 Mutations in CYP27A1 are associated with cerebrotendineous xanthomatosis, a rare lipid storage disease.Inhibitors of CYP27A1 may be effective as adjuvants in the treatment of ER-positive breast cancer due to inhibition of the production of 27-hydroxycholesterol (which has estrogenic actions and stimulates the growth of ER-positive breast cancer cells).Some marketed drugs that have been identified as CYP27A1 inhibitors include anastrozole, fadrozole, bicalutamide, dexmedetomidine, ravuconazole, and posaconazole.