GABRB3 and Alzheimer disease: A decreased level of GABA receptor subunits such as GABRA1, GABRA5, GABRB1, GABRB2, GABRB3, GABRG1, GABRG2 and GABRG3 have been observed at the transcriptional and protein levels in the hippocampus of AD patients [39,40,41,42,43].