In the SLC25A13 gene, 117 different mutations causing AGC2 deficiency have been identified, and the patients, most of them from East and South Asia, are classified into two clinical phenotypes: neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD, also classified as neonatal-onset citrullinemia type II) and adult-onset type II citrullinemia (CTLN2) (Table 1 and Table S1) [103,104]. Here, SLC25A13 is linked to neonatal intrahepatic cholestasis due to citrin deficiency.