These controls have already been described in previous studies[11,25,26]. Specifically, pregnant controls were all healthy, as selleck chem inhibitor defined by normal serum levels of transaminases, bilirubin, ��-GT, alkaline phosphatase (AP) and bile acids. Caucasian controls from the study of Pauli-Magnus and coworkers[26] (n = 95) were healthy volunteers recruited for participation in phaseIstudies, with uneventful medical history and normal blood biochemistry. Neither of these two control groups took any regular medication. In the case of the Caucasian control population of Meier and coworkers[25] (n = 110), most patients suffered from extrahepatic malignancies, and cholestatic disease was excluded in all patients. Furthermore, none of these patients used medication known to be associated with the development of cholestasis.

For lack of DNA availability, only 110 out of 205 Caucasian controls could be used for MRP2 sequencing. For the same reason, a new group of Caucasian women with uneventful pregnancies (n = 42) had to be collected for the MRP2 variants. Demographic data and pregnancy course of these women did not differ from the previous control group. Diagnosis of ICP was based upon: (1) a clinical history of pruritus, which occurred in the third trimester of pregnancy; (2) the presence of laboratory abnormalities suggestive of ICP: fasting serum bile acid �� 1.5 ULN (upper limit of normal) and/or serum AP levels �� 1.5 ULN and/ or alanine aminotransferase (ALT) levels �� 1.5 ULN; and (3) spontaneous resolution of clinical symptoms and laboratory findings after delivery.

Diagnosis of CIC was based upon laboratory abnormalities as defined for ICP and the exclusion of preexisting liver disease defined by: (1) a negative serology for hepatitis A, B and C; (2) the exclusion of other preexisting medical conditions that could explain liver injury, such as congestive heart failure, systemic infection, or malignancy; (3) normal liver ultrasound; and (4) a clear causal relationship to drug intake. Each case of ICP and CIC was evaluated by at least one obstetrician and one hepatologist, as well as by a clinical pharmacologist. Full length ABCB4 and ABCB11 sequencing data were already available from the control groups, as well as Carfilzomib from ICPold patients. To allow detection of additional ABCB4 and ABCB11 mutations in the new group, complete sequencing of these two genes was also performed in the 25 newly recruited patients. Genotyping of ABCC2 included all CIC patients, as well as 17 out of 21 patients from the ICPnew group and 16 of 21 patients in the ICPold group, which yielded a total number of 33 patients for ABCC2 genotyping. In nine patients (four ICPnew and five ICPold), no ABCC2 genotyping could be performed for lack of DNA availability.