In 2007, we reported the gain‐of‐function mutation of Kir6.2, isoleucine to leucine at residue 167 (I167L), which causes neonatal diabetes with severe neurological disorders known as DEND syndrome (developmental delay, epilepsy and neonatal diabetes) (Shimomura et al., 2007). Here, KCNJ11 is linked to DEND syndrome.