if the risk is 3× for , there is a 6× risk for - in this case the risk for is and the risk for is . A common practice for GWAS is to examine additive models only, as the additive model has reasonable power to detect both additive and dominant effects, but it is important to note that an additive model may be underpowered to detect some recessive effects [30]. Rather than choosing one model a priori, some studies evaluate multiple genetic models coupled with an appropriate correction for multiple testing.
