The function of ENSG00000172893 (DHCR7, 7-dehydrocholesterol reductase) is as follows. Oxidoreductase that catalyzes the last step of the cholesterol synthesis pathway, which transforms cholesta-5,7-dien- 3beta-ol (7-dehydrocholesterol,7-DHC) into cholesterol by reducing the C7-C8 double bond of its sterol core (PubMed:25637936, PubMed:38297129, PubMed:38297130, PubMed:9465114, PubMed:9634533). Can also metabolize cholesta-5,7,24-trien-3beta-ol (7-dehydrodemosterol, 7-DHD) to desmosterol, which is then metabolized by the Delta(24)-sterol reductase (DHCR24) to cholesterol (By similarity). Modulates ferroptosis (a form of regulated cell death driven by iron-dependent lipid peroxidation) through the metabolic breakdown of the anti- ferroptotic metabolites 7-DHC and 7-DHD which, when accumulated, divert the propagation of peroxyl radical-mediated damage from phospholipid components to its sterol core, protecting plasma and mitochondrial membranes from phospholipid autoxidation (PubMed:38297129, PubMed:38297130). {ECO:0000250|UniProtKB:O88455, ECO:0000269|PubMed:25637936, ECO:0000269|PubMed:38297129, ECO:0000269|PubMed:38297130, ECO:0000269|PubMed:9465114, ECO:0000269|PubMed:9634533}. Component of the microsomal antiestrogen binding site (AEBS), a multiproteic complex at the ER membrane that consists of an association between cholestenol Delta-isomerase/EBP and DHCR7 (PubMed:15175332, PubMed:20615952). This complex is responsible for cholesterol-5,6-epoxide hydrolase (ChEH) activity, which consists in the hydration of cholesterol-5,6-epoxides (5,6-EC) into cholestane- 3beta,5alpha,6beta-triol (CT) (PubMed:20615952). The precise role of each component of this complex has not been described yet (PubMed:20615952). {ECO:0000269|PubMed:15175332, ECO:0000269|PubMed:20615952}.