APOE and Alzheimer disease: In 2006, Shibata et al. reported that ABCA1-A allele frequency was significantly higher in APOE-ε4 carriers compared with ε4 non-carriers.[7] Therefore it was decided to investigate about this finding, but stratification by gender and APOE-ε4 allele did not change the result and there was no association between genotypes and alleles of ABCA1 and the risk of AD among APOE-ε4 carriers and non-carriers.