ABCG5 (ATP Binding Cassette Subfamily G Member 5): ABCG5 is a gene that encodes a protein belonging to the ATP-binding cassette transporter family. It plays a key role in regulating dietary cholesterol by working together with ABCG8 to limit the absorption of sterols in the intestines and promote their excretion from the body. Mutations in ABCG5 are linked to sitosterolemia, a rare condition characterized by elevated plant sterol levels in the blood, which can lead to atherosclerosis and cardiovascular complications.