FADS6 (fatty acid desaturase 6) is a membrane-bound oxidoreductase that catalyzes polyunsaturated fatty acid (PUFA) biosynthesis through Δ6 desaturation of linoleic and α-linolenic acids 1. The enzyme exhibits species-specific substrate specificities that influence the omega-6/omega-3 PUFA ratio, impacting multiple signaling pathways 1. FADS6 expression is tissue-specific and transcriptionally regulated; its expression in mitochondria is conserved across mammalian tissues and largely preserved between rats and humans 2. In hepatocytes, FADS6 functions as a key effector of phosphocholine-mediated cytoprotection, facilitating polyunsaturated fatty acid production and enabling recovery of energy and redox homeostasis following cold and ischemia/reperfusion injury 3. FADS6 transcript stability is enhanced by m6A methylation in response to phosphocholine signaling 3. Disease relevance: FADS6 is differentially expressed in sebaceous glands during inflammatory skin diseases, including atopic dermatitis, suggesting a role in disease-specific lipid metabolism modulation 4. FADS6 mutations have been identified as peritoneal metastasis-specific drivers in gastric cancer associated with adverse outcomes 5, and as recurrent mutations in EBV-positive diffuse large B-cell lymphoma 6. These findings indicate FADS6 involvement in both metabolic adaptation and oncogenic processes.