Transition of pediatric inborn errors of metabolism with liver manifestations into clinical hepatology-what lies ahead?

Background: Apart from the "classical 4" metabolic liver diseases hemochromatosis, Wilson's disease alpha1-antitrypsin deficiency, and cystic fibrosis (HC, WD, AATD, CF), there are a significant number of infantile and juvenile inborn errors of metabolism with predominant hepatic manifestation. With completion of their 18th year of life, patients should be transferred into adult hepatology. The number of these patients is increasing, because of steadily expanded newborn screening, better biochemical and genetic diagnostics and more refined innovative treatment strategies (e.g. orphan drugs). Objectives: A comprehensive summary of infantile and juvenile inborn errors of metabolism with transition into adult hepatology. Materials and methods: Literature search, presentation of own results and clinical observations and critical reappraisal in view of current and future scientific developments. Results: Transition of patients with inborn errors of metabolism (IEM) into hepatology occurs regularly in five separate clinical categories. These are hepato/splenomegaly, nonalcoholic steatohepatitis (NASH), intrahepatic lesions and hepatocellular carcinoma (HCC) surveillance, status following liver transplantation (post LTX) and "volatile inborn errors of metabolism". Each disease can either lead or contribute to cirrhosis. Conclusion: Apart from the "classical four" (HC, WD, AATD, CF) the clinical care of these young patients with hepatic manifestations of their IEM is both an opportunity and a challenge for hepatologists, both in practice and in the hospital. Apart from specialized university-based outpatient departments there is a need for broader-based structures in clinical hepatology to achieve state-of-the-art diagnostics, monitoring and treatment for the increasing number of patients.