KCNJ10 and Ataxia: These nervous-system-specific Kir4.1 conditional knockout mice (termed nKir4.1cKO) exhibited retarded growth, ataxia, tremor, and early mortality, with most mice dying by postnatal day (P) 25 (Figure 1A–B; Figure 1—video 1), similar to the phenotype of Kir4.1 global knockout and glia-specific Kir4.1 knockout mice (Djukic et al., 2007; Neusch et al., 2001).