ATP-binding cassette sub-family G member 8 (ABCG8) is a transporter that plays an indispensable role in the selective transport of the dietary cholesterol in and out of the enterocytes and in the selective sterol e, Xenopus/Amphibian,cretion by the liver into bile. Genetic variations in ABCG8 can be associated with susceptibility to gallbladder disease type 4 (GBD4). Defects in ABCG8 are also a cause of sitosterolemia (SITOST), also known as phytosterolemia or shellfish sterolemia. It is a rare autosomal recessive disorder characterized by increased intestinal absorption of all sterols including cholesterol,Porcinelant and shellfish sterols, and decreased biliary e, Xenopus/Amphibian,cretion of dietary sterols into bile.