ABCG5 (ATP Binding Cassette Subfamily G Member 5): ABCG5 is a gene that encodes a protein in the ATP-binding cassette transporter family. It plays a crucial role in regulating dietary cholesterol by partnering with ABCG8 to limit sterol absorption in the intestines and promote their elimination from the body. Mutations in ABCG5 are associated with sitosterolemia, a rare disorder marked by high levels of plant sterols in the blood, which can result in atherosclerosis and cardiovascular issues.