This study was also limited to two analytic methods for examining joint genetic effects. A variety of methods are available to investigate how multiple genetic variants contribute jointly to a dichotomous trait. In addition to the RPM and the traditional logistic regression, there are other partition-based methods [e.g. the Combinatorial Partition Method (CPM) (Nelson et al. 2001), multifactor dimensionality reduction (MDR) (Hahn et al. 2003), the Generalized MDR (GMDR) (Lou et al. 2007)], as well as information theory based methods [e.g. k-way interaction information (KWII) and total correlation information (TCI) (Chanda et al. 2007)], and a variety of other approaches. Because these approaches each have their advantages for detecting joint effects, an analysis using multiple methods can identify additional signals that might have been missed by a single method, as well as provide increased confidence in signals that are identified by multiple methods.
