CYP4A22 is a cytochrome P450 enzyme that catalyzes omega- and (omega-1)-hydroxylation of medium-chain fatty acids, including laurate and palmitate 1. Functional characterization through heterologous expression demonstrates that CYP4A22 exhibits fatty acid hydroxylation activity, though its omega-hydroxylation capability is limited by a spacious active site compared to related enzymes, with substrate recognition mediated by key residues R96 and R233 1. The enzyme shows no activity toward arachidonic acid or prostaglandin A1 and lacks functional contribution to renal 20-hydroxyeicosatetraenoic acid biosynthesis 2. CYP4A22 functions as a novel 25-hydroxylase for vitamin D3 metabolism, with loss-of-function mutations causing vitamin D-dependent rickets type 1C (VDDR1C), characterized by early-onset rickets and dentin abnormalities 3. Genetic polymorphisms in CYP4A22 are functionally significant, with multiple missense mutations identified across diverse populations 45. Several CYP4A22 SNPs (rs12564525, rs2056900, rs4926581) are associated with altered susceptibility to cardiovascular diseases, including coronary heart disease and cerebral stroke in population studies 67. The enzyme's structural features and genetic variants suggest potential roles in lipid metabolism and vascular homeostasis beyond vitamin D metabolism.