The only postmortem study of mGluR5 binding in AD by Müller Herde et al. [43] utilized [18F]PSS232 autoradiography and reported increases in the frontal cortex (5.2-fold) and hippocampus (2.5-fold) in 6 patients with severe AD compared to 6 controls. This evidence concerns the gene GRM5 and Alzheimer disease.