Under complete linkage disequilibrium (LD), robust tests often have greater
power than Pearson's chi-square test and trend tests for the analysis of
case-control genetic association studies. Robust statistics have been used in
candidate-gene and genome-wide association studies (GWAS) when the genetic
model is unknown. We consider here a more general incomplete LD model, and
examine the impact of penetrances at the marker locus when the genetic models
are defined at the disease locus.