CYP26C1 is a cytochrome P450 monooxygenase that catalyzes the oxidative metabolism of retinoic acid (RA), the active form of vitamin A essential for embryonic development and retinoid homeostasis 1. Unlike other CYP26 family members, CYP26C1 exhibits distinct substrate specificity, efficiently metabolizing both all-trans-RA and 9-cis-RA isomers with high intrinsic clearance, and shows reduced sensitivity to ketoconazole inhibition 12. CYP26C1 is particularly efficient at hydroxylating 4-oxo-atRA, an active retinoid metabolite, and interacts with cellular retinoic acid binding proteins (CRABPs) to facilitate substrate delivery 3. The enzyme contributes to retinoic acid homeostasis and CNS patterning, particularly in developing regions of visual acuity 1. Dysregulation of CYP26C1 has emerged as clinically significant: loss-of-function variants in CYP26C1 co-segregate with optic nerve aplasia in familial cases 4 and act as a genetic modifier of SHOX deficiency severity by elevating retinoic acid levels 5. Conversely, elevated CYP26C1 expression occurs in approximately 33% of primary breast carcinomas, correlating with tumor proliferation markers and grade 6. Additionally, CYP26C1 promoter hypomethylation has been associated with small vessel stroke in Korean populations 7.