The two liver X receptors isoforms, LXRα and β, were also detected in the RPE and choroid and are important in ocular biology and AMD pathogenesis as they can be activated by cholesterol, and regulate transcription of lipid transporters including ATP binding cassette family A, member 1 (ABCA1) and cholesterol esterase transfer protein (CETP). Here, ABCA1 is linked to age-related macular degeneration.