NR3C1 encodes the glucocorticoid receptor (GR), a ligand-activated transcription factor that serves as a master regulator of stress responses and metabolic homeostasis. As a steroid hormone receptor, NR3C1 binds glucocorticoids and DNA to modulate transcription through both activation and repression mechanisms 1. The gene produces multiple isoforms with differential transcriptional activities, with certain variants showing lowest activation capacity 2. NR3C1 functions through classical nuclear receptor mechanisms involving TBP binding, RNA polymerase II recruitment, and interaction with Hsp90 chaperones, enabling responses to glucocorticoids, dexamethasone, and TGF-β signaling. Pathologically, NR3C1 mutations cause generalized glucocorticoid resistance (Chr5 syndrome), a rare disorder producing tissue-wide insensitivity to glucocorticoids 3. NR3C1 variants also influence HPA axis-related phenotypes in major depression, with specific polymorphisms predicting attention, working memory, and verbal memory performance independent of cortisol levels 4. Epigenetically, perinatal stress induces NR3C1 promoter hypermethylation, associating with adverse long-term health outcomes 56. Clinically, elevated NR3C1 expression driven by super-enhancers promotes chemotherapy resistance in gastric cancer and supports oncogenic gene expression in lymphomas by preventing repressor binding 78. In pancreatic β-cells, NR3C1 activation paradoxically drives excessive autophagy under metabolic stress, impairing insulin secretion and promoting diabetes 9.