GWA studies in other domains yielded many associations but of even smaller effect size which means that they will prove more difficult to replicate. The initial surge of GWA research culminated in the groundbreaking Wellcome Trust Case Control Consortium (WTCCC) which reported GWA results for 500,000 SNPs genotyped for seven common disorders each with 2000 cases and 3000 shared controls in collaboration with 50 research teams (WTCCC, 2007). More than 20 significant associations were reported across the disorders, including one for bipolar disorder, the only psychiatric disorder among the seven disorders.
