GWAS SNP arrays “cover” 80% or more of common HapMap SNPs, and regional resequencing data suggest that most unknown common SNPs are also being tested indirectly. Within these limitations, GWAS methods test the CDCV hypothesis. CNVs are also detected, but less systematically or accurately. The PGC meta-analyses will have reasonable power to detect common SNP associations for each disorder within the limitations shown in Figure 1. But it is possible that very few significant associations might be detected for some disorders, or none. How far should we go with GWAS?
