KCNE1 and long QT syndrome 5: Murine models have also been useful in studying the consequences of alterations in the potassium (K+) channel, such as mutations in the KCNE1 subunit resulting in LQT5 (Balasubramaniam et al., 2003; Vetter et al., 1996) and of acute conditions such as hypokalaemia (Killeen et al., 2007).