PRKN and hyperinsulinemic hypoglycemia, familial, 4: A recent LC-MS metabolomic study on iPSC-derived neurons with parkin deficiency due to PARK2 mutation reveals increased TCA cycle activity resulting in elevated levels of the TCA cycle intermediates citrate, isocitrate, alpha-ketoglutarate, succinate fumarate, malate, and oxaloacetate [218].