Conducting meta-analysis – the combined analysis of summary results from multiple primary studies – is now known to be crucial in the identification of robust genetic signals. This general principle has been identified on multiple occasions as evidenced by studies of Crohn’s disease, type 2 diabetes mellitus, and type 1 diabetes mellitus (Barrett et al., 2008, Zeggini et al., 2008, Barrett et al., 2009). As discussed above, the PGC is conducting such analyses for psychiatric disorders.
