A meta-analysis of 28 studies consisting of participants with mild CI (n = 168), Alzheimer’s disease (n = 269), and healthy controls (n = 318) showed a significant increase in the levels of translocator protein (TSPO), indicating microglial activation [82], in the brains of subjects with mild CI and Alzheimer’s disease when compared with the brains of the healthy controls [83]. The gene discussed is TSPO; the disease is early-onset autosomal dominant Alzheimer disease.