This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This enzyme is a microsomal vitamin D hydroxylase that converts vitamin D into the active ligand for the vitamin D receptor. A mutation in this gene has been associated with selective 25-hydroxyvitamin D deficiency.CYP2R1 (Cytochrome P450 Family 2 Subfamily R Member 1) is a Protein Coding gene. Diseases associated with CYP2R1 include Rickets Due To Defect In Vitamin D 25-Hydroxylation and Hypocalcemic Vitamin D-Dependent Rickets. Among its related pathways are Cytochrome P450 - arranged by substrate type and cholesterol biosynthesis I. GO annotations related to this gene include iron ion binding and oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen. An important paralog of this gene is CYP2J2.