A genetic diagnosis guides clinical management in individuals with NDM and determines which treatment is most appropriate (for example, sulphonylureas in individuals with activating variants in the potassium channel genes KCNJ113, 4 and ABCC85, 6), and whether the diabetes occurs in isolation (isolated NDM) or is one of the first manifestations of a multiorgan disease (syndromic NDM). The gene discussed is KCNA3; the disease is neonatal diabetes mellitus.