KCNA4 and familial long QT syndrome: There are reports of decreased Kv4.3 currents with a prolongation of APD in diabetic mice (Shimoni et al., 2004), or unchanged protein levels of Kv1.4 and Kv4.2 subunits in a DIO mice despite APD prolongation (Huang et al., 2013), suggesting that the sensitivity of Ito channel function to metabolic disorders and the development of LQTS may vary depending on the underlying pathology.