The frontal and occipital cortex of AD cases had the highest and second-highest %area occupied by CD163 immunoreactive microglia, respectively (p < 0.001), while in PD cases the substantia nigra (SN) and dorsal motor nucleus of the vagus nerve (DMV) had the highest and second-highest %area occupied by CD163 immunoreactive microglia, respectively (p < 0.001). This evidence concerns the gene CD163 and Alzheimer disease.