The exceptions to this are several knockout studies that have linked various DGK isoforms with epilepsy [DGKβ (Ishisaka et al., 2103), DGKδ (Leach et al., 2007) and DGKε (Rodriguez de Turco et al., 2001)] and bipolar disorder [DGKβ (Kakefuda et al., 2010; Squassina et al., 2009) and DGKη (Baum et al., 2007; Moya et al., 2010)]. This evidence concerns the gene DGKH and bipolar disorder.