HyperGEN: Genetics of Left Ventricular Hypertrophy

描述（由申请人提供）：左心室（LV）重塑和肥大在一般人群中经常发生，是心肌梗死、心力衰竭和卒中的强预测因子。以前在家庭血压计划（FBPP）的HyperGEN和GENOA研究中收集的数据已经通过连锁研究和全基因组关联研究指出了导致LV肥大和尺寸性状的遗传位点。尽管取得了这些进展，LV性状的大部分变异仍无法解释。我们假设，在某种程度上，罕见的变异解释了这种变异。我们提出以下目标。 目标1。全外显子组序列（WES）1，200 AA不相关高血压患者，超声心动图LV质量/hgt2.7的极值，以确定导致LV质量和相关结构和功能表型的罕见和低频变异。我们将从LV质量指数的上四分位数和下四分位数中选择无关个体。由于FBPP中LV质量/hgt2.7的分布偏移至高于一般人群的值，因此上四分位数的临界点约等于LVH的定义。我们将以足以捕获罕见变体的密度进行测序。我们将进行基于极端表型的分析，按功能和保守性加权，以识别高影响力的编码变体。基于来自诱导多能干细胞（iPSC）衍生的心肌细胞中的统计学和生物信息学分析以及表达实验的证据，将基因列表排序用于目标2中的选择。目标2.通过对所有AA HyperGEN/GENOA家族成员中的40个候选基因进行重新测序，在Aim 1中检测到突变体，随后在外部队列中验证768个最重要的突变体。我们将对目标1中未测序的FBPP家族和兄弟姐妹的其余部分（n= 2，266）中的所有外显子和调控区进行测序。我们将进行关联分析，然后进行生物信息学过滤，以识别高影响力的编码变体，并对768个最重要的变体进行排名，以进行进一步的外部复制。我们将使用Illumina检测试剂盒（即JHS、CARDIA、ARIC、CHS、WUSTL）对来自基于人群的研究的9，160名AA（5，623名高血压）参与者进行基因分型。将在队列内检查基于基因的关联，并在队列间进行荟萃分析。基因将根据统计学和生物学证据进行排名，以转移到目标3。目标3。使用人iPSC心肌细胞功能验证Aim 2中复制的变体。使用肥大诱导的心肌细胞，我们将测试与Aim 2罕见变异相关基因的作用方向和临床特征。我们将使用siRNA转染来测试候选基因的敲低是否影响基于细胞的模型中的肥大。本文提出的研究如果成功，将继续HyperGEN和GENOA在识别导致LV肥大的新基因方面的成功，并评估它们在基于细胞的系统中的相关性，以识别未来治疗的新途径。

DESCRIPTION (provided by applicant): Left ventricular (LV) remodeling and hypertrophy occurs frequently in the general population and is a strong predictor of myocardial infarction, heart failure, and stroke. Data previously collected in the HyperGEN and GENOA studies of the Family Blood Pressure Program (FBPP) have pointed to genetic loci contributing to LV hypertrophy and dimensional traits through linkage studies and genome-wide association studies. Despite these advances, a large portion of variation in LV traits is unaccounted for. We hypothesize that, in part, rare variants account for this variation. We propose the following aims. Aim 1. Whole exome sequence (WES) 1,200 AA unrelated hypertensives with extreme values for echocardiographic LV mass/hgt2.7 to identify rare and low-frequency variants contributing to LV mass and related structural and functional phenotypes. We will select unrelated individuals from the top and bottom quartile of LV mass index. Because the distribution of LV mass/hgt2.7 in the FBPP is shifted to higher values than the general population, the cutpoint for the upper quartile is approximately equal to the definition of LVH. We will sequence at a density sufficient to capture rare variants. We will conduct extreme phenotype-based analysis, weighted by function and conservation, to identify high-impact coding variants. A gene list will be ranked for selection in Aim 2 based on evidence from statistical and bioinformatic analyses and expression experiments in induced pluripotent stem cell- (iPSC-)derived cardiomyocytes. Aim 2. Validate variants detected in Aim 1 by resequencing 40 candidate genes in all AA HyperGEN/GENOA family members, and subsequently validate 768 most significant variants in external cohorts. We will sequence all exons and regulatory regions in the remainder of the FBPP families and siblings not sequenced in Aim 1 (n=2,266). We will conduct association analysis followed by bioinformatic filtering to identify high-impact coding variants and rank the 768 most significant variants for further external replication. We will genotype these in 9,160 AA (5,623 hypertensive) participants from population-based studies using Illumina assays (ie, JHS, CARDIA, ARIC, CHS, WUSTL). Gene-based associations will be examined within and meta-analyzed among cohorts. Genes will be ranked by statistical and biological evidence to move to Aim 3. Aim 3. Use human iPSC cardiomyocytes to functionally validate variants replicated in Aim 2. Using hypertrophy-induced cardiomyocytes, we will test the direction of effect and clinical characterization of associated genes with rare variants from Aim 2. We will use siRNA transfections to test whether knock down of candidate genes influences hypertrophy in the cell-based model. The research proposed herein, if successful, will continue the success of HyperGEN and GENOA in identifying novel genes contributing to LV hypertrophy, and evaluate their relevance in a cell-based system to identify new pathways for future treatment.