Key enzyme in the cholesterol biosynthesis pathway. Catalyzes the cyclization of (S)-2,3 oxidosqualene to lanosterol, a reaction that forms the sterol nucleus (PubMed:14766201, PubMed:7639730, PubMed:26200341). Through the production of lanosterol may regulate lens protein aggregation and increase transparency (PubMed:26200341). (S)-2,3-epoxysqualene = lanosterol Terpene metabolism; lanosterol biosynthesis; lanosterol from farnesyl diphosphate: step 3/3. Monomer. Widely expressed. Expressed in the hair bulb, the outer root sheath and hair matrix of the hair follicle epithelium. Also detected in dermal papilla, epidermis, sweat glands, sebaceous glands, and blood vessels. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Belongs to the terpene cyclase/mutase family.