The loss of BSEP protein expression in the mtm zebrafish was intriguing because, in humans, mutations in ABCB11 (the gene that encodes BSEP) are associated with 2 forms of cholestatic liver disease: progressive familial intrahepatic cholestasis (PFIC) and benign recurrent intrahepatic cholestasis (BRIC) (12). The gene discussed is ABCB11; the disease is Cholestatic liver disease.