ESRRG encodes estrogen-related receptor gamma (ERRγ), an orphan nuclear receptor that functions as a transcription factor regulating cellular metabolism and differentiation. ERRγ acts as a transcriptional activator in the absence of bound ligand and binds to estrogen response elements to regulate gene expression 1. The receptor plays critical roles in multiple tissues: it governs gastric stem cell differentiation into acid-secreting parietal cells by regulating metabolic transcripts and committing progenitors to the parietal cell lineage 1. In pancreatic acinar cells, ERRγ maintains cellular function and identity by regulating mitochondrial oxidative phosphorylation genes, with ERRγ deficiency leading to mitochondrial dysfunction, endoplasmic reticulum stress, and pancreatitis-like phenotypes 2. ERRγ is also involved in liver metabolism, where it regulates CYP2E1 expression and contributes to alcohol-associated liver injury through the CB1R-ERRγ-FGF23 pathway 34. Disease relevance includes its association with chr1 pancreatitis through genetic variants 2 and aberrant splicing in prolactinomas due to SF3B1 mutations, leading to excessive prolactin secretion 5. These findings highlight ERRγ as a crucial metabolic regulator with therapeutic potential across multiple organ systems.