ABCB4 and sclerosing cholangitis: It is unclear whether other acquired human cholestatic liver diseases such as primary sclerosing cholangitis (PSC) or primary biliary cholangitis (PBC) are linked to ABCB4 mutations, but mice with Abcb4 impairment do spontaneously develop sclerosing cholangitis with features resembling human PSC (Trauner et al., 2008; Boyer, 2013).