The function of ENSG00000116133 (DHCR24, 24-dehydrocholesterol reductase) is as follows. Catalyzes the reduction of the delta-24 double bond of sterol intermediates during cholesterol biosynthesis (PubMed:11519011, PubMed:21671375, PubMed:22178193, PubMed:25637936). In addition to its cholesterol-synthesizing activity, can protect cells from oxidative stress by reducing caspase 3 activity during apoptosis induced by oxidative stress (PubMed:11007892, PubMed:22010141). Also protects against amyloid-beta peptide-induced apoptosis (PubMed:11007892). {ECO:0000269|PubMed:11007892, ECO:0000269|PubMed:11519011, ECO:0000269|PubMed:21671375, ECO:0000269|PubMed:22010141, ECO:0000269|PubMed:22178193, ECO:0000269|PubMed:25637936}.