APOE and Alzheimer disease: However, allowing for the fact that the confidence intervals are inevitably large, it is notable that the estimates for the odds ratios for APOE, CR1, and ABCA7, and the putative genes identified in our exploratory GWAS were similar or larger in the proportion with molecular evidence for AD, suggesting that the risk we identify are likely to be for the AD variant of PCA, rather than for the syndrome per se.