Following these points, several complementary approaches exist. One alternative is a genomewide association (GWA) scan on AN. GWA studies have been successful in identifying highly replicable associations for T1DM, T2DM, Crohn’s disease, cardiovascular disease, prostate cancer, breast cancer, body mass index, nicotine addiction, and height [Bierut et al., 2007; Consortium, 2007; Frayling et al., 2007; Saxena et al., 2007; Scott et al., 2007; Berrettini et al., 2008; Thorgeirsson et al., 2008]. Whether similar successes will be realized in psychiatry remains unclear although many efforts are currently underway [Psychiatric GWAS Consortium (PGC), 2009]. Critical to note is that our approach focused on common variants (MAF >0.5%), and thus rare variation has been necessarily missed. Our results do not eliminate these genes as potential candidates for AN, but rather indicate that common variants located in them are unlikely to be the causal variants. Other approaches include searches for multiple rare variations via sequencing studies [Nejentsev et al., 2009], analysis of copy number variations [Walsh et al., 2008], accommodation and consideration of epigenomic factors [Peedicayil, 2004] and sophisticated multi-locus analyses.
