Detecting case–control expression quantitative trait loci using locally most powerful or maximin robust rank tests

Abstract

In testing genome‐wide gene expression quantitative trait loci, efficiency robust statistical methods and their computational convenience are most relevant. For this purpose, we propose to use a modified locally most powerful rank test for the analysis of case–control expression data. This modified rank test statistic is computationally simple, robust for non‐normally distributed expression data, and asymptotically locally most powerful. It depends on the specification of a location distribution form for data but is not sensitive to misspecifications. When such a location distribution form cannot be specified, we apply Gastwirth's maximin efficiency robust rank test to gene expression data to maximize the worst Pitman asymptotic relative efficiency among a family of location distributions. We conduct simulation studies to assess their performance and use an application to real data for illustration. Copyright © 2011 John Wiley & Sons, Ltd.