Department of Biostatistics, University of Alabama at Birmingham Birmingham, AL, USA.
Front Genet. 2012 May 28;3:92. doi: 10.3389/fgene.2012.00092. eCollection 2012.
Left ventricular hypertrophy (LVH) is a heritable predictor of cardiovascular disease, particularly in blacks.
Determine the feasibility of combining evidence from two distinct but complementary experimental approaches to identify novel genetic predictors of increased LV mass.
Whole-exome sequencing (WES) was conducted in seven African-American sibling trios ascertained on high average familial LV mass indexed to height (LVMHT) using Illumina HiSeq technology. Identified missense or nonsense (MS/NS) mutations were examined for association with LVMHT using linear mixed models adjusted for age, sex, body weight, and familial relationship. To functionally assess WES findings, human induced pluripotent stem cell-derived cardiomyocytes (induced pluripotent stem cell-CM) were stimulated to induce hypertrophy; mRNA sequencing (RNA-seq) was used to determine gene expression differences associated with hypertrophy onset. Statistically significant findings under both experimental approaches identified LVH candidate genes. Candidate genes were further prioritized by seven supportive criteria that included additional association tests (two criteria), regional linkage evidence in the larger HyperGEN cohort (one criterion), and publically available gene and variant based annotations (four criteria).
WES reads covered 91% of the target capture region (of size 37.2 MB) with an average coverage of 65×. WES identified 31,426 MS/NS mutations among the 21 individuals. A total of 295 MS/NS variants in 265 genes were associated with LVMHT with q-value <0.25. Of the 265 WES genes, 44 were differentially expressed (P < 0.05) in hypertrophied cells. Among the 44 candidate genes identified, 5, including HLA-B, HTT, MTSS1, SLC5A12, and THBS1, met 3 of 7 supporting criteria. THBS1 encodes an adhesive glycoprotein that promotes matrix preservation in pressure-overload LVH. THBS1 gene expression was 34% higher in hypertrophied cells (P = 0.0003) and a predicted conserved and damaging NS variant in exon 13 (A2099G) was significantly associated with LVHMT (P = 4 × 10(-6)).
Combining evidence from cutting-edge genetic and cellular experiments can enable identification of novel LVH risk loci.
左心室肥厚（LVH）是心血管疾病的遗传性预测因子，尤其是在黑人中。
确定结合两种截然不同但互补的实验方法的证据来识别增加 LV 质量的新遗传预测因子的可行性。
使用 Illumina HiSeq 技术，在七个高平均家族性 LV 质量与身高（LVMHT）相关的非洲裔美国家族三体中进行全外显子组测序（WES）。使用线性混合模型，根据年龄、性别、体重和家族关系，对识别出的错义或无义（MS/NS）突变与 LVMHT 进行关联分析。为了功能评估 WES 结果，使用人类诱导多能干细胞衍生的心肌细胞（诱导多能干细胞-CM）刺激诱导肥大；使用 mRNA 测序（RNA-seq）来确定与肥大起始相关的基因表达差异。在两种实验方法下，都鉴定到了与 LVH 候选基因具有统计学意义的发现。候选基因通过七个支持标准进行进一步优先排序，包括额外的关联测试（两个标准）、在更大的 HyperGEN 队列中的区域连锁证据（一个标准）以及公开的基因和基于变体的注释（四个标准）。
WES 读取覆盖了 37.2MB 大小的目标捕获区域的 91%，平均覆盖率为 65×。在 21 个人中，WES 共鉴定出 31426 个 MS/NS 突变。在 265 个基因中，共有 295 个 MS/NS 变异与 LVMHT 的 q 值<0.25 相关。在 265 个 WES 基因中，有 44 个基因在肥大细胞中差异表达（P<0.05）。在鉴定出的 44 个候选基因中，有 5 个基因，包括 HLA-B、HTT、MTSS1、SLC5A12 和 THBS1，满足 7 个支持标准中的 3 个。THBS1 编码一种黏附糖蛋白，可促进压力超负荷性 LVH 中的基质保留。在肥大细胞中，THBS1 基因的表达水平升高了 34%（P=0.0003），并且在 13 号外显子中预测的保守和有害的 NS 变异（A2099G）与 LVHMT 显著相关（P=4×10（-6））。
结合前沿的遗传和细胞实验证据，可以确定新的 LVH 风险基因座。
