ABCB4 and Decreased liver function: Differential diagnosis of diseases with features of obstruction on a liver biopsy includes total parenteral nutrition (TPN)-related hepatopathy, choledochal cyst, Alagille syndrome, α1-antitrypsin deficiency, multidrug resistance protein 3 MDR3 deficiency, cystic fibrosis, neonatal sclerosing cholangitis (NSC) or any other cause of mechanical obstruction [47,66].