapping to regions of acquired CNVs show an enrichment in cancer related biological processes (IL6 production) and signaling cascades (JNK cascade & NFκB cascade). The genomic region of instability on chr20 (chr20q11.2) includes transcriptomic signatures for cancer associated genes such as ID1, BCL2L1, TPX2, PDRG1 and HCK. Of these HCK shows statistically significant differential expression between carrier and non-carrier hiPSC lines. Overall, while a low level of genomic instability was observed in the NextGen generated hiPSC lines, the observation of structural instability in regions with known cancer associated genes substantiates the importance of systematic evaluation of genetic variations in hiPSCs before using them as disease/research models.

Prediction of adult class II/III obesity from childhood BMI: the i3C consortium.

BACKGROUND AND OBJECTIVES: Adult class II/III obesity (BMI ≥ 35 kg/m2) has significant adverse health outcomes. Early prevention and treatment are critical, but prospective childhood risk estimates are lacking. This study aimed to define the prospective risk of adult class II/III obesity, using childhood BMI. METHODS: Children ages 3-19 years enrolled in cohorts of the International Childhood Cardiovascular Cohort (i3C) consortium with measured BMI assessments in childhood and adulthood were included. Prospective risk of adult class II/III obesity was modeled based on childhood age, sex, race, and BMI. RESULTS: A total of 12,142 individuals (44% male, 85% white) were assessed at median age 14 [Interquartile range, IQR: 11, 16] and 33 [28, 39] years. Class II/III adult obesity developed in 6% of children with normal weight; 29% of children with overweight; 56% of children with obesity; and 80% of children with severe obesity. However, 38% of the 1440 adults with class II/III obesity (553/1440) were normal weight as children. Prospective risk of adult class II/III obesity varied by age, sex, and race within childhood weight status classifications, and is notably higher for girls, black participants, and those in the United States. The risk of class II/III obesity increased with older adult age. CONCLUSIONS: Children with obesity or severe obesity have a substantial risk of adult class II/III obesity, and observed prospective risk estimates are now presented by age, sex, race, and childhood BMI. Clinical monitoring of children's BMI for adult class II/III obesity risk may be especially important for females and black Americans.

Emerging Concepts in Precision Medicine and Cardiovascular Diseases in Racial and Ethnic Minority Populations.

Cardiovascular diseases remain the leading cause of mortality and a major contributor to preventable deaths worldwide. The dominant modifiable risk factors and the social and environmental determinants that increase cardiovascular risk are known, and collectively, are as important in racial and ethnic minority populations as they are in majority populations. Their prevention and treatment remain the foundation for cardiovascular health promotion and disease prevention. Genetic and epigenetic factors are increasingly recognized as important contributors to cardiovascular risk and provide an opportunity for advancing precision cardiovascular medicine. In this review, we explore emerging concepts at the interface of precision medicine and cardiovascular disease in racial and ethnic minority populations. Important among these are the lack of racial and ethnic diversity in genomics studies and biorepositories; the resulting misclassification of benign variants as pathogenic in minorities; and the importance of ensuring ancestry-matched controls in variant interpretation. We address the relevance of epigenetics, pharmacogenomics, genetic testing and counseling, and their social and cultural implications. We also examine the potential impact of precision medicine on racial and ethnic disparities. The National Institutes of Health's All of Us Research Program and the National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine Initiative are presented as examples of research programs at the forefront of precision medicine and diversity to explore research implications in minorities. We conclude with an overview of implementation research challenges in precision medicine and the ethical implications in minority populations. Successful implementation of precision medicine in cardiovascular disease in minority populations will benefit from strategies that directly address diversity and inclusion in genomics research and go beyond race and ethnicity to explore ancestry-matched controls, as well as geographic, cultural, social, and environmental determinants of health.

Association Between Titin Loss-of-Function Variants and Early-Onset Atrial Fibrillation.

