PSEN1 and Alzheimer disease: Intriguingly, microglia in familial AD patient carrying mutation in PS1 gene who died at the young age were homogeneously distributed in the frontal cortex with a greater IBA1 protein levels and a higher cellular density compared to the AD patient carrying APPA673V mutations, which exhibited a specific distribution of microglia around amyloid plaques (Sorrentino et al., 2021).