“…Many methods have been developed for testing the association of common variants with multiple traits (see Avery et al., ; Ferreira and Purcell, ; He et al., ; Hua and Ghosh, ; Liu et al., ; Maity et al., ; OReilly et al., ; Rasmussen‐Torvik et al., ; Schifano et al., ; van der Sluis et al., ; Wu and Pankow, ; Yang et al., , e.g.). In GWAS, identified common variants only explained a small proportion of the phenotypic variance for most complex traits studied to date.…”