Intriguingly, the protection was complete in MCI, but not AD lymphocytes (Salech et al., 2017), suggesting that PARP-1 inhibition might be useful at initial stages of the disease, consistent with the existence of a therapeutic window to protect from cell death at early stages of neurodegeneration, before the damage is too widespread (Salech et al., 2018). This evidence concerns the gene PARP1 and Alzheimer disease.