Most common variants that have been found associated with disease through GWAS typically have very small effects on the variability of the trait and explain a rather small portion of the heritability [8]. These initial findings suggested that many GWAS may have not been sufficiently powered to discover associations with such small effects and therefore stimulated the creation of consortia to merge results from several GWAS [99–101,103,104] in order to reach sufficient statistical power to identify smaller and smaller genetic effects. Increasing sample size indeed provides the required power, but the clinical significance of these findings remains an open question.
