CIDEA (Cell Death Inducing DFFA Like Effector A) is a lipid transferase primarily involved in lipid droplet metabolism and lipid storage regulation. Functionally, CIDEA localizes to lipid droplet surfaces and promotes unilocular lipid droplet formation by mediating fusion between lipid droplets, facilitating directional neutral lipid transfer from smaller to larger droplets 12. This fusion mechanism enlarges lipid droplets, restricts lipolysis, and favors lipid accumulation 1. CIDEA operates at a lower fusion rate than the related protein CIDEC, and transfer direction may be driven by internal pressure differences between contacting droplets. Beyond lipid metabolism, CIDEA functions as a transcriptional coactivator of CEBPB in epithelial cells, regulating expression of target genes including ID2, IGF1, PRLR, SOCS1, SOCS3, and XDH by strengthening CEBPB-promoter association and increasing histone acetylation. Recent evidence indicates CIDEA expression couples with the transcription factor Egr-1 in circadian-regulated hepatic lipid metabolism, with disrupted Egr-1/Cidea rhythmic coupling associated with age-related metabolic dysfunction and excessive triglyceride accumulation 3. When overexpressed, CIDEA induces apoptosis, though the physiological relevance remains unclear. These functions collectively position CIDEA as a key regulator of energy storage through lipid droplet dynamics and metabolic gene expression.