Intriguingly, mutations in SLC12A2 (encoding NKCC1) are linked with neurodevelopmental disorders, and genetic variation in SLC12A5 (encoding KCC2) is associated with epilepsy and autism (Kahle et al., 2014; Puskarjov et al., 2014; Merner et al., 2015; McNeill et al., 2020; Stödberg et al., 2020). Here, SLC12A2 is linked to epilepsy.