PCYT1A (phosphate cytidylyltransferase 1A, choline) encodes the rate-limiting enzyme in the CDP-choline pathway for phosphatidylcholine (PC) biosynthesis 1. The enzyme catalyzes a crucial step in the Kennedy pathway for de novo PC synthesis, with high expression observed in retinal Müller glial cells 1. PCYT1A plays essential roles in cellular membrane integrity and lipid metabolism. The protein is activated during autophagy and facilitates autophagosome formation by incorporating newly synthesized choline phospholipids into autophagosomal membranes 2. In immune function, PCYT1A-mediated glycerophospholipid metabolism licenses IgE-mediated mast cell degranulation and contributes to allergic disease pathophysiology 3. Genetic variants in PCYT1A are associated with spina bifida risk, with certain SNPs showing twofold increased disease risk 4. PCYT1A deficiency causes inherited retinal dystrophies through disruption of fatty acid metabolism and induction of ferroptosis in photoreceptor cells 1. The gene is also implicated in polycystic ovary syndrome through epigenetic silencing and subsequent lipidome alterations 5. These findings establish PCYT1A as a critical regulator of phospholipid metabolism with significant roles in development, immunity, and disease pathogenesis.