SLC7A7 and Hyperornithinemia-hyperammonemia-homocitrullinuria: Hyperammonemia is also found in the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome caused by a mutation in the SLC25A15 gene, which encodes the mitochondrial ornithine and citrulline transporter [4], and in lysinuric protein intolerance (LPI) caused by inherited recessive mutations in the SLC7A7 gene, which encodes for the cationic amino-acids transporter subunit y + LAT1 located on the basolateral plasma membrane of epithelial cells and macrophages.