Of note, early-onset (< 65 years) patients were detected to have greater binding of the 11C-PBR28 ligand than late-onset patients in parietal cortex and striatum, and 11C-PBR28 binding correlated with lower age of onset [60], adding to the complexity of the interpretation of the TSPO data and our understanding of the role of microglia in AD. This evidence concerns the gene TSPO and Alzheimer disease.