GRM5 and early-onset autosomal dominant Alzheimer disease: In line with this, the therapeutic potential of mGluR5 pharmacological modulation, in particularly allosteric inhibition, has been extensively described, e.g., in addiction (reviewed in [25,26]), Huntington’s disease [27], chronic stress and depression [28,29], Alzheimer’s disease [30], fragile X syndrome [31] and Parkinson’s disease [32].