However, 7 studies showed differences in methylation patterns of CpG sites (within same gene some CpG sites were hypomethylated and some others were hypermethylated, in AD cases) examined at the following genes: SORL1 [61], ABCA7 [61], SLC2A4 [61], BIN1 [61], HSPA8 [59], HSPA9 [59], DR4 gene [62], BDNF4 [43, 44], SIRT1 [49], APP [47], MAPT [47] and GSK3B [47]. Here, GSK3B is linked to Alzheimer disease.