FMR1 and fragile X syndrome: Deficits in GABAergic signaling including reduced expression of GABA(A) receptor subunits, changes in the expression of the GABA synthesizing enzymes, and impaired tonic and phasic inhibition have been found in various brain regions including hippocampus, striatum, amygdala, and cortex in the Fmr1-/y (knock out; KO) mouse model of FXS [11–15].