Importance: Atrial fibrillation (AF) is the most common arrhythmia affecting 1% of the population. Young individuals with AF have a strong genetic association with the disease, but the mechanisms remain incompletely understood. Objective: To perform large-scale whole-genome sequencing to identify genetic variants related to AF. Design, Setting, and Participants: The National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine Program includes longitudinal and cohort studies that underwent high-depth whole-genome sequencing between 2014 and 2017 in 18 526 individuals from the United States, Mexico, Puerto Rico, Costa Rica, Barbados, and Samoa. This case-control study included 2781 patients with early-onset AF from 9 studies and identified 4959 controls of European ancestry from the remaining participants. Results were replicated in the UK Biobank (346 546 participants) and the MyCode Study (42 782 participants). Exposures: Loss-of-function (LOF) variants in genes at AF loci and common genetic variation across the whole genome. Main Outcomes and Measures: Early-onset AF (defined as AF onset in persons <66 years of age). Due to multiple testing, the significance threshold for the rare variant analysis was P = 4.55 × 10-3. Results: Among 2781 participants with early-onset AF (the case group), 72.1% were men, and the mean (SD) age of AF onset was 48.7 (10.2) years. Participants underwent whole-genome sequencing at a mean depth of 37.8 fold and mean genome coverage of 99.1%. At least 1 LOF variant in TTN, the gene encoding the sarcomeric protein titin, was present in 2.1% of case participants compared with 1.1% in control participants (odds ratio [OR], 1.76 [95% CI, 1.04-2.97]). The proportion of individuals with early-onset AF who carried a LOF variant in TTN increased with an earlier age of AF onset (P value for trend, 4.92 × 10-4), and 6.5% of individuals with AF onset prior to age 30 carried a TTN LOF variant (OR, 5.94 [95% CI, 2.64-13.35]; P = 1.65 × 10-5). The association between TTN LOF variants and AF was replicated in an independent study of 1582 patients with early-onset AF (cases) and 41 200 control participants (OR, 2.16 [95% CI, 1.19-3.92]; P = .01). Conclusions and Relevance: In a case-control study, there was a statistically significant association between an LOF variant in the TTN gene and early-onset AF, with the variant present in a small percentage of participants with early-onset AF (the case group). Further research is necessary to understand whether this is a causal relationship.

The International Childhood Cardiovascular Cohort (i3C) consortium outcomes study of childhood cardiovascular risk factors and adult cardiovascular morbidity and mortality: Design and recruitment.

Although it is widely thought that childhood levels of cardiovascular (CV) risk factors are related to adult CV disease, longitudinal data directly linking the two are lacking. This paper describes the design and organization of the International Childhood Cardiovascular Cohort Consortium Outcomes Study (i3C Outcomes), the first longitudinal cohort study designed to locate adults with detailed, repeated, childhood biological, physical, and socioeconomic measurements and a harmonized database. I3C Outcomes uses a Heart Health Survey (HHS) to obtain information on adult CV endpoints, using mail, email, telephone, and clinic visits in the United States (U.S.) and Australia and a national health database in Finland. Microsoft Access, REsearch Data Capture (REDCap) (U.S.), LimeSurvey (Australia), and Medidata™ Rave data systems are used to collect, transfer and organize data. Self-reported CV events are adjudicated via hospital and doctor-released medical records. After the first two study years, participants (N = 10,968) were more likely to be female (56% vs. 48%), non-Hispanic white (90% vs. 80%), and older (10.4 ±â€¯3.8 years vs. 9.4 ±â€¯3.3 years) at their initial childhood study visit than the currently non-recruited cohort members. Over 48% of cohort members seen during both adulthood and childhood have been found and recruited, to date, vs. 5% of those not seen since childhood. Self-reported prevalences were 0.7% Type 1 Diabetes, 7.5% Type 2 Diabetes, 33% hypertension, and 12.8% CV event. 32% of CV events were judged to be true. I3C Outcomes is uniquely able to establish evidence-based guidelines for child health care and to clarify relations to adult CV disease.

An APOO Pseudogene on Chromosome 5q Is Associated With Low-Density Lipoprotein Cholesterol Levels.

BACKGROUND: Elevated levels of low-density lipoprotein cholesterol (LDL-C) are a major risk factor for cardiovascular disease via its contribution to the development and progression of atherosclerotic lesions. Although the genetic basis of LDL-C has been studied extensively, currently known genetic variants account for only ≈20% of the variation in LDL-C levels. METHODS: Through an array-based association analysis in 1102 Amish subjects, we identified a variant strongly associated with LDL-C levels. Using a combination of genetic analyses, zebrafish models, and in vitro experiments, we sought to identify the causal gene driving this association. RESULTS: We identified a founder haplotype associated with a 15 mg/dL increase in LDL-C on chromosome 5. After recombination mapping, the associated region contained 8 candidate genes. Using a zebrafish model to evaluate the relevance of these genes to cholesterol metabolism, we found that expression of the transcribed pseudogene, APOOP1, increased LDL-C and vascular plaque formation. CONCLUSIONS: Based on these data, we propose that APOOP1 regulates levels of LDL-C in humans, thus identifying a novel mechanism of lipid homeostasis.

