It should also be noted that our findings are in keeping with preliminary in vivo evidence in a mixed sample of healthy volunteers and patients with Alzheimer’s disease showing a significant positive association between SV2A binding and metabotropic glutamate subtype 5 receptors (mGluR5) binding via radioligand [18F]FPEB, a potential marker of glutamatergic neurotransmission, and a significant mGluR5-by-region of interest interaction effect on [11C]UCB-J VT [78]. This evidence concerns the gene GRM5 and early-onset autosomal dominant Alzheimer disease.