HTT and Huntington disease: KCC2 interacts with Htt (Shirasaki et al., 2012; Kalathur et al., 2015; Dargaei et al., 2018), and reports have linked altered CCC function to cognitive and behavioral impairments in HD, with inhibition of NKCC1 improving both cognitive (Dargaei et al., 2018) and motor (Hsu et al., 2019) deficits in various mouse models of HD.