If power and coverage are low, we can anticipate false negatives (i.e., true susceptibility loci with non-significant candidate gene findings). For example, GWAS and replication efforts support TCF4 as a risk locus for schizophrenia (Stefansson et al., 2009). However, a TCF4 CAG repeat was studied for association with schizophrenia in three studies (Bowen et al., 2000, McInnis et al., 2000, Vincent et al., 1999). All reported negative results which may have lead to the inappropriate exclusion of TCF4 from consideration.
