arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2009.00399stat.ME
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使用相关工具变量解释两样本孟德尔随机化中的相关水平多效性

Accounting for correlated horizontal pleiotropy in two-sample Mendelian randomization using correlated instrumental variants

Qing Cheng, Baoluo Sun, Yingcun Xia, Jin Liu

摘要:

孟德尔随机化(MR)是一种强有力的方法来检查健康风险因素和观察性研究结果之间的因果关系。由于全基因组关联研究(GWAS)的激增和丰富的完全可访问的GWAS汇总统计量,已经开发了各种汇总数据的双样本MR方法来检测或解释水平多效性,主要基于变体对暴露(γ)和水平多效性(α)的影响是独立的假设。这个假设是太严格,可以很容易地违反,因为相关的水平多效性(CHP)。为了解释这种CHP,我们提出了一种贝叶斯方法MR-Corr 2,该方法使用正交投影重新参数化γ和α的二元正态分布,并在减轻CHP的影响之前使用尖峰-平板。我们开发了一个有效的算法与双吉布斯抽样。为了证明MR-Corr 2相对于现有方法的优势,我们进行了全面的模拟研究,以比较各种情况下的第一类错误控制和点估计。通过应用MR-Corr 2来研究两组复杂性状中的配对之间的关系,我们没有确定HDL-c和CAD之间的矛盾因果关系。此外,研究结果提供了一个新的视角的因果网络之间的复杂性状。所开发的R包和用于再现所有结果的代码可在https://github.com/QingCheng0218/MR.Corr2上获得。

英文摘要:

Mendelian randomization (MR) is a powerful approach to examine the causal relationships between health risk factors and outcomes from observational studies. Due to the proliferation of genome-wide association studies (GWASs) and abundant fully accessible GWASs summary statistics, a variety of two-sample MR methods for summary data have been developed to either detect or account for horizontal pleiotropy, primarily based on the assumption that the effects of variants on exposure (γ) and horizontal pleiotropy (α) are independent. This assumption is too strict and can be easily violated because of the correlated horizontal pleiotropy (CHP). To account for this CHP, we propose a Bayesian approach, MR-Corr2, that uses the orthogonal projection to reparameterize the bivariate normal distribution for γ and α, and a spike-slab prior to mitigate the impact of CHP. We develop an efficient algorithm with paralleled Gibbs sampling. To demonstrate the advantages of MR-Corr2 over existing methods, we conducted comprehensive simulation studies to compare for both type-I error control and point estimates in various scenarios. By applying MR-Corr2 to study the relationships between pairs in two sets of complex traits, we did not identify the contradictory causal relationship between HDL-c and CAD. Moreover, the results provide a new perspective of the causal network among complex traits. The developed R package and code to reproduce all the results are available at https://github.com/QingCheng0218/MR.Corr2.

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