As a Clinical Center, UCSF will continue to recruit subjects into the newly prioritized and approved studies, as well as the currently ongoing ChiLDREN studies, and will conduct the procedures for these clinical trials and longitudinal follow-up studies, as described in their respective study protocols, without any deviations. The UCSF Clinical Center will participate in a cooperative and interactive manner with other Clinical Centers, with the Data Coordinating Center, and with the NIDDK in all aspects of the ChiLDREN activities. We plan to continue to carry out the protocols of the ChiLDREN, be open to the concept of a centralized Institutional Review Board at our institution, and agree to be governed by the policies and procedures of the ChiLDREN and its steering committee. We understand that not all Clinical Centers will necessarily participate in all of the approved ChiLDREN protocols. The UCSF Clinical Center is one of the ten original sites in the Biliary Atresia Research Consortium (BARC) which continued, expanded and merged with CLiC to form ChiLDREN. Neonatal hepatitis refers to a heterogeneous group of disorders that result in similar morphologic changes in the livers of infants less than 3 months of age in response to various insults. The term neonatal hepatitis has been used at times to include all causes of cholestasis in infancy in which extra-hepatic biliary obstruction is excluded. Although in many of the cases an etiology cannot be found, specific infectious and metabolic causes have been identified that may present as neonatal hepatitis. Hepatitis in a neonate caused by a known etiologic agent that may be amenable to therapy needs to be differentiated from idiopathic neonatal hepatitis (INH), in which etiologic agents are unknown and probably multiple. At UCSF, we specifically plan to utilize new genetic diagnostic tools and apply them to the rich samples available in the ChiLDREN repository, to elucidate further genetic disorders and factors that contribute to the diagnosis of INH. Application of state- of-the-art genetic technologies and approaches to study of DNA samples from these patients will allow us to explore the genetic etiologies underlying INH and related diagnoses to a much greater breadth and depth than has previously been done, or even been considered possible. Variants that we identify as being associated with INH will also be strong candidates for evaluation in adult liver disorders, such as drug- induced cholestasis. Further, in collaboration with Dr. Ron Sokol at the University of Colorado and Dr. Richard Thompson at King's College Hospital in London, UK we propose to further develop a Progressive Familial Intrahepatic Cholestasis (PFIC) Genotyping Program for diagnostic screening for PFIC and Benign Recurrent Intrahepatic Cholestasis (BRIC) subjects in the ChiLDREN LOGIC study. We propose to shift to more cost-effective and comprehensive experimental approaches making use of current state-of-the art technologies.