Activating mutations in ABCC8 and KCNJ11 are associated with a variable spectrum of phenotypes according to genotype;34 milder mutations cause transient neonatal diabetes, whereas mutations that severely affect the potassium channels' ability to respond to ATP concentrations cause permanent neonatal diabetes associated with neurological features (ie, intermediate DEND syndrome and DEND syndrome;5, 7, 30, figure 3, appendix). This evidence concerns the gene KCNJ11 and DEND syndrome.