SLC12A2 and Rett syndrome: In addition, anti-NKCC1 gene therapy or positive modulation of KCC2 overexpression by IGF1 and oxytocin have also been shown to be useful in treating cognitive deficits in a DS (Parrini et al., 2021) and Rett Syndrome mouse models (Tang et al., 2016; Bertoni et al., 2021), respectively.