APEX1 and Alzheimer disease: In comparison to 110 controls, significant increases in 8-oxoG DNA content with concomitant downregulations of 8-oxoG DNA glycosylase OGG1 and MUTYH [217], other DNA glycosylase NEIL1, APE1, and PARP1 were demonstrated in the PBMCs of AD patients (n = 100) (Table 2) [218,219].