FIC1 and BSEP defects in Taiwanese patients with chronic intrahepatic cholestasis with low γ-glutamyltranspeptidase levels

To elucidate the frequency of FICl (ATP8B1) and BSEP (ABCB11) mutations in Taiwanese children with chronic intrahepatic cholestasis with low gamma-glutamyltranspeptidase (GGT) levels, we assessed 13 unrelated patients with infantile onset chronic intrahepatic cholestasts. Liver complementary DNA sequencing was performed in 7 infants for mutation analyses of FICl 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, alpha-fetoprotein levels, and early mortality. Novel FICl 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 FICl- from BSEP-related disease.