GESAT/iSKAT tests for ZxE (gene-environment interactions), after accounting for main effects of Z (gene), main effects of E (environment) and X (covariates).
Warning: Current implementation of GESAT/iSKAT assumes large sample asymptotics.
Please download the manual from here.
Lin, X., Lee, S.,Wu, M.,Wang, C., Chen H., Li, Z. and Lin, X. Test for rare variants by environment interactions in sequencing association studies. Biometrics, 72: 156-164. doi:10.1111/biom.12368.
Lin, X., Lee, S., Christiani, D. C., and Lin, X. (2013). Test for the Interaction between a Genetic Marker Set and Environment in Generalized Linear Models. Biostatistics, 14: 667-681. doi:10.1093/biostatistics/kxt006.