Pathogenic variants in KCNJ2 were first associated with Andersen Tawil Syndrome (ATS) in 2001 (Plaster et al., 2001) and until now account for 80% of the cases (Zhang et al., 2005; Haruna et al., 2007). Here, KCNJ2 is linked to Cardiodysrhythmic potassium-sensitive periodic paralysis.