EIF2AK2 and Cognitive impairment: In the case of AD, increased staining of phosphorylated PKR (p-PKR) and phosphorylated eIF2α (p-eIF2α) have been observed mainly in degenerating hippocampal neurons, partially colocalized with hyperphosphorylated tau, a major hallmark of AD, and p-PKR levels are increased in cerebrospinal fluid from patients with AD and mild cognitive impairment (Mouton-Liger et al., 2012; Hugon et al., 2017), in positive correlation with cognitive decline in AD (Dumurgier et al., 2013).