Comparing odds ratios and the nominal risk conferred in the whole PCA cohort against the most recently published mega-meta studies of typical AD [16], the effect size seen at the APOE locus was significantly less strong in PCA than for typical AD (PCA: OR 2.03, typical AD: OR 2.83, P = .0007, PGC = .001, see methods). This evidence concerns the gene APOE and Alzheimer disease.