In the present study, we sought to explore the spatial assessment of mGluR5 distribution and tau deposition in cognitively impaired (CI) and cognitively unimpaired (CU) individuals via PET scans using [18F]PSS232 and 6‐(fluoro‐18F)‐3‐(1H‐pyrrolo[2,3‐c]pyridin‐1‐yl)isoquinolin‐5‐amine ([18F]MK6240) while exploring the associations of mGluR5 with tau deposition and their associations with AD biomarkers and cognitions. This evidence concerns the gene GRM5 and Alzheimer disease.