Genome-Wide Gene-Potassium Interaction Analyses on Blood Pressure: The GenSalt Study (Genetic Epidemiology Network of Salt Sensitivity).

BACKGROUND: Gene-environmental interaction analysis can identify novel genetic factors for blood pressure (BP). We performed genome-wide analyses to identify genomic loci that interact with potassium to influence BP using single-marker (1 and 2 df joint tests) and gene-based tests among Chinese participants of the GenSalt study (Genetic Epidemiology Network of Salt Sensitivity). METHODS AND RESULTS: Among 1876 GenSalt participants, the average of 3 urine samples was used to estimate potassium excretion. Nine BP measurements were taken using a random-zero sphygmomanometer. A total of 2.2 million single nucleotide polymorphisms were imputed using Affymetrix 6.0 genotype data and the Chinese Han of Beijing and Japanese of Tokyo HapMap reference panel. Promising findings (P<1.00×10-4) from GenSalt were evaluated for replication among 775 Chinese participants of the MESA (Multi-ethnic Study of Atherosclerosis). Single nucleotide polymorphism and gene-based results were meta-analyzed across the GenSalt and MESA studies to determine genome-wide significance. The 1 df tests identified interactions for ARL15 rs16882447 on systolic BP (P=2.83×10-9) and RANBP3L rs958929 on pulse pressure (P=1.58×10-8). The 2 df tests confirmed the ARL15 rs16882447 signal for systolic BP (P=1.15×10-9). Genome-wide gene-based analysis identified CC2D2A (P=2.59×10-7) at 4p15.32 and BNC2 (P=4.49×10-10) at 9p22.2 for systolic BP, GGNBP1 (P=1.18×10-8), and LINC00336 (P=1.36×10-8) at 6p21 for diastolic BP, DAB1 (P=1.05×10-13) at 1p32.2, and MIR4466 (P=5.34×10-8) at 6q25.3 for pulse pressure. The BNC2 (P=3.57×10-8) gene was also significant for mean arterial pressure. CONCLUSIONS: We identified 2 novel BP loci and 6 genes through the examination of single nucleotide polymorphism- and gene-based interactions with potassium.

The NextGen Genetic Association Studies Consortium: A Foray into In Vitro Population Genetics.

The National Heart, Lung, and Blood Institute's Next Generation Genetic Association Studies Consortium has used induced pluripotent stem cell technology to study the effects of common genetic variants in vitro. This issue of Cell Stem Cell and affiliated journals include several manuscripts describing the results of the consortium's efforts.

Genome-Wide Gene-Sodium Interaction Analyses on Blood Pressure: The Genetic Epidemiology Network of Salt-Sensitivity Study.

We performed genome-wide analyses to identify genomic loci that interact with sodium to influence blood pressure (BP) using single-marker-based (1 and 2 df joint tests) and gene-based tests among 1876 Chinese participants of the Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study. Among GenSalt participants, the average of 3 urine samples was used to estimate sodium excretion. Nine BP measurements were taken using a random zero sphygmomanometer. A total of 2.05 million single-nucleotide polymorphisms were imputed using Affymetrix 6.0 genotype data and the Chinese Han of Beijing and Japanese of Tokyo HapMap reference panel. Promising findings (P<1.00×10(-4)) from GenSalt were evaluated for replication among 775 Chinese participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Single-nucleotide polymorphism and gene-based results were meta-analyzed across the GenSalt and MESA studies to determine genome-wide significance. The 1 df tests identified interactions for UST rs13211840 on diastolic BP (P=3.13×10(-9)). The 2 df tests additionally identified associations for CLGN rs2567241 (P=3.90×10(-12)) and LOC105369882 rs11104632 (P=4.51×10(-8)) with systolic BP. The CLGN variant rs2567241 was also associated with diastolic BP (P=3.11×10(-22)) and mean arterial pressure (P=2.86×10(-15)). Genome-wide gene-based analysis identified MKNK1 (P=6.70×10(-7)), C2orf80 (P<1.00×10(-12)), EPHA6 (P=2.88×10(-7)), SCOC-AS1 (P=4.35×10(-14)), SCOC (P=6.46×10(-11)), CLGN (P=3.68×10(-13)), MGAT4D (P=4.73×10(-11)), ARHGAP42 (P≤1.00×10(-12)), CASP4 (P=1.31×10(-8)), and LINC01478 (P=6.75×10(-10)) that were associated with at least 1 BP phenotype. In summary, we identified 8 novel and 1 previously reported BP loci through the examination of single-nucleotide polymorphism and gene-based interactions with sodium.

