ABCB11 (c.1708G > A [P.Ala570Thr]) mutation was detected in two, ABCB4 (c.1714C > T [p.Gln572Ter]) in two, and ATP8B1 (c.589-592 > A [p.Gly197Arg]) in three of our PFIC patients, and c.3020C >T [p.Pro1007Leu] mutation was identified in two of our Niemann-Pick type C1 patients. This evidence concerns the gene ABCB4 and progressive familial intrahepatic cholestasis.