In addition, some genes showed extensive cross-tissue effects on AD, such as AD was associated with the expression of APOE, CEACAM19, CLPTM1, DMWD, KAT8, PRSS36, PVRL2, SIX5, TRAPPC6A, PPP1R13L and PPP1R37 in at least three tissues. This evidence concerns the gene APOE and Alzheimer disease.