A substantial literature has emerged in recent years describing attempts to take a locus identified via GWAS and attempt to show association with a relevant intermediate phenotype. This, in principle, could provide insight into the mechanistic pathway between genetic variation and disease. An example is that of six markers for schizophrenia identified using GWAS and selected for further testing for association with a number of relevant cognitive measures [64]. Five out of the six variants showed no association at a 5% significance threshold, while one (rs6904071 on chromosome 6) was associated with episodic memory in the predicted direction (the disease predisposing allele reduced performance on the cognitive task).
