APOE and Alzheimer disease: APP, PS-1, PS-2 and APOE4 are four major genes found to be associated with AD, while genes such as TDP-43, FUS, MAPT, GRN, C9orf72, TMEM106B and VCP have been found to be commonly implicated in pathology of some forms of FTD; whereas an increased risk of LBD might be inherited through SNCA, GBA or APOE e4 gene otherwise, which is not usually considered a genetic disorder [5,10,11,12,13,14,15].