Small duct primary sclerosing cholangitis without inflammatory bowel disease is genetically different from large duct disease by Næss, S, Björnsson, E, Anmarkrud, J, Mamari, SA, Juran, B, Lazaridis, K, Chapman, R, Bergquist, A, Melum, E, Marsh, S, Schrumpf, E, Lie, B, Boberg, K, Karlsen, T, Hov, JR