INS and hyperinsulinism: In key early work, congenital forms of hyperinsulinemia and hypoglycemia were linked to loss of function mutations in KCNJ11 and ABCC8, encoding the pore Kir6.2 and regulatory SUR1 subunits of the pancreatic β-cell KATP channel, which indicated this channel plays a critical role in regulation of insulin secretion.1 Subsequently, gain-of-function mutations in the same genes were shown to underlie a spectrum of neonatal diabetes,2,3 which solidified the essential role of KATP channels in glucose-stimulated insulin secretion.