ABCG2 and Dubin-Johnson syndrome: Multidrug resistance-associated protein 2 (Mrp2), encoded by Abcc2, belongs to the ABC transporter family, is localized on the canalicular membrane of hepatocytes, and mediates biliary excretion of organic anions including bilirubin glucuronides and glutathione conjugates.21,22 In humans, a genetic deficiency in ABCC2 results in Dubin–Johnson syndrome (DJS), a rare autosomal recessive liver disease.