There are two major clinical phenotypes of citrin deficiency, adult-onset type II citrullinemia (CTLN2, OMIM: 603471) and neonatal intrahepatic cholestatic hepatitis (NICCD, OMIM: 605814) [2, 3]. The gene discussed is SLC25A13; the disease is neonatal intrahepatic cholestasis due to citrin deficiency.