APOE and Alzheimer disease: Cruchaga et al. (2013) observed rs769449 to be associated with the CSF levels of tau and ptau proteins, two key biochemical markers of axonal degeneration, neuronal loss, and a cognitive decline in PwAD, suggesting a role of this intronic SNP in AD pathophysiology. Nevertheless, the effect of “G” to “A” substitution in this SNP has not been investigated yet. Last, the APOE genetic variant, rs7256173, has not been previously associated with AD.