In tune with our current results, previous studies showed a reduction of KCC2 protein expression in the hippocampus of VPA rats at P15 (Tyzio et al., 2014) and P30 (Haratizadeh et al., 2023; Tyzio et al., 2014) and the hippocampus of Fmr1-KO mice, model of Fragile X syndrome (FRX) (rare type of ASD) at P15 and P30 (Tyzio et al., 2014). The gene discussed is SLC12A5; the disease is fragile X syndrome.