GRM5 and early-onset autosomal dominant Alzheimer disease: Some genes encoding postsynaptic glutamate receptors, GABAA receptors or anchoring proteins were also significantly downregulated in Alzheimer’s disease, including GRIN2A, GRIA1, GRIA2, GABRA1, GABRB2, GRM3 and SHANK2, while GRM5, SYNGAP1, SHANK3 and GRIN2B were not changed (Fig. 2C and D).