Associations Between Genetic Variants of the Natriuretic Peptide System and Blood Pressure Response to Dietary Sodium Intervention: The GenSalt Study.

BACKGROUND: The aim of this study was to comprehensively test the association of genetic variants in the natriuretic peptide (NP) system with blood pressure (BP) response to dietary sodium intervention in a Chinese population. METHODS: We conducted a 7-day low-sodium intervention followed by a 7-day high-sodium intervention among 1,906 participants in rural China. BP measurements were obtained at baseline and each dietary intervention using a random-zero sphygmomanometer. Linear mixed-effect models were used to assess the associations of 48 single-nucleotide polymorphisms (SNPs) in 6 genes of NP system with BP response to dietary sodium intervention. RESULTS: SNP rs5063 in the NPPA gene and SNP rs2077386 in the NPPC gene exhibited significant associations with BP response to low-sodium dietary intervention under recessive genetic model. For rs5063, absolute mean arterial pressure responses (95% confidence interval) to the low-sodium intervention were 1.31 (-1.08, 3.70) mm Hg for TT genotype and -3.74 (-4.01, -3.46) mm Hg for CC or TC genotype, respectively (P = 4.1 × 10(-5)). Individuals with at least one copy of the C allele of rs2077386 had significantly reduction in systolic BP during the low-sodium intervention compared to those with genotype GG with responses of -5.48 (-5.83, -5.14) vs. -2.76 (-3.52, -2.00) mm Hg, respectively (P = 1.9 × 10(-13)). CONCLUSIONS: These novel findings suggested that genetic variants of NP system may contribute to the variation of BP response to sodium intervention in Chinese population. Certainly, replication of these results in other populations and further functional studies are warranted to clarify their role in the regulation of BP and hypertension.

Genome-wide linkage and positional association analyses identify associations of novel AFF3 and NTM genes with triglycerides: the GenSalt study.

We conducted a genome-wide linkage scan and positional association study to identify genes and variants influencing blood lipid levels among participants of the Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study. The GenSalt study was conducted among 1906 participants from 633 Han Chinese families. Lipids were measured from overnight fasting blood samples using standard methods. Multipoint quantitative trait genome-wide linkage scans were performed on the high-density lipoprotein, low-density lipoprotein, and log-transformed triglyceride phenotypes. Using dense panels of single nucleotide polymorphisms (SNPs), single-marker and gene-based association analyses were conducted to follow-up on promising linkage signals. Additive associations between each SNP and lipid phenotypes were tested using mixed linear regression models. Gene-based analyses were performed by combining P-values from single-marker analyses within each gene using the truncated product method (TPM). Significant associations were assessed for replication among 777 Asian participants of the Multi-ethnic Study of Atherosclerosis (MESA). Bonferroni correction was used to adjust for multiple testing. In the GenSalt study, suggestive linkage signals were identified at 2p11.2‒2q12.1 [maximum multipoint LOD score (MML) = 2.18 at 2q11.2] and 11q24.3‒11q25 (MML = 2.29 at 11q25) for the log-transformed triglyceride phenotype. Follow-up analyses of these two regions revealed gene-based associations of charged multivesicular body protein 3 (CHMP3), ring finger protein 103 (RNF103), AF4/FMR2 family, member 3 (AFF3), and neurotrimin (NTM) with triglycerides (P = 4 × 10(-4), 1.00 × 10(-5), 2.00 × 10(-5), and 1.00 × 10(-7), respectively). Both the AFF3 and NTM triglyceride associations were replicated among MESA study participants (P = 1.00 × 10(-7) and 8.00 × 10(-5), respectively). Furthermore, NTM explained the linkage signal on chromosome 11. In conclusion, we identified novel genes associated with lipid phenotypes in linkage regions on chromosomes 2 and 11.

Associations of Endothelial System Genes With Blood Pressure Changes and Hypertension Incidence: The GenSalt Study.

