Astrocytes from Slc12a2 KO mice are unable to regulate their volume in response to a hyperkalemic (75 mM K+) challenge (Su et al., 2002), and NKCC1 has been implicated in astrocytic swelling in pathological conditions such as ischemia and brain edema caused by liver dysfunction (Yan et al., 2001; Jayakumar et al., 2008; reviewed in Jayakumar and Norenberg, 2010). The gene discussed is SLC12A2; the disease is ischemia.