KCNJ11 and congenital isolated hyperinsulinism: In addition to protein misfolding, recently a Kir6.2 mutation E282K identified in a case of histological focal CHI (due to combination of a paternal KATP mutation and clonal loss of heterozygosity of 11p15) was reported to diminish surface expression of KATP channels by disrupting a di-acidic ER exit signal in Kir6.2 involved in concentration of the channel protein into COPII vesicles without affecting channel protein folding (Taneja et al., 2009).