BACKGROUND: We used single-marker and novel gene-based methods to examine the associations of endothelial system genes with blood pressure (BP) changes and hypertension in a longitudinal family study. METHODS: The Genetic Epidemiology Network of Salt Sensitivity follow-up study was conducted among 1,768 Chinese participants from 633 families. Nine BP measurements were obtained at baseline and at 2 follow-up visits using a random-zero sphygmomanometer. Mixed-effect models were used to assess the additive associations of 206 single-nucleotide polymorphisms (SNPs) in 15 endothelial system genes with longitudinal BP changes and hypertension incidence. Gene-based analyses were conducted using the truncated product method. The Bonferroni method was used to adjust for multiple testing in all analyses. RESULTS: Among those free from hypertension at baseline, 512 (32.1%) developed hypertension during the average 7.2 years of follow-up. In single-marker analyses, each copy of the minor alleles of correlated SELE markers rs4656704, rs6427212, and rs5368 were associated with increased risk of developing hypertension (P for trend = 1.48 × 10(-4), 6.69 × 10(-5), and 7.64 × 10(-5), respectively). In addition, the minor allele of SELE marker rs3917436 was associated with smaller diastolic BP (DBP) increases over time. Results of gene-based analyses confirmed associations of the SELE gene with the longitudinal BP phenotypes (P values < 1.00 × 10(-6) for DBP change and hypertension incidence). Furthermore, the DDAH1 and COL18A1 genes were associated with systolic BP change (P < 1.00 × 10(-6) and P = 4.00 × 10(-6), respectively), while EDNRA was associated with hypertension incidence (P = 2.39 × 10(-4)). CONCLUSIONS: The current study provides strong evidence of a role of endothelial system genes in BP progression and hypertension incidence.

Genome-wide linkage and regional association study of blood pressure response to the cold pressor test in Han Chinese: the genetic epidemiology network of salt sensitivity study.

BACKGROUND: Blood pressure (BP) response to cold pressor test (CPT) is associated with increased risk of cardiovascular disease. We performed a genome-wide linkage scan and regional association analysis to identify genetic determinants of BP response to CPT. METHODS AND RESULTS: A total of 1961 Chinese participants completed the CPT. Multipoint quantitative trait linkage analysis was performed, followed by single-marker and gene-based analyses of variants in promising linkage regions (logarithm of odds ≥2). A suggestive linkage signal was identified for systolic BP response to CPT at 20p13 to 20p12.3, with a maximum multipoint logarithm of odds score of 2.37. On the basis of regional association analysis with 1351 single nucleotide polymorphisms in the linkage region, we found that marker rs2326373 at 20p13 was significantly associated with mean arterial pressure responses to CPT (P=8.8×10(-6)) after false discovery rate adjustment for multiple comparisons. A similar trend was also observed for systolic BP response (P=0.03) and diastolic BP response (P=4.6×10(-5)). Results of gene-based analyses showed that variants in genes MCM8 and SLC23A2 were associated with systolic BP response to CPT (P=4.0×10(-5) and 2.7×10(-4), respectively), and variants in genes MCM8 and STK35 were associated with mean arterial pressure response to CPT (P=1.5×10(-5) and 5.0×10(-5), respectively). CONCLUSIONS: Within a suggestive linkage region on chromosome 20, we identified a novel variant associated with BP responses to CPT. We also found gene-based associations of MCM8, SLC23A2, and STK35 in this region. Additional work is warranted to confirm these findings. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov; Unique identifier: NCT00721721.

Linkage analysis incorporating gene-age interactions identifies seven novel lipid loci: the Family Blood Pressure Program.

OBJECTIVE: To detect novel loci with age-dependent effects on fasting (≥ 8 h) levels of total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides using 3600 African Americans, 1283 Asians, 3218 European Americans, and 2026 Mexican Americans from the Family Blood Pressure Program (FBPP). METHODS: Within each subgroup (defined by network, race, and sex), we employed stepwise linear regression (retention p ≤ 0.05) to adjust lipid levels for age, age-squared, age-cubed, body-mass-index, current smoking status, current drinking status, field center, estrogen therapy (females only), as well as antidiabetic, antihypertensive, and antilipidemic medication use. For each trait, we pooled the standardized male and female residuals within each network and race and fit a generalized variance components model that incorporated gene-age interactions. We conducted FBPP-wide and race-specific meta-analyses by combining the p-values of each linkage marker across subgroups using a modified Fisher's method. RESULTS: We identified seven novel loci with age-dependent effects; four total cholesterol loci from the meta-analysis of Mexican Americans (on chromosomes 2q24.1, 4q21.21, 8q22.2, and 12p11.23) and three high-density lipoprotein loci from the meta-analysis of all FBPP subgroups (on chromosomes 1p12, 14q11.2, and 21q21.1). These loci lacked significant genome-wide linkage or association evidence in the literature and had logarithm of odds (LOD) score ≥ 3 in the meta-analysis with LOD ≥ 1 in at least two network and race subgroups (exclusively of non-European descent). CONCLUSION: Incorporating gene-age interactions into the analysis of lipids using multi-ethnic cohorts can enhance gene discovery. These interaction loci can guide the selection of families for sequencing studies of lipid-associated variants.