Mutations of the gene coding for the liver paralog AGC2 (SLC25A13) causes neonatal and/or adult-onset type-II citrullinemia (OMIM 603859), an autosomal recessive disease characterized by hyperammonemia and citrullinemia, because of a dysfunctional urea cycle, as well as neuropsychiatric symptoms and fatty liver disease in later life (86, 122). This evidence concerns the gene SLC25A13 and citrullinemia.