NEUROD1 and hyperinsulinemic hypoglycemia, familial, 4: OsIRO2, a bHLH (basic Helix-Loop-Helix) transcription factor induced by Fe-deficiency, is the regulator of Fe-deficiency responsive genes in roots, such as the genes OsNAS1 (nicotianamine synthase 1), OsNAS2, OsNAAT1 (nicotianamine amino-transferase 1), OsDMAS1 (deoxymugineic acid synthase 1) and the DMA-Fe3+ transporter OsYSL15 [80].