Since OGG1 expression level was reduced in all groups except SCI, but also in patients with normal CSF levels of Aβ-42 and tau, we suggest that suppressed or reduced OGG1 function is not directly associated with Aβ or tau pathology, but that lower OGG1 transcript levels may indicate a DNA repair deficit in patients with MCI, MCI/AD and AD. Here, OGG1 is linked to Alzheimer disease.