ABCA2 and Alzheimer disease: Under a moderate risk of AD (OR = 1.2), power analysis showed that there might be a lack of power for the meta-analyses of the 4 SNPs, including 5bp I/D of A2M (59.6%), Ser447Ter (56.6%) of LPL, rs908832 of ABCA2 (31.6%) and 267C >T of HTR6 (29.9%).