Truncated exact test for two-stage case-control design for studying rare genetic variants The first stage is screening to detect rare variants in only cases. If the number of case-carriers of any rare variants exceeds a user-specified threshold, then additional cases and controls are genotyped for the detected variants and carrier status of these variants are compared for all cases and controls in the second stage. The package includes two main functions, trex for the exact test and optimalDesign to determine potential two-stage designs including an optimal design. Software Depends: R (>= 2.7.0) Jason P. Sinnwell <sinnwell.jason@mayo.edu> Schaid DJ, Sinnwell JP GPL-2 file LICENSE (http://CRAN.R-project.org/package=trex/LICENSE) 2010-04-09 application/tgz http://CRAN.R-project.org/package=trex