Fic1 and Bsep Defects in Taiwanese Patients with Chronic Intrahepatic Cholestasis with Low γglutamyltranspeptidase Levels

To elucidate the frequency of FIC1 (ATP8B1) and BSEP (ABCB11 ) mutations in Taiwanese children with chronic intrahepatic cholestasis with low γ- glutamyltranspeptidase (GGT) levels, we assessed 13 unrelated patients with infantile onset chronic intrahepatic cholestasis. Liver complementary DNA sequencing was performed in 7 infants for mutation analyses of FIC1 and BSEP genes. Two distinct liver histologic features were found. Group 1 (n=5) was characterized by bland cholestasis and group 2 (n=8) by giant cell transformation. Group 2 patients were associated with higher transaminase levels, α-fetoprotein levels, and early mortality. Novel FIC 1 mutations were found in all 4 patients tested in group 1, including a 74 -bp deletion, a 98-bp deletion, a nonsense, and 2 missense mutations. BSEP mutations were found in 2 of the 3 patients in group 2, including 2 missense mutations and a 1-bp deletion. Phenotypic characterization is useful to differentiate FIC1- from BSEP-related disease.